TVM Instructions

advanced level

This information is very low-level and could be hard to understand for newcomers.

Introduction

This document provides a list of TVM instructions along with their opcodes and mnemonics.

정보

TVM.pdf document contains a full description of TOS Virtual Machine.

Fift is a stack-based programming language designed to manage TOS smart contracts. The Fift assembler is a Fift library that converts mnemonics of TVM instructions into their binary representation.

A description of Fift, including an introduction to the Fift assembler, can be found here.

This document specifies the corresponding mnemonic for each instruction.

Note the following:

1. Fift is a stack-based language, therefore all the arguments of any instruction are written before it (e.g. 5 PUSHINT, s0 s4 XCHG).
2. Stack registers are denoted by s0, s1, ..., s15. Other stack registers (up to 255) are denoted by i s() (e.g. 100 s()).
3. Control registers are denoted by c0, c1, ..., c15.

Gas prices

The gas price of each instruction is specified in this document. The basic gas price of an instruction is 10 + b, where b is the instruction length in bits. Some operations have additional fees:

1. Parsing cells: Transforming a cell into a slice costs 100 gas units if the cell is loading for the first time and 25 for subsequent loads during the same transaction. For such instructions, two gas prices are specified (e.g. CTOS: 118/43).
2. Cell creation: 500 gas units.
3. Throwing exceptions: 50 gas units. In this document the exception fee is only specified for an instruction if its primary purpose is to throw (e.g. THROWIF, FITS). If the instruction only throws in some cases, two gas prices are specified (e.g. FITS: 26/76).
4. Tuple creation: 1 gas unit for every tuple element.
5. Implicit jumps: 10 gas units for an implicit jump, 5 gas units for an implicit back jump. This fee is not a part of any instruction.
6. Moving stack elements between continuations: 1 gas unit per element, however moving the first 32 elements is free.

Quick search

정보

A full machine-readable list of TVM instructions is available here.

Feel free to use the search field below to find a specific instruction:

Opcode	Fift syntax	Stack	Gas	Description
Please enter a search query

2 Stack manipulation primitives

Here 0 <= i,j,k <= 15 if not stated otherwise.

2.1 Basic stack manipulation primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
00	NOP	-	Does nothing.	18
01	SWAP	x y - y x	Same as s1 XCHG0.	18
0i	s[i] XCHG0		Interchanges s0 with s[i], 1 <= i <= 15.	18
10ij	s[i] s[j] XCHG		Interchanges s[i] with s[j], 1 <= i < j <= 15.	26
11ii	s0 [ii] s() XCHG		Interchanges s0 with s[ii], 0 <= ii <= 255.	26
1i	s1 s[i] XCHG		Interchanges s1 with s[i], 2 <= i <= 15.	18
2i	s[i] PUSH		Pushes a copy of the old s[i] into the stack.	18
20	DUP	x - x x	Same as s0 PUSH.	18
21	OVER	x y - x y x	Same as s1 PUSH.	18
3i	s[i] POP		Pops the old s0 value into the old s[i]. Equivalent to s[i] XCHG0 DROP	18
30	DROP	x -	Same as s0 POP, discards the top-of-stack value.	18
31	NIP	x y - y	Same as s1 POP.	18

2.2 Complex stack manipulation primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
4ijk	s[i] s[j] s[k] XCHG3		Equivalent to s2 s[i] XCHG s1 s[j] XCHG s[k] XCHG0.	26
50ij	s[i] s[j] XCHG2		Equivalent to s1 s[i] XCHG s[j] XCHG0.	26
51ij	s[i] s[j] XCPU		Equivalent to s[i] XCHG0 s[j] PUSH.	26
52ij	s[i] s[j-1] PUXC		Equivalent to s[i] PUSH SWAP s[j] XCHG0.	26
53ij	s[i] s[j] PUSH2		Equivalent to s[i] PUSH s[j+1] PUSH.	26
540ijk	s[i] s[j] s[k] XCHG3_l		Long form of XCHG3.	34
541ijk	s[i] s[j] s[k] XC2PU		Equivalent to s[i] s[j] XCHG2 s[k] PUSH.	34
542ijk	s[i] s[j] s[k-1] XCPUXC		Equivalent to s1 s[i] XCHG s[j] s[k-1] PUXC.	34
543ijk	s[i] s[j] s[k] XCPU2		Equivalent to s[i] XCHG0 s[j] s[k] PUSH2.	34
544ijk	s[i] s[j-1] s[k-1] PUXC2		Equivalent to s[i] PUSH s2 XCHG0 s[j] s[k] XCHG2.	34
545ijk	s[i] s[j-1] s[k-1] PUXCPU		Equivalent to s[i] s[j-1] PUXC s[k] PUSH.	34
546ijk	s[i] s[j-1] s[k-2] PU2XC		Equivalent to s[i] PUSH SWAP s[j] s[k-1] PUXC.	34
547ijk	s[i] s[j] s[k] PUSH3		Equivalent to s[i] PUSH s[j+1] s[k+1] PUSH2.	34
55ij	[i+1] [j+1] BLKSWAP		Permutes two blocks s[j+i+1] … s[j+1] and s[j] … s0. 0 <= i,j <= 15 Equivalent to [i+1] [j+1] REVERSE [j+1] 0 REVERSE [i+j+2] 0 REVERSE.	26
5513	ROT2 2ROT	a b c d e f - c d e f a b	Rotates the three topmost pairs of stack entries.	26
550i	[i+1] ROLL		Rotates the top i+1 stack entries. Equivalent to 1 [i+1] BLKSWAP.	26
55i0	[i+1] -ROLL [i+1] ROLLREV		Rotates the top i+1 stack entries in the other direction. Equivalent to [i+1] 1 BLKSWAP.	26
56ii	[ii] s() PUSH		Pushes a copy of the old s[ii] into the stack. 0 <= ii <= 255	26
57ii	[ii] s() POP		Pops the old s0 value into the old s[ii]. 0 <= ii <= 255	26
58	ROT	a b c - b c a	Equivalent to 1 2 BLKSWAP or to s2 s1 XCHG2.	18
59	ROTREV -ROT	a b c - c a b	Equivalent to 2 1 BLKSWAP or to s2 s2 XCHG2.	18
5A	SWAP2 2SWAP	a b c d - c d a b	Equivalent to 2 2 BLKSWAP or to s3 s2 XCHG2.	18
5B	DROP2 2DROP	a b -	Equivalent to DROP DROP.	18
5C	DUP2 2DUP	a b - a b a b	Equivalent to s1 s0 PUSH2.	18
5D	OVER2 2OVER	a b c d - a b c d a b	Equivalent to s3 s2 PUSH2.	18
5Eij	[i+2] [j] REVERSE		Reverses the order of s[j+i+1] … s[j].	26
5F0i	[i] BLKDROP		Equivalent to DROP performed i times.	26
5Fij	[i] [j] BLKPUSH		Equivalent to PUSH s(j) performed i times. 1 <= i <= 15, 0 <= j <= 15.	26
60	PICK PUSHX		Pops integer i from the stack, then performs s[i] PUSH.	18
61	ROLLX		Pops integer i from the stack, then performs 1 [i] BLKSWAP.	18
62	-ROLLX ROLLREVX		Pops integer i from the stack, then performs [i] 1 BLKSWAP.	18
63	BLKSWX		Pops integers i,j from the stack, then performs [i] [j] BLKSWAP.	18
64	REVX		Pops integers i,j from the stack, then performs [i] [j] REVERSE.	18
65	DROPX		Pops integer i from the stack, then performs [i] BLKDROP.	18
66	TUCK	a b - b a b	Equivalent to SWAP OVER or to s1 s1 XCPU.	18
67	XCHGX		Pops integer i from the stack, then performs s[i] XCHG.	18
68	DEPTH	- depth	Pushes the current depth of the stack.	18
69	CHKDEPTH	i -	Pops integer i from the stack, then checks whether there are at least i elements, generating a stack underflow exception otherwise.	18/58
6A	ONLYTOPX		Pops integer i from the stack, then removes all but the top i elements.	18
6B	ONLYX		Pops integer i from the stack, then leaves only the bottom i elements. Approximately equivalent to DEPTH SWAP SUB DROPX.	18
6Cij	[i] [j] BLKDROP2		Drops i stack elements under the top j elements. 1 <= i <= 15, 0 <= j <= 15 Equivalent to [i+j] 0 REVERSE [i] BLKDROP [j] 0 REVERSE.	26

3 Tuple, List, and Null primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
6D	NULL PUSHNULL	- null	Pushes the only value of type Null.	18
6E	ISNULL	x - ?	Checks whether x is a Null, and returns -1 or 0 accordingly.	18
6F0n	[n] TUPLE	x_1 ... x_n - t	Creates a new Tuple t=(x_1, … ,x_n) containing n values x_1,..., x_n. 0 <= n <= 15	26+n
6F00	NIL	- t	Pushes the only Tuple t=() of length zero.	26
6F01	SINGLE	x - t	Creates a singletos t:=(x), i.e., a Tuple of length one.	27
6F02	PAIR CONS	x y - t	Creates pair t:=(x,y).	28
6F03	TRIPLE	x y z - t	Creates triple t:=(x,y,z).	29
6F1k	[k] INDEX	t - x	Returns the k-th element of a Tuple t. 0 <= k <= 15.	26
6F10	FIRST CAR	t - x	Returns the first element of a Tuple.	26
6F11	SECOND CDR	t - y	Returns the second element of a Tuple.	26
6F12	THIRD	t - z	Returns the third element of a Tuple.	26
6F2n	[n] UNTUPLE	t - x_1 ... x_n	Unpacks a Tuple t=(x_1,...,x_n) of length equal to 0 <= n <= 15. If t is not a Tuple, or if \|t\| != n, a type check exception is thrown.	26+n
6F21	UNSINGLE	t - x	Unpacks a singletos t=(x).	27
6F22	UNPAIR UNCONS	t - x y	Unpacks a pair t=(x,y).	28
6F23	UNTRIPLE	t - x y z	Unpacks a triple t=(x,y,z).	29
6F3k	[k] UNPACKFIRST	t - x_1 ... x_k	Unpacks first 0 <= k <= 15 elements of a Tuple t. If \|t\|<k, throws a type check exception.	26+k
6F30	CHKTUPLE	t -	Checks whether t is a Tuple. If not, throws a type check exception.	26
6F4n	[n] EXPLODE	t - x_1 ... x_m m	Unpacks a Tuple t=(x_1,...,x_m) and returns its length m, but only if m <= n <= 15. Otherwise throws a type check exception.	26+m
6F5k	[k] SETINDEX	t x - t'	Computes Tuple t' that differs from t only at position t'_{k+1}, which is set to x. 0 <= k <= 15 If k >= \|t\|, throws a range check exception.	26+\|t\|
6F50	SETFIRST	t x - t'	Sets the first component of Tuple t to x and returns the resulting Tuple t'.	26+\|t\|
6F51	SETSECOND	t x - t'	Sets the second component of Tuple t to x and returns the resulting Tuple t'.	26+\|t\|
6F52	SETTHIRD	t x - t'	Sets the third component of Tuple t to x and returns the resulting Tuple t'.	26+\|t\|
6F6k	[k] INDEXQ	t - x	Returns the k-th element of a Tuple t, where 0 <= k <= 15. In other words, returns x_{k+1} if t=(x_1,...,x_n). If k>=n, or if t is Null, returns a Null instead of x.	26
6F60	FIRSTQ CARQ	t - x	Returns the first element of a Tuple.	26
6F61	SECONDQ CDRQ	t - y	Returns the second element of a Tuple.	26
6F62	THIRDQ	t - z	Returns the third element of a Tuple.	26
6F7k	[k] SETINDEXQ	t x - t'	Sets the k-th component of Tuple t to x, where 0 <= k < 16, and returns the resulting Tuple t'. If \|t\| <= k, first extends the original Tuple to length n’=k+1 by setting all new components to Null. If the original value of t is Null, treats it as an empty Tuple. If t is not Null or Tuple, throws an exception. If x is Null and either \|t\| <= k or t is Null, then always returns t'=t (and does not consume tuple creation gas).	26+\|t’\|
6F70	SETFIRSTQ	t x - t'	Sets the first component of Tuple t to x and returns the resulting Tuple t'.	26+\|t’\|
6F71	SETSECONDQ	t x - t'	Sets the second component of Tuple t to x and returns the resulting Tuple t'.	26+\|t’\|
6F72	SETTHIRDQ	t x - t'	Sets the third component of Tuple t to x and returns the resulting Tuple t'.	26+\|t’\|
6F80	TUPLEVAR	x_1 ... x_n n - t	Creates a new Tuple t of length n similarly to TUPLE, but with 0 <= n <= 255 taken from the stack.	26+n
6F81	INDEXVAR	t k - x	Similar to k INDEX, but with 0 <= k <= 254 taken from the stack.	26
6F82	UNTUPLEVAR	t n - x_1 ... x_n	Similar to n UNTUPLE, but with 0 <= n <= 255 taken from the stack.	26+n
6F83	UNPACKFIRSTVAR	t n - x_1 ... x_n	Similar to n UNPACKFIRST, but with 0 <= n <= 255 taken from the stack.	26+n
6F84	EXPLODEVAR	t n - x_1 ... x_m m	Similar to n EXPLODE, but with 0 <= n <= 255 taken from the stack.	26+m
6F85	SETINDEXVAR	t x k - t'	Similar to k SETINDEX, but with 0 <= k <= 254 taken from the stack.	26+\|t’\|
6F86	INDEXVARQ	t k - x	Similar to n INDEXQ, but with 0 <= k <= 254 taken from the stack.	26
6F87	SETINDEXVARQ	t x k - t'	Similar to k SETINDEXQ, but with 0 <= k <= 254 taken from the stack.	26+\|t’\|
6F88	TLEN	t - n	Returns the length of a Tuple.	26
6F89	QTLEN	t - n or -1	Similar to TLEN, but returns -1 if t is not a Tuple.	26
6F8A	ISTUPLE	t - ?	Returns -1 or 0 depending on whether t is a Tuple.	26
6F8B	LAST	t - x	Returns the last element of a non-empty Tuple t.	26
6F8C	TPUSH COMMA	t x - t'	Appends a value x to a Tuple t=(x_1,...,x_n), but only if the resulting Tuple t'=(x_1,...,x_n,x) is of length at most 255. Otherwise throws a type check exception.	26+\|t’\|
6F8D	TPOP	t - t' x	Detaches the last element x=x_n from a non-empty Tuple t=(x_1,...,x_n), and returns both the resulting Tuple t'=(x_1,...,x_{n-1}) and the original last element x.	26+\|t’\|
6FA0	NULLSWAPIF	x - x or null x	Pushes a Null under the topmost Integer x, but only if x!=0.	26
6FA1	NULLSWAPIFNOT	x - x or null x	Pushes a Null under the topmost Integer x, but only if x=0. May be used for stack alignment after quiet primitives such as PLDUXQ.	26
6FA2	NULLROTRIF	x y - x y or null x y	Pushes a Null under the second stack entry from the top, but only if the topmost Integer y is non-zero.	26
6FA3	NULLROTRIFNOT	x y - x y or null x y	Pushes a Null under the second stack entry from the top, but only if the topmost Integer y is zero. May be used for stack alignment after quiet primitives such as LDUXQ.	26
6FA4	NULLSWAPIF2	x - x or null null x	Pushes two nulls under the topmost Integer x, but only if x!=0. Equivalent to NULLSWAPIF NULLSWAPIF.	26
6FA5	NULLSWAPIFNOT2	x - x or null null x	Pushes two nulls under the topmost Integer x, but only if x=0. Equivalent to NULLSWAPIFNOT NULLSWAPIFNOT.	26
6FA6	NULLROTRIF2	x y - x y or null null x y	Pushes two nulls under the second stack entry from the top, but only if the topmost Integer y is non-zero. Equivalent to NULLROTRIF NULLROTRIF.	26
6FA7	NULLROTRIFNOT2	x y - x y or null null x y	Pushes two nulls under the second stack entry from the top, but only if the topmost Integer y is zero. Equivalent to NULLROTRIFNOT NULLROTRIFNOT.	26
6FBij	[i] [j] INDEX2	t - x	Recovers x=(t_{i+1})_{j+1} for 0 <= i,j <= 3. Equivalent to [i] INDEX [j] INDEX.	26
6FB4	CADR	t - x	Recovers x=(t_2)_1.	26
6FB5	CDDR	t - x	Recovers x=(t_2)_2.	26
6FE_ijk	[i] [j] [k] INDEX3	t - x	Recovers x=t_{i+1}_{j+1}_{k+1}. 0 <= i,j,k <= 3 Equivalent to [i] [j] INDEX2 [k] INDEX.	26
6FD4	CADDR	t - x	Recovers x=t_2_2_1.	26
6FD5	CDDDR	t - x	Recovers x=t_2_2_2.	26

4 Constant or literal primitives

4.1 Integer and boolean constants

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
7i	[x] PUSHINT [x] INT	- x	Pushes integer x into the stack. -5 <= x <= 10. Here i equals four lower-order bits of x (i=x mod 16).	18
70	ZERO FALSE	- 0		18
71	ONE	- 1		18
72	TWO	- 2		18
7A	TEN	- 10		18
7F	TRUE	- -1		18
80xx	[xx] PUSHINT [xx] INT	- xx	Pushes integer xx. -128 <= xx <= 127.	26
81xxxx	[xxxx] PUSHINT [xxxx] INT	- xxxx	Pushes integer xxxx. -2^15 <= xx < 2^15.	34
82lxxx	[xxx] PUSHINT [xxx] INT	- xxx	Pushes integer xxx. Details: 5-bit 0 <= l <= 30 determines the length n=8l+19 of signed big-endian integer xxx. The total length of this instruction is l+4 bytes or n+13=8l+32 bits.	23
83xx	[xx+1] PUSHPOW2	- 2^(xx+1)	(Quietly) pushes 2^(xx+1) for 0 <= xx <= 255. 2^256 is a NaN.	26
83FF	PUSHNAN	- NaN	Pushes a NaN.	26
84xx	[xx+1] PUSHPOW2DEC	- 2^(xx+1)-1	Pushes 2^(xx+1)-1 for 0 <= xx <= 255.	26
85xx	[xx+1] PUSHNEGPOW2	- -2^(xx+1)	Pushes -2^(xx+1) for 0 <= xx <= 255.	26

4.2 Constant slices, continuations, cells, and references

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
88	[ref] PUSHREF	- c	Pushes the reference ref into the stack. Details: Pushes the first reference of cc.code into the stack as a Cell (and removes this reference from the current continuation).	18
89	[ref] PUSHREFSLICE	- s	Similar to PUSHREF, but converts the cell into a Slice.	118/43
8A	[ref] PUSHREFCONT	- cont	Similar to PUSHREFSLICE, but makes a simple ordinary Continuation out of the cell.	118/43
8Bxsss	[slice] PUSHSLICE [slice] SLICE	- s	Pushes the slice slice into the stack. Details: Pushes the (prefix) subslice of cc.code consisting of its first 8x+4 bits and no references (i.e., essentially a bitstring), where 0 <= x <= 15. A completion tag is assumed, meaning that all trailing zeroes and the last binary one (if present) are removed from this bitstring. If the original bitstring consists only of zeroes, an empty slice will be pushed.	22
8Crxxssss	[slice] PUSHSLICE [slice] SLICE	- s	Pushes the slice slice into the stack. Details: Pushes the (prefix) subslice of cc.code consisting of its first 1 <= r+1 <= 4 references and up to first 8xx+1 bits of data, with 0 <= xx <= 31. A completion tag is also assumed.	25
8Drxxsssss	[slice] PUSHSLICE [slice] SLICE	- s	Pushes the slice slice into the stack. Details: Pushes the subslice of cc.code consisting of 0 <= r <= 4 references and up to 8xx+6 bits of data, with 0 <= xx <= 127. A completion tag is assumed.	28
	x{} PUSHSLICE x{ABCD1234} PUSHSLICE b{01101} PUSHSLICE	- s	Examples of PUSHSLICE. x{} is an empty slice. x{...} is a hexadecimal literal. b{...} is a binary literal. More on slice literals here. Note that the assembler can replace PUSHSLICE with PUSHREFSLICE in certain situations (e.g. if there’s not enough space in the current continuation).
	<b x{AB12} s, b> PUSHREF <b x{AB12} s, b> PUSHREFSLICE	- c/s	Examples of PUSHREF and PUSHREFSLICE. More on building cells in fift here.
8F_rxxcccc	[builder] PUSHCONT [builder] CONT	- c	Pushes a continuation made from builder. Details: Pushes the simple ordinary continuation cccc made from the first 0 <= r <= 3 references and the first 0 <= xx <= 127 bytes of cc.code.	26
9xccc	[builder] PUSHCONT [builder] CONT	- c	Pushes a continuation made from builder. Details: Pushes an x-byte continuation for 0 <= x <= 15.	18
	<{ code }> PUSHCONT <{ code }> CONT CONT:<{ code }>	- c	Pushes a continuation with code code. Note that the assembler can replace PUSHCONT with PUSHREFCONT in certain situations (e.g. if there’s not enough space in the current continuation).

5 Arithmetic primitives

5.1 Addition, subtraction, multiplication

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
A0	ADD	x y - x+y		18
A1	SUB	x y - x-y		18
A2	SUBR	x y - y-x	Equivalent to SWAP SUB.	18
A3	NEGATE	x - -x	Equivalent to -1 MULCONST or to ZERO SUBR. Notice that it triggers an integer overflow exception if x=-2^256.	18
A4	INC	x - x+1	Equivalent to 1 ADDCONST.	18
A5	DEC	x - x-1	Equivalent to -1 ADDCONST.	18
A6cc	[cc] ADDCONST [cc] ADDINT [-cc] SUBCONST [-cc] SUBINT	x - x+cc	-128 <= cc <= 127.	26
A7cc	[cc] MULCONST [cc] MULINT	x - x*cc	-128 <= cc <= 127.	26
A8	MUL	x y - x*y		18

5.2 Division

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
A9mscdf			This is the general encoding of division, with an optional pre-multiplication and an optional replacement of the division or multiplication by a shift. Variable fields are as follows: 0 <= m <= 1 - Indicates whether there is pre-multiplication (MULDIV and its variants), possibly replaced by a left shift. 0 <= s <= 2 - Indicates whether either the multiplication or the division have been replaced by shifts: s=0 - no replacement, s=1 - division replaced by a right shift, s=2 - multiplication replaced by a left shift (possible only for m=1). 0 <= c <= 1 - Indicates whether there is a constant one-byte argument tt for the shift operator (if s!=0). For s=0, c=0. If c=1, then 0 <= tt <= 255, and the shift is performed by tt+1 bits. If s!=0 and c=0, then the shift amount is provided to the instruction as a top-of-stack Integer in range 0...256. 1 <= d <= 3 - Indicates which results of division are required: 1 - only the quotient, 2 - only the remainder, 3 - both. 0 <= f <= 2 - Rounding mode: 0 - floor, 1 - nearest integer, 2 - ceiling. All instructions below are variants of this.	26
A904	DIV	x y - q	q=floor(x/y), r=x-y*q	26
A905	DIVR	x y - q’	q’=round(x/y), r’=x-y*q’	26
A906	DIVC	x y - q''	q’’=ceil(x/y), r’’=x-y*q’’	26
A908	MOD	x y - r		26
A90C	DIVMOD	x y - q r		26
A90D	DIVMODR	x y - q' r'		26
A90E	DIVMODC	x y - q'' r''		26
A925	RSHIFTR	x y - round(x/2^y)		26
A926	RSHIFTC	x y - ceil(x/2^y)		34
A935tt	[tt+1] RSHIFTR#	x y - round(x/2^(tt+1))		34
A936tt	[tt+1] RSHIFTC#	x y - ceil(x/2^(tt+1))		34
A938tt	[tt+1] MODPOW2#	x - x mod 2^(tt+1)		26
A98	MULDIV	x y z - q	q=floor(x*y/z)	26
A985	MULDIVR	x y z - q'	q'=round(x*y/z)	26
A98C	MULDIVMOD	x y z - q r	q=floor(x*y/z), r=x*y-z*q	26
A9A4	MULRSHIFT	x y z - floor(x*y/2^z)	0 <= z <= 256	26
A9A5	MULRSHIFTR	x y z - round(x*y/2^z)	0 <= z <= 256	26
A9A6	MULRSHIFTC	x y z - ceil(x*y/2^z)	0 <= z <= 256	34
A9B4tt	[tt+1] MULRSHIFT#	x y - floor(x*y/2^(tt+1))		34
A9B5tt	[tt+1] MULRSHIFTR#	x y - round(x*y/2^(tt+1))		34
A9B6tt	[tt+1] MULRSHIFTC#	x y - ceil(x*y/2^(tt+1))		26
A9C4	LSHIFTDIV	x y z - floor(2^z*x/y)	0 <= z <= 256	26
A9C5	LSHIFTDIVR	x y z - round(2^z*x/y)	0 <= z <= 256	26
A9C6	LSHIFTDIVC	x y z - ceil(2^z*x/y)	0 <= z <= 256	34
A9D4tt	[tt+1] LSHIFT#DIV	x y - floor(2^(tt+1)*x/y)		34
A9D5tt	[tt+1] LSHIFT#DIVR	x y - round(2^(tt+1)*x/y)		34
A9D6tt	[tt+1] LSHIFT#DIVC	x y - ceil(2^(tt+1)*x/y)		26

5.3 Shifts, logical operations

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
AAcc	[cc+1] LSHIFT#	x - x*2^(cc+1)	0 <= cc <= 255	26
ABcc	[cc+1] RSHIFT#	x - floor(x/2^(cc+1))	0 <= cc <= 255	18
AC	LSHIFT	x y - x*2^y	0 <= y <= 1023	18
AD	RSHIFT	x y - floor(x/2^y)	0 <= y <= 1023	18
AE	POW2	y - 2^y	0 <= y <= 1023 Equivalent to ONE SWAP LSHIFT.	18
B0	AND	x y - x&y	Bitwise and of two signed integers x and y, sign-extended to infinity.	18
B1	OR	x y - x\|y	Bitwise or of two integers.	18
B2	XOR	x y - x xor y	Bitwise xor of two integers.	18
B3	NOT	x - ~x	Bitwise not of an integer.	26
B4cc	[cc+1] FITS	x - x	Checks whether x is a cc+1-bit signed integer for 0 <= cc <= 255 (i.e., whether -2^cc <= x < 2^cc). If not, either triggers an integer overflow exception, or replaces x with a NaN (quiet version).	26/76
B400	CHKBOOL	x - x	Checks whether x is a “boolean value'' (i.e., either 0 or -1).	26/76
B5cc	[cc+1] UFITS	x - x	Checks whether x is a cc+1-bit unsigned integer for 0 <= cc <= 255 (i.e., whether 0 <= x < 2^(cc+1)).	26/76
B500	CHKBIT	x - x	Checks whether x is a binary digit (i.e., zero or one).	26/76
B600	FITSX	x c - x	Checks whether x is a c-bit signed integer for 0 <= c <= 1023.	26/76
B601	UFITSX	x c - x	Checks whether x is a c-bit unsigned integer for 0 <= c <= 1023.	26/76
B602	BITSIZE	x - c	Computes smallest c >= 0 such that x fits into a c-bit signed integer (-2^(c-1) <= c < 2^(c-1)).	26
B603	UBITSIZE	x - c	Computes smallest c >= 0 such that x fits into a c-bit unsigned integer (0 <= x < 2^c), or throws a range check exception.	26
B608	MIN	x y - x or y	Computes the minimum of two integers x and y.	26
B609	MAX	x y - x or y	Computes the maximum of two integers x and y.	26
B60A	MINMAX INTSORT2	x y - x y or y x	Sorts two integers. Quiet version of this operation returns two NaNs if any of the arguments are NaNs.	26
B60B	ABS	x - \|x\|	Computes the absolute value of an integer x.	26

5.4 Quiet arithmetic primitives

Quiet operations return NaN instead of throwing exceptions if one of their arguments is a NaN or in the case of an integer overflow. Quiet operations have a prefix Q as shown below. Another way to make an operation quiet is to add QUIET before it (i.e. one can write QUIET ADD instead of QADD). Quiet versions of integer comparison primitives are also available (QUIET SGN, QUIET LESS etc).

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
B7A0	QADD	x y - x+y		26
B7A1	QSUB	x y - x-y		26
B7A2	QSUBR	x y - y-x		26
B7A3	QNEGATE	x - -x		26
B7A4	QINC	x - x+1		26
B7A5	QDEC	x - x-1		26
B7A8	QMUL	x y - x*y		26
B7A904	QDIV	x y - q	Division returns NaN if y=0.	34
B7A905	QDIVR	x y - q’		34
B7A906	QDIVC	x y - q''		34
B7A908	QMOD	x y - r		34
B7A90C	QDIVMOD	x y - q r		34
B7A90D	QDIVMODR	x y - q' r'		34
B7A90E	QDIVMODC	x y - q'' r''		34
B7A985	QMULDIVR	x y z - q'		34
B7A98C	QMULDIVMOD	x y z - q r		34
B7AC	QLSHIFT	x y - x*2^y		26
B7AD	QRSHIFT	x y - floor(x/2^y)		26
B7AE	QPOW2	y - 2^y		26
B7B0	QAND	x y - x&y		26
B7B1	QOR	x y - x\|y		26
B7B2	QXOR	x y - x xor y		26
B7B3	QNOT	x - ~x		26
B7B4cc	[cc+1] QFITS	x - x	Replaces x with a NaN if x is not a cc+1-bit signed integer, leaves it intact otherwise.	34
B7B5cc	[cc+1] QUFITS	x - x	Replaces x with a NaN if x is not a cc+1-bit unsigned integer, leaves it intact otherwise.	34
B7B600	QFITSX	x c - x	Replaces x with a NaN if x is not a c-bit signed integer, leaves it intact otherwise.	34
B7B601	QUFITSX	x c - x	Replaces x with a NaN if x is not a c-bit unsigned integer, leaves it intact otherwise.	34

6 Comparison primitives

6.1 Integer comparison

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
B8	SGN	x - sgn(x)	Computes the sign of an integer x: -1 if x<0, 0 if x=0, 1 if x>0.	18
B9	LESS	x y - x<y	Returns -1 if x<y, 0 otherwise.	18
BA	EQUAL	x y - x=y	Returns -1 if x=y, 0 otherwise.	18
BB	LEQ	x y - x<=y		18
BC	GREATER	x y - x>y		18
BD	NEQ	x y - x!=y	Equivalent to EQUAL NOT.	18
BE	GEQ	x y - x>=y	Equivalent to LESS NOT.	18
BF	CMP	x y - sgn(x-y)	Computes the sign of x-y: -1 if x<y, 0 if x=y, 1 if x>y. No integer overflow can occur here unless x or y is a NaN.	18
C0yy	[yy] EQINT	x - x=yy	Returns -1 if x=yy, 0 otherwise. -2^7 <= yy < 2^7.	26
C000	ISZERO	x - x=0	Checks whether an integer is zero. Corresponds to Forth's 0=.	26
C1yy	[yy] LESSINT [yy-1] LEQINT	x - x<yy	Returns -1 if x<yy, 0 otherwise. -2^7 <= yy < 2^7.	26
C100	ISNEG	x - x<0	Checks whether an integer is negative. Corresponds to Forth's 0<.	26
C101	ISNPOS	x - x<=0	Checks whether an integer is non-positive.	26
C2yy	[yy] GTINT [yy+1] GEQINT	x - x>yy	Returns -1 if x>yy, 0 otherwise. -2^7 <= yy < 2^7.	26
C200	ISPOS	x - x>0	Checks whether an integer is positive. Corresponds to Forth's 0>.	26
C2FF	ISNNEG	x - x >=0	Checks whether an integer is non-negative.	26
C3yy	[yy] NEQINT	x - x!=yy	Returns -1 if x!=yy, 0 otherwise. -2^7 <= yy < 2^7.	26
C4	ISNAN	x - x=NaN	Checks whether x is a NaN.	18
C5	CHKNAN	x - x	Throws an arithmetic overflow exception if x is a NaN.	18/68

6.2 Other comparison

Most of these "other comparison" primitives actually compare the data portions of Slices as bitstrings (ignoring references if not stated otherwise).

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
C700	SEMPTY	s - ?	Checks whether a Slice s is empty (i.e., contains no bits of data and no cell references).	26
C701	SDEMPTY	s - ?	Checks whether Slice s has no bits of data.	26
C702	SREMPTY	s - ?	Checks whether Slice s has no references.	26
C703	SDFIRST	s - ?	Checks whether the first bit of Slice s is a one.	26
C704	SDLEXCMP	s s' - x	Compares the data of s lexicographically with the data of s', returning -1, 0, or 1 depending on the result.	26
C705	SDEQ	s s' - ?	Checks whether the data parts of s and s' coincide, equivalent to SDLEXCMP ISZERO.	26
C708	SDPFX	s s' - ?	Checks whether s is a prefix of s'.	26
C709	SDPFXREV	s s' - ?	Checks whether s' is a prefix of s, equivalent to SWAP SDPFX.	26
C70A	SDPPFX	s s' - ?	Checks whether s is a proper prefix of s' (i.e., a prefix distinct from s').	26
C70B	SDPPFXREV	s s' - ?	Checks whether s' is a proper prefix of s.	26
C70C	SDSFX	s s' - ?	Checks whether s is a suffix of s'.	26
C70D	SDSFXREV	s s' - ?	Checks whether s' is a suffix of s.	26
C70E	SDPSFX	s s' - ?	Checks whether s is a proper suffix of s'.	26
C70F	SDPSFXREV	s s' - ?	Checks whether s' is a proper suffix of s.	26
C710	SDCNTLEAD0	s - n	Returns the number of leading zeroes in s.	26
C711	SDCNTLEAD1	s - n	Returns the number of leading ones in s.	26
C712	SDCNTTRAIL0	s - n	Returns the number of trailing zeroes in s.	26
C713	SDCNTTRAIL1	s - n	Returns the number of trailing ones in s.	26

7 Cell primitives

7.1 Cell serialization primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
C8	NEWC	- b	Creates a new empty Builder.	18
C9	ENDC	b - c	Converts a Builder into an ordinary Cell.	518
CAcc	[cc+1] STI	x b - b'	Stores a signed cc+1-bit integer x into Builder b for 0 <= cc <= 255, throws a range check exception if x does not fit into cc+1 bits.	26
CBcc	[cc+1] STU	x b - b'	Stores an unsigned cc+1-bit integer x into Builder b. In all other respects it is similar to STI.	26
CC	STREF	c b - b'	Stores a reference to Cell c into Builder b.	18
CD	STBREFR ENDCST	b b'' - b	Equivalent to ENDC SWAP STREF.	518
CE	STSLICE	s b - b'	Stores Slice s into Builder b.	18
CF00	STIX	x b l - b'	Stores a signed l-bit integer x into b for 0 <= l <= 257.	26
CF01	STUX	x b l - b'	Stores an unsigned l-bit integer x into b for 0 <= l <= 256.	26
CF02	STIXR	b x l - b'	Similar to STIX, but with arguments in a different order.	26
CF03	STUXR	b x l - b'	Similar to STUX, but with arguments in a different order.	26
CF04	STIXQ	x b l - x b f or b' 0	A quiet version of STIX. If there is no space in b, sets b'=b and f=-1. If x does not fit into l bits, sets b'=b and f=1. If the operation succeeds, b' is the new Builder and f=0. However, 0 <= l <= 257, with a range check exception if this is not so.	26
CF05	STUXQ	x b l - x b f or b' 0	A quiet version of STUX.	26
CF06	STIXRQ	b x l - b x f or b' 0	A quiet version of STIXR.	26
CF07	STUXRQ	b x l - b x f or b' 0	A quiet version of STUXR.	26
CF08cc	[cc+1] STI_l	x b - b'	A longer version of [cc+1] STI.	34
CF09cc	[cc+1] STU_l	x b - b'	A longer version of [cc+1] STU.	34
CF0Acc	[cc+1] STIR	b x - b'	Equivalent to SWAP [cc+1] STI.	34
CF0Bcc	[cc+1] STUR	b x - b'	Equivalent to SWAP [cc+1] STU.	34
CF0Ccc	[cc+1] STIQ	x b - x b f or b' 0	A quiet version of STI.	34
CF0Dcc	[cc+1] STUQ	x b - x b f or b' 0	A quiet version of STU.	34
CF0Ecc	[cc+1] STIRQ	b x - b x f or b' 0	A quiet version of STIR.	34
CF0Fcc	[cc+1] STURQ	b x - b x f or b' 0	A quiet version of STUR.	34
CF10	STREF_l	c b - b'	A longer version of STREF.	26
CF11	STBREF	b' b - b''	Equivalent to SWAP STBREFR.	526
CF12	STSLICE_l	s b - b'	A longer version of STSLICE.	26
CF13	STB	b' b - b''	Appends all data from Builder b' to Builder b.	26
CF14	STREFR	b c - b'	Equivalent to SWAP STREF.	26
CF15	STBREFR_l	b b' - b''	A longer encoding of STBREFR.	526
CF16	STSLICER	b s - b'	Equivalent to SWAP STSLICE.	26
CF17	STBR BCONCAT	b b' - b''	Concatenates two builders. Equivalent to SWAP STB.	26
CF18	STREFQ	c b - c b -1 or b' 0	Quiet version of STREF.	26
CF19	STBREFQ	b' b - b' b -1 or b'' 0	Quiet version of STBREF.	526
CF1A	STSLICEQ	s b - s b -1 or b' 0	Quiet version of STSLICE.	26
CF1B	STBQ	b' b - b' b -1 or b'' 0	Quiet version of STB.	26
CF1C	STREFRQ	b c - b c -1 or b' 0	Quiet version of STREFR.	26
CF1D	STBREFRQ	b b' - b b' -1 or b'' 0	Quiet version of STBREFR.	526
CF1E	STSLICERQ	b s - b s -1 or b'' 0	Quiet version of STSLICER.	26
CF1F	STBRQ BCONCATQ	b b' - b b' -1 or b'' 0	Quiet version of STBR.	26
CF20	[ref] STREFCONST	b - b’	Equivalent to PUSHREF STREFR.	26
CF21	[ref] [ref] STREF2CONST	b - b’	Equivalent to STREFCONST STREFCONST.	26
CF23		b x - c	If x!=0, creates a special or exotic cell from Builder b. The type of the exotic cell must be stored in the first 8 bits of b. If x=0, it is equivalent to ENDC. Otherwise some validity checks on the data and references of b are performed before creating the exotic cell.	526
CF28	STILE4	x b - b'	Stores a little-endian signed 32-bit integer.	26
CF29	STULE4	x b - b'	Stores a little-endian unsigned 32-bit integer.	26
CF2A	STILE8	x b - b'	Stores a little-endian signed 64-bit integer.	26
CF2B	STULE8	x b - b'	Stores a little-endian unsigned 64-bit integer.	26
CF30	BDEPTH	b - x	Returns the depth of Builder b. If no cell references are stored in b, then x=0; otherwise x is one plus the maximum of depths of cells referred to from b.	26
CF31	BBITS	b - x	Returns the number of data bits already stored in Builder b.	26
CF32	BREFS	b - y	Returns the number of cell references already stored in b.	26
CF33	BBITREFS	b - x y	Returns the numbers of both data bits and cell references in b.	26
CF35	BREMBITS	b - x'	Returns the number of data bits that can still be stored in b.	26
CF36	BREMREFS	b - y'	Returns the number of references that can still be stored in b.	26
CF37	BREMBITREFS	b - x' y'	Returns the numbers of both data bits and references that can still be stored in b.	26
CF38cc	[cc+1] BCHKBITS#	b -	Checks whether cc+1 bits can be stored into b, where 0 <= cc <= 255.	34/84
CF39	BCHKBITS	b x -	Checks whether x bits can be stored into b, 0 <= x <= 1023. If there is no space for x more bits in b, or if x is not within the range 0...1023, throws an exception.	26/76
CF3A	BCHKREFS	b y -	Checks whether y references can be stored into b, 0 <= y <= 7.	26/76
CF3B	BCHKBITREFS	b x y -	Checks whether x bits and y references can be stored into b, 0 <= x <= 1023, 0 <= y <= 7.	26/76
CF3Ccc	[cc+1] BCHKBITSQ#	b - ?	Checks whether cc+1 bits can be stored into b, where 0 <= cc <= 255.	34
CF3D	BCHKBITSQ	b x - ?	Checks whether x bits can be stored into b, 0 <= x <= 1023.	26
CF3E	BCHKREFSQ	b y - ?	Checks whether y references can be stored into b, 0 <= y <= 7.	26
CF3F	BCHKBITREFSQ	b x y - ?	Checks whether x bits and y references can be stored into b, 0 <= x <= 1023, 0 <= y <= 7.	26
CF40	STZEROES	b n - b'	Stores n binary zeroes into Builder b.	26
CF41	STOSES	b n - b'	Stores n binary ones into Builder b.	26
CF42	STSAME	b n x - b'	Stores n binary xes (0 <= x <= 1) into Builder b.	26
CFC0_xysss	[slice] STSLICECONST	b - b'	Stores a constant subslice sss. Details: sss consists of 0 <= x <= 3 references and up to 8y+2 data bits, with 0 <= y <= 7. Completion bit is assumed. Note that the assembler can replace STSLICECONST with PUSHSLICE STSLICER if the slice is too big.	24
CF81	STZERO	b - b'	Stores one binary zero.	24
CF83	STOSE	b - b'	Stores one binary one.	24

7.2 Cell deserialization primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
D0	CTOS	c - s	Converts a Cell into a Slice. Notice that c must be either an ordinary cell, or an exotic cell which is automatically loaded to yield an ordinary cell c', converted into a Slice afterwards.	118/43
D1	ENDS	s -	Removes a Slice s from the stack, and throws an exception if it is not empty.	18/68
D2cc	[cc+1] LDI	s - x s'	Loads (i.e., parses) a signed cc+1-bit integer x from Slice s, and returns the remainder of s as s'.	26
D3cc	[cc+1] LDU	s - x s'	Loads an unsigned cc+1-bit integer x from Slice s.	26
D4	LDREF	s - c s'	Loads a cell reference c from s.	18
D5	LDREFRTOS	s - s' s''	Equivalent to LDREF SWAP CTOS.	118/43
D6cc	[cc+1] LDSLICE	s - s'' s'	Cuts the next cc+1 bits of s into a separate Slice s''.	26
D700	LDIX	s l - x s'	Loads a signed l-bit (0 <= l <= 257) integer x from Slice s, and returns the remainder of s as s'.	26
D701	LDUX	s l - x s'	Loads an unsigned l-bit integer x from (the first l bits of) s, with 0 <= l <= 256.	26
D702	PLDIX	s l - x	Preloads a signed l-bit integer from Slice s, for 0 <= l <= 257.	26
D703	PLDUX	s l - x	Preloads an unsigned l-bit integer from s, for 0 <= l <= 256.	26
D704	LDIXQ	s l - x s' -1 or s 0	Quiet version of LDIX: loads a signed l-bit integer from s similarly to LDIX, but returns a success flag, equal to -1 on success or to 0 on failure (if s does not have l bits), instead of throwing a cell underflow exception.	26
D705	LDUXQ	s l - x s' -1 or s 0	Quiet version of LDUX.	26
D706	PLDIXQ	s l - x -1 or 0	Quiet version of PLDIX.	26
D707	PLDUXQ	s l - x -1 or 0	Quiet version of PLDUX.	26
D708cc	[cc+1] LDI_l	s - x s'	A longer encoding for LDI.	34
D709cc	[cc+1] LDU_l	s - x s'	A longer encoding for LDU.	34
D70Acc	[cc+1] PLDI	s - x	Preloads a signed cc+1-bit integer from Slice s.	34
D70Bcc	[cc+1] PLDU	s - x	Preloads an unsigned cc+1-bit integer from s.	34
D70Ccc	[cc+1] LDIQ	s - x s' -1 or s 0	A quiet version of LDI.	34
D70Dcc	[cc+1] LDUQ	s - x s' -1 or s 0	A quiet version of LDU.	34
D70Ecc	[cc+1] PLDIQ	s - x -1 or 0	A quiet version of PLDI.	34
D70Fcc	[cc+1] PLDUQ	s - x -1 or 0	A quiet version of PLDU.	34
D714_c	[32(c+1)] PLDUZ	s - s x	Preloads the first 32(c+1) bits of Slice s into an unsigned integer x, for 0 <= c <= 7. If s is shorter than necessary, missing bits are assumed to be zero. This operation is intended to be used along with IFBITJMP and similar instructions.	26
D718	LDSLICEX	s l - s'' s'	Loads the first 0 <= l <= 1023 bits from Slice s into a separate Slice s'', returning the remainder of s as s'.	26
D719	PLDSLICEX	s l - s''	Returns the first 0 <= l <= 1023 bits of s as s''.	26
D71A	LDSLICEXQ	s l - s'' s' -1 or s 0	A quiet version of LDSLICEX.	26
D71B	PLDSLICEXQ	s l - s' -1 or 0	A quiet version of LDSLICEXQ.	26
D71Ccc	[cc+1] LDSLICE_l	s - s'' s'	A longer encoding for LDSLICE.	34
D71Dcc	[cc+1] PLDSLICE	s - s''	Returns the first 0 < cc+1 <= 256 bits of s as s''.	34
D71Ecc	[cc+1] LDSLICEQ	s - s'' s' -1 or s 0	A quiet version of LDSLICE.	34
D71Fcc	[cc+1] PLDSLICEQ	s - s'' -1 or 0	A quiet version of PLDSLICE.	34
D720	SDCUTFIRST	s l - s'	Returns the first 0 <= l <= 1023 bits of s. It is equivalent to PLDSLICEX.	26
D721	SDSKIPFIRST	s l - s'	Returns all but the first 0 <= l <= 1023 bits of s. It is equivalent to LDSLICEX NIP.	26
D722	SDCUTLAST	s l - s'	Returns the last 0 <= l <= 1023 bits of s.	26
D723	SDSKIPLAST	s l - s'	Returns all but the last 0 <= l <= 1023 bits of s.	26
D724	SDSUBSTR	s l l' - s'	Returns 0 <= l' <= 1023 bits of s starting from offset 0 <= l <= 1023, thus extracting a bit substring out of the data of s.	26
D726	SDBEGINSX	s s' - s''	Checks whether s begins with (the data bits of) s', and removes s' from s on success. On failure throws a cell deserialization exception. Primitive SDPFXREV can be considered a quiet version of SDBEGINSX.	26
D727	SDBEGINSXQ	s s' - s'' -1 or s 0	A quiet version of SDBEGINSX.	26
D72A_xsss	[slice] SDBEGINS	s - s''	Checks whether s begins with constant bitstring sss of length 8x+3 (with continuation bit assumed), where 0 <= x <= 127, and removes sss from s on success.	31
D72E_xsss	[slice] SDBEGINSQ	s - s'' -1 or s 0	A quiet version of SDBEGINS.	31
D730	SCUTFIRST	s l r - s'	Returns the first 0 <= l <= 1023 bits and first 0 <= r <= 4 references of s.	26
D731	SSKIPFIRST	s l r - s'	Returns all but the first l bits of s and r references of s.	26
D732	SCUTLAST	s l r - s'	Returns the last 0 <= l <= 1023 data bits and last 0 <= r <= 4 references of s.	26
D733	SSKIPLAST	s l r - s'	Returns all but the last l bits of s and r references of s.	26
D734	SUBSLICE	s l r l' r' - s'	Returns 0 <= l' <= 1023 bits and 0 <= r' <= 4 references from Slice s, after skipping the first 0 <= l <= 1023 bits and first 0 <= r <= 4 references.	26
D736	SPLIT	s l r - s' s''	Splits the first 0 <= l <= 1023 data bits and first 0 <= r <= 4 references from s into s', returning the remainder of s as s''.	26
D737	SPLITQ	s l r - s' s'' -1 or s 0	A quiet version of SPLIT.	26
D739		c - s ?	Transforms an ordinary or exotic cell into a Slice, as if it were an ordinary cell. A flag is returned indicating whether c is exotic. If that be the case, its type can later be deserialized from the first eight bits of s.
D73A		c - c'	Loads an exotic cell c and returns an ordinary cell c'. If c is already ordinary, does nothing. If c cannot be loaded, throws an exception.
D73B		c - c' -1 or c 0	Loads an exotic cell c and returns an ordinary cell c'. If c is already ordinary, does nothing. If c cannot be loaded, returns 0.
D741	SCHKBITS	s l -	Checks whether there are at least l data bits in Slice s. If this is not the case, throws a cell deserialisation (i.e., cell underflow) exception.	26/76
D742	SCHKREFS	s r -	Checks whether there are at least r references in Slice s.	26/76
D743	SCHKBITREFS	s l r -	Checks whether there are at least l data bits and r references in Slice s.	26/76
D745	SCHKBITSQ	s l - ?	Checks whether there are at least l data bits in Slice s.	26
D746	SCHKREFSQ	s r - ?	Checks whether there are at least r references in Slice s.	26
D747	SCHKBITREFSQ	s l r - ?	Checks whether there are at least l data bits and r references in Slice s.	26
D748	PLDREFVAR	s n - c	Returns the n-th cell reference of Slice s for 0 <= n <= 3.	26
D749	SBITS	s - l	Returns the number of data bits in Slice s.	26
D74A	SREFS	s - r	Returns the number of references in Slice s.	26
D74B	SBITREFS	s - l r	Returns both the number of data bits and the number of references in s.	26
D74E_n	[n] PLDREFIDX	s - c	Returns the n-th cell reference of Slice s, where 0 <= n <= 3.	26
D74C	PLDREF	s - c	Preloads the first cell reference of a Slice.	26
D750	LDILE4	s - x s'	Loads a little-endian signed 32-bit integer.	26
D751	LDULE4	s - x s'	Loads a little-endian unsigned 32-bit integer.	26
D752	LDILE8	s - x s'	Loads a little-endian signed 64-bit integer.	26
D753	LDULE8	s - x s'	Loads a little-endian unsigned 64-bit integer.	26
D754	PLDILE4	s - x	Preloads a little-endian signed 32-bit integer.	26
D755	PLDULE4	s - x	Preloads a little-endian unsigned 32-bit integer.	26
D756	PLDILE8	s - x	Preloads a little-endian signed 64-bit integer.	26
D757	PLDULE8	s - x	Preloads a little-endian unsigned 64-bit integer.	26
D758	LDILE4Q	s - x s' -1 or s 0	Quietly loads a little-endian signed 32-bit integer.	26
D759	LDULE4Q	s - x s' -1 or s 0	Quietly loads a little-endian unsigned 32-bit integer.	26
D75A	LDILE8Q	s - x s' -1 or s 0	Quietly loads a little-endian signed 64-bit integer.	26
D75B	LDULE8Q	s - x s' -1 or s 0	Quietly loads a little-endian unsigned 64-bit integer.	26
D75C	PLDILE4Q	s - x -1 or 0	Quietly preloads a little-endian signed 32-bit integer.	26
D75D	PLDULE4Q	s - x -1 or 0	Quietly preloads a little-endian unsigned 32-bit integer.	26
D75E	PLDILE8Q	s - x -1 or 0	Quietly preloads a little-endian signed 64-bit integer.	26
D75F	PLDULE8Q	s - x -1 or 0	Quietly preloads a little-endian unsigned 64-bit integer.	26
D760	LDZEROES	s - n s'	Returns the count n of leading zero bits in s, and removes these bits from s.	26
D761	LDONES	s - n s'	Returns the count n of leading one bits in s, and removes these bits from s.	26
D762	LDSAME	s x - n s'	Returns the count n of leading bits equal to 0 <= x <= 1 in s, and removes these bits from s.	26
D764	SDEPTH	s - x	Returns the depth of Slice s. If s has no references, then x=0; otherwise x is one plus the maximum of depths of cells referred to from s.	26
D765	CDEPTH	c - x	Returns the depth of Cell c. If c has no references, then x=0; otherwise x is one plus the maximum of depths of cells referred to from c. If c is a Null instead of a Cell, returns zero.	26

8 Continuation and control flow primitives

8.1 Unconditional control flow primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
D8	EXECUTE CALLX	c -	Calls, or executes, continuation c.	18
D9	JMPX	c -	Jumps, or transfers control, to continuation c. The remainder of the previous current continuation cc is discarded.	18
DApr	[p] [r] CALLXARGS	c -	Calls continuation c with p parameters and expecting r return values 0 <= p <= 15, 0 <= r <= 15	26
DB0p	[p] -1 CALLXARGS	c -	Calls continuation c with 0 <= p <= 15 parameters, expecting an arbitrary number of return values.	26
DB1p	[p] JMPXARGS	c -	Jumps to continuation c, passing only the top 0 <= p <= 15 values from the current stack to it (the remainder of the current stack is discarded).	26
DB2r	[r] RETARGS		Returns to c0, with 0 <= r <= 15 return values taken from the current stack.	26
DB30	RET RETTRUE		Returns to the continuation at c0. The remainder of the current continuation cc is discarded. Approximately equivalent to c0 PUSHCTR JMPX.	26
DB31	RETALT RETFALSE		Returns to the continuation at c1. Approximately equivalent to c1 PUSHCTR JMPX.	26
DB32	BRANCH RETBOOL	f -	Performs RETTRUE if integer f!=0, or RETFALSE if f=0.	26
DB34	CALLCC	c -	Call with current continuation, transfers control to c, pushing the old value of cc into c's stack (instead of discarding it or writing it into new c0).	26
DB35	JMPXDATA	c -	Similar to CALLCC, but the remainder of the current continuation (the old value of cc) is converted into a Slice before pushing it into the stack of c.	26
DB36pr	[p] [r] CALLCCARGS	c -	Similar to CALLXARGS, but pushes the old value of cc (along with the top 0 <= p <= 15 values from the original stack) into the stack of newly-invoked continuation c, setting cc.nargs to -1 <= r <= 14.	34
DB38	CALLXVARARGS	c p r -	Similar to CALLXARGS, but takes -1 <= p,r <= 254 from the stack. The next three operations also take p and r from the stack, both in the range -1...254.	26
DB39	RETVARARGS	p r -	Similar to RETARGS.	26
DB3A	JMPXVARARGS	c p r -	Similar to JMPXARGS.	26
DB3B	CALLCCVARARGS	c p r -	Similar to CALLCCARGS.	26
DB3C	[ref] CALLREF		Equivalent to PUSHREFCONT CALLX.	126/51
DB3D	[ref] JMPREF		Equivalent to PUSHREFCONT JMPX.	126/51
DB3E	[ref] JMPREFDATA		Equivalent to PUSHREFCONT JMPXDATA.	126/51
DB3F	RETDATA		Equivalent to c0 PUSHCTR JMPXDATA. In this way, the remainder of the current continuation is converted into a Slice and returned to the caller.	26

8.2 Conditional control flow primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
DC	IFRET IFNOT:	f -	Performs a RET, but only if integer f is non-zero. If f is a NaN, throws an integer overflow exception.	18
DD	IFNOTRET IF:	f -	Performs a RET, but only if integer f is zero.	18
DE	IF	f c -	Performs EXECUTE for c (i.e., executes c), but only if integer f is non-zero. Otherwise simply discards both values.	18
DE	IF:<{ code }> <{ code }>IF	f -	Equivalent to <{ code }> CONT IF.
DF	IFNOT	f c -	Executes continuation c, but only if integer f is zero. Otherwise simply discards both values.	18
DF	IFNOT:<{ code }> <{ code }>IFNOT	f -	Equivalent to <{ code }> CONT IFNOT.
E0	IFJMP	f c -	Jumps to c (similarly to JMPX), but only if f is non-zero.	18
E0	IFJMP:<{ code }>	f -	Equivalent to <{ code }> CONT IFJMP.
E1	IFNOTJMP	f c -	Jumps to c (similarly to JMPX), but only if f is zero.	18
E1	IFNOTJMP:<{ code }>	f -	Equivalent to <{ code }> CONT IFNOTJMP.
E2	IFELSE	f c c' -	If integer f is non-zero, executes c, otherwise executes c'. Equivalent to CONDSELCHK EXECUTE.	18
E2	IF:<{ code1 }>ELSE<{ code2 }>	f -	Equivalent to <{ code1 }> CONT <{ code2 }> CONT IFELSE.
E300	[ref] IFREF	f -	Equivalent to PUSHREFCONT IF, with the optimization that the cell reference is not actually loaded into a Slice and then converted into an ordinary Continuation if f=0. Gas consumption of this primitive depends on whether f=0 and whether the reference was loaded before. Similar remarks apply other primitives that accept a continuation as a reference.	26/126/51
E301	[ref] IFNOTREF	f -	Equivalent to PUSHREFCONT IFNOT.	26/126/51
E302	[ref] IFJMPREF	f -	Equivalent to PUSHREFCONT IFJMP.	26/126/51
E303	[ref] IFNOTJMPREF	f -	Equivalent to PUSHREFCONT IFNOTJMP.	26/126/51
E304	CONDSEL	f x y - x or y	If integer f is non-zero, returns x, otherwise returns y. Notice that no type checks are performed on x and y; as such, it is more like a conditional stack operation. Roughly equivalent to ROT ISZERO INC ROLLX NIP.	26
E305	CONDSELCHK	f x y - x or y	Same as CONDSEL, but first checks whether x and y have the same type.	26
E308	IFRETALT	f -	Performs RETALT if integer f!=0.	26
E309	IFNOTRETALT	f -	Performs RETALT if integer f=0.	26
E30D	[ref] IFREFELSE	f c -	Equivalent to PUSHREFCONT SWAP IFELSE, with the optimization that the cell reference is not actually loaded into a Slice and then converted into an ordinary Continuation if f=0. Similar remarks apply to the next two primitives: cells are converted into continuations only when necessary.	26/126/51
E30E	[ref] IFELSEREF	f c -	Equivalent to PUSHREFCONT IFELSE.	26/126/51
E30F	[ref] [ref] IFREFELSEREF	f -	Equivalent to PUSHREFCONT PUSHREFCONT IFELSE.	126/51
E39_n	[n] IFBITJMP	x c - x	Checks whether bit 0 <= n <= 31 is set in integer x, and if so, performs JMPX to continuation c. Value x is left in the stack.	26
E3B_n	[n] IFNBITJMP	x c - x	Jumps to c if bit 0 <= n <= 31 is not set in integer x.	26
E3D_n	[ref] [n] IFBITJMPREF	x - x	Performs a JMPREF if bit 0 <= n <= 31 is set in integer x.	126/51
E3F_n	[ref] [n] IFNBITJMPREF	x - x	Performs a JMPREF if bit 0 <= n <= 31 is not set in integer x.	126/51

8.3 Control flow primitives: loops

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
E4	REPEAT	n c -	Executes continuation c n times, if integer n is non-negative. If n>=2^31 or n<-2^31, generates a range check exception. Notice that a RET inside the code of c works as a continue, not as a break. One should use either alternative (experimental) loops or alternative RETALT (along with a SETEXITALT before the loop) to break out of a loop.	18
E4	REPEAT:<{ code }> <{ code }>REPEAT	n -	Equivalent to <{ code }> CONT REPEAT.
E5	REPEATEND REPEAT:	n -	Similar to REPEAT, but it is applied to the current continuation cc.	18
E6	UNTIL	c -	Executes continuation c, then pops an integer x from the resulting stack. If x is zero, performs another iteration of this loop. The actual implementation of this primitive involves an extraordinary continuation ec_until with its arguments set to the body of the loop (continuation c) and the original current continuation cc. This extraordinary continuation is then saved into the savelist of c as c.c0 and the modified c is then executed. The other loop primitives are implemented similarly with the aid of suitable extraordinary continuations.	18
E6	UNTIL:<{ code }> <{ code }>UNTIL	-	Equivalent to <{ code }> CONT UNTIL.
E7	UNTILEND UNTIL:	-	Similar to UNTIL, but executes the current continuation cc in a loop. When the loop exit condition is satisfied, performs a RET.	18
E8	WHILE	c' c -	Executes c' and pops an integer x from the resulting stack. If x is zero, exists the loop and transfers control to the original cc. If x is non-zero, executes c, and then begins a new iteration.	18
E8	WHILE:<{ cond }>DO<{ code }>	-	Equivalent to <{ cond }> CONT <{ code }> CONT WHILE.
E9	WHILEEND	c' -	Similar to WHILE, but uses the current continuation cc as the loop body.	18
EA	AGAIN	c -	Similar to REPEAT, but executes c infinitely many times. A RET only begins a new iteration of the infinite loop, which can be exited only by an exception, or a RETALT (or an explicit JMPX).	18
EA	AGAIN:<{ code }> <{ code }>AGAIN	-	Equivalent to <{ code }> CONT AGAIN.
EB	AGAINEND AGAIN:	-	Similar to AGAIN, but performed with respect to the current continuation cc.	18
E314	REPEATBRK	n c -	Similar to REPEAT, but also sets c1 to the original cc after saving the old value of c1 into the savelist of the original cc. In this way RETALT could be used to break out of the loop body.	26
E314	REPEATBRK:<{ code }> <{ code }>REPEATBRK	n -	Equivalent to <{ code }> CONT REPEATBRK.
E315	REPEATENDBRK	n -	Similar to REPEATEND, but also sets c1 to the original c0 after saving the old value of c1 into the savelist of the original c0. Equivalent to SAMEALTSAVE REPEATEND.	26
E316	UNTILBRK	c -	Similar to UNTIL, but also modifies c1 in the same way as REPEATBRK.	26
E316	UNTILBRK:<{ code }>	-	Equivalent to <{ code }> CONT UNTILBRK.
E317	UNTILENDBRK UNTILBRK:	-	Equivalent to SAMEALTSAVE UNTILEND.	26
E318	WHILEBRK	c' c -	Similar to WHILE, but also modifies c1 in the same way as REPEATBRK.	26
E318	WHILEBRK:<{ cond }>DO<{ code }>	-	Equivalent to <{ cond }> CONT <{ code }> CONT WHILEBRK.
E319	WHILEENDBRK	c -	Equivalent to SAMEALTSAVE WHILEEND.	26
E31A	AGAINBRK	c -	Similar to AGAIN, but also modifies c1 in the same way as REPEATBRK.	26
E31A	AGAINBRK:<{ code }>	-	Equivalent to <{ code }> CONT AGAINBRK.
E31B	AGAINENDBRK AGAINBRK:	-	Equivalent to SAMEALTSAVE AGAINEND.	26

8.4 Manipulating the stack of continuations

Here s" is the fee for moving stack elements between continuations. It is equal to the size of the resulting stack minus 32 (or 0 if the stack is smaller than 32).

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
ECrn	[r] [n] SETCONTARGS	x_1 x_2...x_r c - c'	Similar to [r] -1 SETCONTARGS, but sets c.nargs to the final size of the stack of c' plus n. In other words, transforms c into a closure or a partially applied function, with 0 <= n <= 14 arguments missing.	26+s”
EC0n	[n] SETNUMARGS	c - c'	Sets c.nargs to n plus the current depth of c's stack, where 0 <= n <= 14. If c.nargs is already set to a non-negative value, does nothing.	26
ECrF	[r] -1 SETCONTARGS	x_1 x_2...x_r c - c'	Pushes 0 <= r <= 15 values x_1...x_r into the stack of (a copy of) the continuation c, starting with x_1. If the final depth of c's stack turns out to be greater than c.nargs, a stack overflow exception is generated.	26+s”
ED0p	[p] RETURNARGS	-	Leaves only the top 0 <= p <= 15 values in the current stack (somewhat similarly to ONLYTOPX), with all the unused bottom values not discarded, but saved into continuation c0 in the same way as SETCONTARGS does.	26+s”
ED10	RETURNVARARGS	p -	Similar to RETURNARGS, but with Integer 0 <= p <= 255 taken from the stack.	26+s”
ED11	SETCONTVARARGS	x_1 x_2...x_r c r n - c'	Similar to SETCONTARGS, but with 0 <= r <= 255 and -1 <= n <= 255 taken from the stack.	26+s”
ED12	SETNUMVARARGS	c n - c'	-1 <= n <= 255 If n=-1, this operation does nothing (c'=c). Otherwise its action is similar to [n] SETNUMARGS, but with n taken from the stack.	26

8.5 Creating simple continuations and closures

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
ED1E	BLESS	s - c	Transforms a Slice s into a simple ordinary continuation c, with c.code=s and an empty stack and savelist.	26
ED1F	BLESSVARARGS	x_1...x_r s r n - c	Equivalent to ROT BLESS ROTREV SETCONTVARARGS.	26+s”
EErn	[r] [n] BLESSARGS	x_1...x_r s - c	0 <= r <= 15, -1 <= n <= 14 Equivalent to BLESS [r] [n] SETCONTARGS. The value of n is represented inside the instruction by the 4-bit integer n mod 16.	26
EE0n	[n] BLESSNUMARGS	s - c	Also transforms a Slice s into a Continuation c, but sets c.nargs to 0 <= n <= 14.	26

8.6 Operations with continuation savelists and control registers

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
ED4i	c[i] PUSHCTR c[i] PUSH	- x	Pushes the current value of control register c(i). If the control register is not supported in the current codepage, or if it does not have a value, an exception is triggered.	26
ED44	c4 PUSHCTR c4 PUSH	- x	Pushes the “global data root'' cell reference, thus enabling access to persistent smart-contract data.	26
ED5i	c[i] POPCTR c[i] POP	x -	Pops a value x from the stack and stores it into control register c(i), if supported in the current codepage. Notice that if a control register accepts only values of a specific type, a type-checking exception may occur.	26
ED54	c4 POPCTR c4 POP	x -	Sets the “global data root'' cell reference, thus allowing modification of persistent smart-contract data.	26
ED6i	c[i] SETCONT c[i] SETCONTCTR	x c - c'	Stores x into the savelist of continuation c as c(i), and returns the resulting continuation c'. Almost all operations with continuations may be expressed in terms of SETCONTCTR, POPCTR, and PUSHCTR.	26
ED7i	c[i] SETRETCTR	x -	Equivalent to c0 PUSHCTR c[i] SETCONTCTR c0 POPCTR.	26
ED8i	c[i] SETALTCTR	x -	Equivalent to c1 PUSHCTR c[i] SETCONTCTR c0 POPCTR.	26
ED9i	c[i] POPSAVE c[i] POPCTRSAVE	x -	Similar to c[i] POPCTR, but also saves the old value of c[i] into continuation c0. Equivalent (up to exceptions) to c[i] SAVECTR c[i] POPCTR.	26
EDAi	c[i] SAVE c[i] SAVECTR		Saves the current value of c(i) into the savelist of continuation c0. If an entry for c[i] is already present in the savelist of c0, nothing is done. Equivalent to c[i] PUSHCTR c[i] SETRETCTR.	26
EDBi	c[i] SAVEALT c[i] SAVEALTCTR		Similar to c[i] SAVE, but saves the current value of c[i] into the savelist of c1, not c0.	26
EDCi	c[i] SAVEBOTH c[i] SAVEBOTHCTR		Equivalent to DUP c[i] SAVE c[i] SAVEALT.	26
EDE0	PUSHCTRX	i - x	Similar to c[i] PUSHCTR, but with i, 0 <= i <= 255, taken from the stack. Notice that this primitive is one of the few “exotic'' primitives, which are not polymorphic like stack manipulation primitives, and at the same time do not have well-defined types of parameters and return values, because the type of x depends on i.	26
EDE1	POPCTRX	x i -	Similar to c[i] POPCTR, but with 0 <= i <= 255 from the stack.	26
EDE2	SETCONTCTRX	x c i - c'	Similar to c[i] SETCONTCTR, but with 0 <= i <= 255 from the stack.	26
EDF0	COMPOS BOOLAND	c c' - c''	Computes the composition compose0(c, c’), which has the meaning of “perform c, and, if successful, perform c''' (if c is a boolean circuit) or simply “perform c, then c'''. Equivalent to SWAP c0 SETCONT.	26
EDF1	COMPOSALT BOOLOR	c c' - c''	Computes the alternative composition compose1(c, c’), which has the meaning of “perform c, and, if not successful, perform c''' (if c is a boolean circuit). Equivalent to SWAP c1 SETCONT.	26
EDF2	COMPOSBOTH	c c' - c''	Computes composition compose1(compose0(c, c’), c’), which has the meaning of “compute boolean circuit c, then compute c', regardless of the result of c''.	26
EDF3	ATEXIT	c -	Sets c0 to compose0(c, c0). In other words, c will be executed before exiting current subroutine.	26
EDF3	ATEXIT:<{ code }> <{ code }>ATEXIT	-	Equivalent to <{ code }> CONT ATEXIT.
EDF4	ATEXITALT	c -	Sets c1 to compose1(c, c1). In other words, c will be executed before exiting current subroutine by its alternative return path.	26
EDF4	ATEXITALT:<{ code }> <{ code }>ATEXITALT	-	Equivalent to <{ code }> CONT ATEXITALT.
EDF5	SETEXITALT	c -	Sets c1 to compose1(compose0(c, c0), c1), In this way, a subsequent RETALT will first execute c, then transfer control to the original c0. This can be used, for instance, to exit from nested loops.	26
EDF6	THENRET	c - c'	Computes compose0(c, c0).	26
EDF7	THENRETALT	c - c'	Computes compose0(c, c1)	26
EDF8	INVERT	-	Interchanges c0 and c1.	26
EDF9	BOOLEVAL	c - ?	Performs cc:=compose1(compose0(c, compose0(-1 PUSHINT, cc)), compose0(0 PUSHINT, cc)). If c represents a boolean circuit, the net effect is to evaluate it and push either -1 or 0 into the stack before continuing.	26
EDFA	SAMEALT	-	Sets c1 to c0. Equivalent to c0 PUSHCTR c1 POPCTR.	26
EDFB	SAMEALTSAVE	-	Sets c1 to c0, but first saves the old value of c1 into the savelist of c0. Equivalent to c1 SAVE SAMEALT.	26

8.7 Dictionary subroutine calls and jumps

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F0nn	[nn] CALL [nn] CALLDICT	- nn	Calls the continuation in c3, pushing integer 0 <= nn <= 255 into its stack as an argument. Approximately equivalent to [nn] PUSHINT c3 PUSHCTR EXECUTE.
F12_n	[n] CALL [n] CALLDICT	- n	For 0 <= n < 2^14, an encoding of [n] CALL for larger values of n.
F16_n	[n] JMP	- n	Jumps to the continuation in c3, pushing integer 0 <= n < 2^14 as its argument. Approximately equivalent to n PUSHINT c3 PUSHCTR JMPX.
F1A_n	[n] PREPARE [n] PREPAREDICT	- n c	Equivalent to n PUSHINT c3 PUSHCTR, for 0 <= n < 2^14. In this way, [n] CALL is approximately equivalent to [n] PREPARE EXECUTE, and [n] JMP is approximately equivalent to [n] PREPARE JMPX. One might use, for instance, CALLXARGS or CALLCC instead of EXECUTE here.

9 Exception generating and handling primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F22_n	[n] THROW	- 0 n	Throws exception 0 <= n <= 63 with parameter zero. In other words, it transfers control to the continuation in c2, pushing 0 and n into its stack, and discarding the old stack altogether.	76
F26_n	[n] THROWIF	f -	Throws exception 0 <= n <= 63 with parameter zero only if integer f!=0.	26/76
F2A_n	[n] THROWIFNOT	f -	Throws exception 0 <= n <= 63 with parameter zero only if integer f=0.	26/76
F2C4_n	[n] THROW	- 0 nn	For 0 <= n < 2^11, an encoding of [n] THROW for larger values of n.	84
F2CC_n	[n] THROWARG	x - x nn	Throws exception 0 <= n < 2^11 with parameter x, by copying x and n into the stack of c2 and transferring control to c2.	84
F2D4_n	[n] THROWIF	f -	For 0 <= n < 2^11, an encoding of [n] THROWIF for larger values of n.	34/84
F2DC_n	[n] THROWARGIF	x f -	Throws exception 0 <= nn < 2^11 with parameter x only if integer f!=0.	34/84
F2E4_n	[n] THROWIFNOT	f -	For 0 <= n < 2^11, an encoding of [n] THROWIFNOT for larger values of n.	34/84
F2EC_n	[n] THROWARGIFNOT	x f -	Throws exception 0 <= n < 2^11 with parameter x only if integer f=0.	34/84
F2F0	THROWANY	n - 0 n	Throws exception 0 <= n < 2^16 with parameter zero. Approximately equivalent to ZERO SWAP THROWARGANY.	76
F2F1	THROWARGANY	x n - x n	Throws exception 0 <= n < 2^16 with parameter x, transferring control to the continuation in c2. Approximately equivalent to c2 PUSHCTR 2 JMPXARGS.	76
F2F2	THROWANYIF	n f -	Throws exception 0 <= n < 2^16 with parameter zero only if f!=0.	26/76
F2F3	THROWARGANYIF	x n f -	Throws exception 0 <= n<2^16 with parameter x only if f!=0.	26/76
F2F4	THROWANYIFNOT	n f -	Throws exception 0 <= n<2^16 with parameter zero only if f=0.	26/76
F2F5	THROWARGANYIFNOT	x n f -	Throws exception 0 <= n<2^16 with parameter x only if f=0.	26/76
F2FF	TRY	c c' -	Sets c2 to c', first saving the old value of c2 both into the savelist of c' and into the savelist of the current continuation, which is stored into c.c0 and c'.c0. Then runs c similarly to EXECUTE. If c does not throw any exceptions, the original value of c2 is automatically restored on return from c. If an exception occurs, the execution is transferred to c', but the original value of c2 is restored in the process, so that c' can re-throw the exception by THROWANY if it cannot handle it by itself.	26
F2FF	TRY:<{ code1 }>CATCH<{ code2 }>	-	Equivalent to <{ code1 }> CONT <{ code2 }> CONT TRY.
F3pr	[p] [r] TRYARGS	c c' -	Similar to TRY, but with [p] [r] CALLXARGS internally used instead of EXECUTE. In this way, all but the top 0 <= p <= 15 stack elements will be saved into current continuation's stack, and then restored upon return from either c or c', with the top 0 <= r <= 15 values of the resulting stack of c or c' copied as return values.	26

10 Dictionary manipulation primitives

The gas consumption of most dictionary operations is not fixed, it depends on the contents of the given dictionary.

10.1 Dictionary creation

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
6D	NEWDICT	- D	Returns a new empty dictionary. It is an alternative mnemonics for PUSHNULL.	18
6E	DICTEMPTY	D - ?	Checks whether dictionary D is empty, and returns -1 or 0 accordingly. It is an alternative mnemonics for ISNULL.	18

10.2 Dictionary serialization and deserialization

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
CE	STDICTS ``	s b - b'	Stores a Slice-represented dictionary s into Builder b. It is actually a synonym for STSLICE.	18
F400	STDICT STOPTREF	D b - b'	Stores dictionary D into Builder b, returing the resulting Builder b'. In other words, if D is a cell, performs STOSE and STREF; if D is Null, performs NIP and STZERO; otherwise throws a type checking exception.	26
F401	SKIPDICT SKIPOPTREF	s - s'	Equivalent to LDDICT NIP.	26
F402	LDDICTS	s - s' s''	Loads (parses) a (Slice-represented) dictionary s' from Slice s, and returns the remainder of s as s''. This is a “split function'' for all HashmapE(n,X) dictionary types.	26
F403	PLDDICTS	s - s'	Preloads a (Slice-represented) dictionary s' from Slice s. Approximately equivalent to LDDICTS DROP.	26
F404	LDDICT LDOPTREF	s - D s'	Loads (parses) a dictionary D from Slice s, and returns the remainder of s as s'. May be applied to dictionaries or to values of arbitrary (^Y)? types.	26
F405	PLDDICT PLDOPTREF	s - D	Preloads a dictionary D from Slice s. Approximately equivalent to LDDICT DROP.	26
F406	LDDICTQ	s - D s' -1 or s 0	A quiet version of LDDICT.	26
F407	PLDDICTQ	s - D -1 or 0	A quiet version of PLDDICT.	26

10.3 Get dictionary operations

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F40A	DICTGET	k D n - x -1 or 0	Looks up key k (represented by a Slice, the first 0 <= n <= 1023 data bits of which are used as a key) in dictionary D of type HashmapE(n,X) with n-bit keys. On success, returns the value found as a Slice x.
F40B	DICTGETREF	k D n - c -1 or 0	Similar to DICTGET, but with a LDREF ENDS applied to x on success. This operation is useful for dictionaries of type HashmapE(n,^Y).
F40C	DICTIGET	i D n - x -1 or 0	Similar to DICTGET, but with a signed (big-endian) n-bit Integer i as a key. If i does not fit into n bits, returns 0. If i is a NaN, throws an integer overflow exception.
F40D	DICTIGETREF	i D n - c -1 or 0	Combines DICTIGET with DICTGETREF: it uses signed n-bit Integer i as a key and returns a Cell instead of a Slice on success.
F40E	DICTUGET	i D n - x -1 or 0	Similar to DICTIGET, but with unsigned (big-endian) n-bit Integer i used as a key.
F40F	DICTUGETREF	i D n - c -1 or 0	Similar to DICTIGETREF, but with an unsigned n-bit Integer key i.

10.4 Set/Replace/Add dictionary operations

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F412	DICTSET	x k D n - D'	Sets the value associated with n-bit key k (represented by a Slice as in DICTGET) in dictionary D (also represented by a Slice) to value x (again a Slice), and returns the resulting dictionary as D'.
F413	DICTSETREF	c k D n - D'	Similar to DICTSET, but with the value set to a reference to Cell c.
F414	DICTISET	x i D n - D'	Similar to DICTSET, but with the key represented by a (big-endian) signed n-bit integer i. If i does not fit into n bits, a range check exception is generated.
F415	DICTISETREF	c i D n - D'	Similar to DICTSETREF, but with the key a signed n-bit integer as in DICTISET.
F416	DICTUSET	x i D n - D'	Similar to DICTISET, but with i an unsigned n-bit integer.
F417	DICTUSETREF	c i D n - D'	Similar to DICTISETREF, but with i unsigned.
F41A	DICTSETGET	x k D n - D' y -1 or D' 0	Combines DICTSET with DICTGET: it sets the value corresponding to key k to x, but also returns the old value y associated with the key in question, if present.
F41B	DICTSETGETREF	c k D n - D' c' -1 or D' 0	Combines DICTSETREF with DICTGETREF similarly to DICTSETGET.
F41C	DICTISETGET	x i D n - D' y -1 or D' 0	DICTISETGET, but with i a signed n-bit integer.
F41D	DICTISETGETREF	c i D n - D' c' -1 or D' 0	DICTISETGETREF, but with i a signed n-bit integer.
F41E	DICTUSETGET	x i D n - D' y -1 or D' 0	DICTISETGET, but with i an unsigned n-bit integer.
F41F	DICTUSETGETREF	c i D n - D' c' -1 or D' 0	DICTISETGETREF, but with i an unsigned n-bit integer.
F422	DICTREPLACE	x k D n - D' -1 or D 0	A Replace operation, which is similar to DICTSET, but sets the value of key k in dictionary D to x only if the key k was already present in D.
F423	DICTREPLACEREF	c k D n - D' -1 or D 0	A Replace counterpart of DICTSETREF.
F424	DICTIREPLACE	x i D n - D' -1 or D 0	DICTREPLACE, but with i a signed n-bit integer.
F425	DICTIREPLACEREF	c i D n - D' -1 or D 0	DICTREPLACEREF, but with i a signed n-bit integer.
F426	DICTUREPLACE	x i D n - D' -1 or D 0	DICTREPLACE, but with i an unsigned n-bit integer.
F427	DICTUREPLACEREF	c i D n - D' -1 or D 0	DICTREPLACEREF, but with i an unsigned n-bit integer.
F42A	DICTREPLACEGET	x k D n - D' y -1 or D 0	A Replace counterpart of DICTSETGET: on success, also returns the old value associated with the key in question.
F42B	DICTREPLACEGETREF	c k D n - D' c' -1 or D 0	A Replace counterpart of DICTSETGETREF.
F42C	DICTIREPLACEGET	x i D n - D' y -1 or D 0	DICTREPLACEGET, but with i a signed n-bit integer.
F42D	DICTIREPLACEGETREF	c i D n - D' c' -1 or D 0	DICTREPLACEGETREF, but with i a signed n-bit integer.
F42E	DICTUREPLACEGET	x i D n - D' y -1 or D 0	DICTREPLACEGET, but with i an unsigned n-bit integer.
F42F	DICTUREPLACEGETREF	c i D n - D' c' -1 or D 0	DICTREPLACEGETREF, but with i an unsigned n-bit integer.
F432	DICTADD	x k D n - D' -1 or D 0	An Add counterpart of DICTSET: sets the value associated with key k in dictionary D to x, but only if it is not already present in D.
F433	DICTADDREF	c k D n - D' -1 or D 0	An Add counterpart of DICTSETREF.
F434	DICTIADD	x i D n - D' -1 or D 0	DICTADD, but with i a signed n-bit integer.
F435	DICTIADDREF	c i D n - D' -1 or D 0	DICTADDREF, but with i a signed n-bit integer.
F436	DICTUADD	x i D n - D' -1 or D 0	DICTADD, but with i an unsigned n-bit integer.
F437	DICTUADDREF	c i D n - D' -1 or D 0	DICTADDREF, but with i an unsigned n-bit integer.
F43A	DICTADDGET	x k D n - D' -1 or D y 0	An Add counterpart of DICTSETGET: sets the value associated with key k in dictionary D to x, but only if key k is not already present in D. Otherwise, just returns the old value y without changing the dictionary.
F43B	DICTADDGETREF	c k D n - D' -1 or D c' 0	An Add counterpart of DICTSETGETREF.
F43C	DICTIADDGET	x i D n - D' -1 or D y 0	DICTADDGET, but with i a signed n-bit integer.
F43D	DICTIADDGETREF	c i D n - D' -1 or D c' 0	DICTADDGETREF, but with i a signed n-bit integer.
F43E	DICTUADDGET	x i D n - D' -1 or D y 0	DICTADDGET, but with i an unsigned n-bit integer.
F43F	DICTUADDGETREF	c i D n - D' -1 or D c' 0	DICTADDGETREF, but with i an unsigned n-bit integer.

10.5 Builder-accepting variants of Set dictionary operations

The following primitives accept the new value as a Builder b instead of a Slice x.

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F441	DICTSETB	b k D n - D'
F442	DICTISETB	b i D n - D'
F443	DICTUSETB	b i D n - D'
F445	DICTSETGETB	b k D n - D' y -1 or D' 0
F446	DICTISETGETB	b i D n - D' y -1 or D' 0
F447	DICTUSETGETB	b i D n - D' y -1 or D' 0
F449	DICTREPLACEB	b k D n - D' -1 or D 0
F44A	DICTIREPLACEB	b i D n - D' -1 or D 0
F44B	DICTUREPLACEB	b i D n - D' -1 or D 0
F44D	DICTREPLACEGETB	b k D n - D' y -1 or D 0
F44E	DICTIREPLACEGETB	b i D n - D' y -1 or D 0
F44F	DICTUREPLACEGETB	b i D n - D' y -1 or D 0
F451	DICTADDB	b k D n - D' -1 or D 0
F452	DICTIADDB	b i D n - D' -1 or D 0
F453	DICTUADDB	b i D n - D' -1 or D 0
F455	DICTADDGETB	b k D n - D' -1 or D y 0
F456	DICTIADDGETB	b i D n - D' -1 or D y 0
F457	DICTUADDGETB	b i D n - D' -1 or D y 0

10.6 Delete dictionary operations

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F459	DICTDEL	k D n - D' -1 or D 0	Deletes n-bit key, represented by a Slice k, from dictionary D. If the key is present, returns the modified dictionary D' and the success flag -1. Otherwise, returns the original dictionary D and 0.
F45A	DICTIDEL	i D n - D' ?	A version of DICTDEL with the key represented by a signed n-bit Integer i. If i does not fit into n bits, simply returns D 0 (“key not found, dictionary unmodified'').
F45B	DICTUDEL	i D n - D' ?	Similar to DICTIDEL, but with i an unsigned n-bit integer.
F462	DICTDELGET	k D n - D' x -1 or D 0	Deletes n-bit key, represented by a Slice k, from dictionary D. If the key is present, returns the modified dictionary D', the original value x associated with the key k (represented by a Slice), and the success flag -1. Otherwise, returns the original dictionary D and 0.
F463	DICTDELGETREF	k D n - D' c -1 or D 0	Similar to DICTDELGET, but with LDREF ENDS applied to x on success, so that the value returned c is a Cell.
F464	DICTIDELGET	i D n - D' x -1 or D 0	DICTDELGET, but with i a signed n-bit integer.
F465	DICTIDELGETREF	i D n - D' c -1 or D 0	DICTDELGETREF, but with i a signed n-bit integer.
F466	DICTUDELGET	i D n - D' x -1 or D 0	DICTDELGET, but with i an unsigned n-bit integer.
F467	DICTUDELGETREF	i D n - D' c -1 or D 0	DICTDELGETREF, but with i an unsigned n-bit integer.

10.7 "Maybe reference" dictionary operations

The following operations assume that a dictionary is used to store values c? of type Maybe Cell. The representation is as follows: if c? is a Cell , it is stored as a value with no data bits and exactly one reference to this Cell. If c? is Null, then the corresponding key must be absent from the dictionary.

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F469	DICTGETOPTREF	k D n - c^?	A variant of DICTGETREF that returns Null instead of the value c^? if the key k is absent from dictionary D.
F46A	DICTIGETOPTREF	i D n - c^?	DICTGETOPTREF, but with i a signed n-bit integer. If the key i is out of range, also returns Null.
F46B	DICTUGETOPTREF	i D n - c^?	DICTGETOPTREF, but with i an unsigned n-bit integer. If the key i is out of range, also returns Null.
F46D	DICTSETGETOPTREF	c^? k D n - D' ~c^?	A variant of both DICTGETOPTREF and DICTSETGETREF that sets the value corresponding to key k in dictionary D to c^? (if c^? is Null, then the key is deleted instead), and returns the old value ~c^? (if the key k was absent before, returns Null instead).
F46E	DICTISETGETOPTREF	c^? i D n - D' ~c^?	Similar to primitive DICTSETGETOPTREF, but using signed n-bit Integer i as a key. If i does not fit into n bits, throws a range checking exception.
F46F	DICTUSETGETOPTREF	c^? i D n - D' ~c^?	Similar to primitive DICTSETGETOPTREF, but using unsigned n-bit Integer i as a key.

10.8 Prefix code dictionary operations

These are some basic operations for constructing prefix code dictionaries. These primitives are completely similar to their non-prefix code counterparts (DICTSET etc), with the obvious difference that even a Set may fail in a prefix code dictionary, so a success flag must be returned by PFXDICTSET as well.

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F470	PFXDICTSET	x k D n - D' -1 or D 0
F471	PFXDICTREPLACE	x k D n - D' -1 or D 0
F472	PFXDICTADD	x k D n - D' -1 or D 0
F473	PFXDICTDEL	k D n - D' -1 or D 0

10.9 Variants of GetNext and GetPrev operations

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F474	DICTGETNEXT	k D n - x' k' -1 or 0	Computes the minimal key k' in dictionary D that is lexicographically greater than k, and returns k' (represented by a Slice) along with associated value x' (also represented by a Slice).
F475	DICTGETNEXTEQ	k D n - x' k' -1 or 0	Similar to DICTGETNEXT, but computes the minimal key k' that is lexicographically greater than or equal to k.
F476	DICTGETPREV	k D n - x' k' -1 or 0	Similar to DICTGETNEXT, but computes the maximal key k' lexicographically smaller than k.
F477	DICTGETPREVEQ	k D n - x' k' -1 or 0	Similar to DICTGETPREV, but computes the maximal key k' lexicographically smaller than or equal to k.
F478	DICTIGETNEXT	i D n - x' i' -1 or 0	Similar to DICTGETNEXT, but interprets all keys in dictionary D as big-endian signed n-bit integers, and computes the minimal key i' that is larger than Integer i (which does not necessarily fit into n bits).
F479	DICTIGETNEXTEQ	i D n - x' i' -1 or 0	Similar to DICTGETNEXTEQ, but interprets keys as signed n-bit integers.
F47A	DICTIGETPREV	i D n - x' i' -1 or 0	Similar to DICTGETPREV, but interprets keys as signed n-bit integers.
F47B	DICTIGETPREVEQ	i D n - x' i' -1 or 0	Similar to DICTGETPREVEQ, but interprets keys as signed n-bit integers.
F47C	DICTUGETNEXT	i D n - x' i' -1 or 0	Similar to DICTGETNEXT, but interprets all keys in dictionary D as big-endian unsigned n-bit integers, and computes the minimal key i' that is larger than Integer i (which does not necessarily fit into n bits, and is not necessarily non-negative).
F47D	DICTUGETNEXTEQ	i D n - x' i' -1 or 0	Similar to DICTGETNEXTEQ, but interprets keys as unsigned n-bit integers.
F47E	DICTUGETPREV	i D n - x' i' -1 or 0	Similar to DICTGETPREV, but interprets keys as unsigned n-bit integers.
F47F	DICTUGETPREVEQ	i D n - x' i' -1 or 0	Similar to DICTGETPREVEQ, but interprets keys a unsigned n-bit integers.

10.10 GetMin, GetMax, RemoveMin, RemoveMax operations

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F482	DICTMIN	D n - x k -1 or 0	Computes the minimal key k (represented by a Slice with n data bits) in dictionary D, and returns k along with the associated value x.
F483	DICTMINREF	D n - c k -1 or 0	Similar to DICTMIN, but returns the only reference in the value as a Cell c.
F484	DICTIMIN	D n - x i -1 or 0	Similar to DICTMIN, but computes the minimal key i under the assumption that all keys are big-endian signed n-bit integers. Notice that the key and value returned may differ from those computed by DICTMIN and DICTUMIN.
F485	DICTIMINREF	D n - c i -1 or 0	Similar to DICTIMIN, but returns the only reference in the value.
F486	DICTUMIN	D n - x i -1 or 0	Similar to DICTMIN, but returns the key as an unsigned n-bit Integer i.
F487	DICTUMINREF	D n - c i -1 or 0	Similar to DICTUMIN, but returns the only reference in the value.
F48A	DICTMAX	D n - x k -1 or 0	Computes the maximal key k (represented by a Slice with n data bits) in dictionary D, and returns k along with the associated value x.
F48B	DICTMAXREF	D n - c k -1 or 0	Similar to DICTMAX, but returns the only reference in the value.
F48C	DICTIMAX	D n - x i -1 or 0	Similar to DICTMAX, but computes the maximal key i under the assumption that all keys are big-endian signed n-bit integers. Notice that the key and value returned may differ from those computed by DICTMAX and DICTUMAX.
F48D	DICTIMAXREF	D n - c i -1 or 0	Similar to DICTIMAX, but returns the only reference in the value.
F48E	DICTUMAX	D n - x i -1 or 0	Similar to DICTMAX, but returns the key as an unsigned n-bit Integer i.
F48F	DICTUMAXREF	D n - c i -1 or 0	Similar to DICTUMAX, but returns the only reference in the value.
F492	DICTREMMIN	D n - D' x k -1 or D 0	Computes the minimal key k (represented by a Slice with n data bits) in dictionary D, removes k from the dictionary, and returns k along with the associated value x and the modified dictionary D'.
F493	DICTREMMINREF	D n - D' c k -1 or D 0	Similar to DICTREMMIN, but returns the only reference in the value as a Cell c.
F494	DICTIREMMIN	D n - D' x i -1 or D 0	Similar to DICTREMMIN, but computes the minimal key i under the assumption that all keys are big-endian signed n-bit integers. Notice that the key and value returned may differ from those computed by DICTREMMIN and DICTUREMMIN.
F495	DICTIREMMINREF	D n - D' c i -1 or D 0	Similar to DICTIREMMIN, but returns the only reference in the value.
F496	DICTUREMMIN	D n - D' x i -1 or D 0	Similar to DICTREMMIN, but returns the key as an unsigned n-bit Integer i.
F497	DICTUREMMINREF	D n - D' c i -1 or D 0	Similar to DICTUREMMIN, but returns the only reference in the value.
F49A	DICTREMMAX	D n - D' x k -1 or D 0	Computes the maximal key k (represented by a Slice with n data bits) in dictionary D, removes k from the dictionary, and returns k along with the associated value x and the modified dictionary D'.
F49B	DICTREMMAXREF	D n - D' c k -1 or D 0	Similar to DICTREMMAX, but returns the only reference in the value as a Cell c.
F49C	DICTIREMMAX	D n - D' x i -1 or D 0	Similar to DICTREMMAX, but computes the minimal key i under the assumption that all keys are big-endian signed n-bit integers. Notice that the key and value returned may differ from those computed by DICTREMMAX and DICTUREMMAX.
F49D	DICTIREMMAXREF	D n - D' c i -1 or D 0	Similar to DICTIREMMAX, but returns the only reference in the value.
F49E	DICTUREMMAX	D n - D' x i -1 or D 0	Similar to DICTREMMAX, but returns the key as an unsigned n-bit Integer i.
F49F	DICTUREMMAXREF	D n - D' c i -1 or D 0	Similar to DICTUREMMAX, but returns the only reference in the value.

10.11 Special Get dictionary and prefix code dictionary operations and constant dictionaries

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F4A0	DICTIGETJMP	i D n -	Similar to DICTIGET, but with x BLESSed into a continuation with a subsequent JMPX to it on success. On failure, does nothing. This is useful for implementing switch/case constructions.
F4A1	DICTUGETJMP	i D n -	Similar to DICTIGETJMP, but performs DICTUGET instead of DICTIGET.
F4A2	DICTIGETEXEC	i D n -	Similar to DICTIGETJMP, but with EXECUTE instead of JMPX.
F4A3	DICTUGETEXEC	i D n -	Similar to DICTUGETJMP, but with EXECUTE instead of JMPX.
F4A6_n	[ref] [n] DICTPUSHCONST	- D n	Pushes a non-empty constant dictionary D (as a Cell^?) along with its key length 0 <= n <= 1023, stored as a part of the instruction. The dictionary itself is created from the first of remaining references of the current continuation. In this way, the complete DICTPUSHCONST instruction can be obtained by first serializing xF4A4_, then the non-empty dictionary itself (one 1 bit and a cell reference), and then the unsigned 10-bit integer n (as if by a STU 10 instruction). An empty dictionary can be pushed by a NEWDICT primitive instead.	34
F4A8	PFXDICTGETQ	s D n - s' x s'' -1 or s 0	Looks up the unique prefix of Slice s present in the prefix code dictionary represented by Cell^? D and 0 <= n <= 1023. If found, the prefix of s is returned as s', and the corresponding value (also a Slice) as x. The remainder of s is returned as a Slice s''. If no prefix of s is a key in prefix code dictionary D, returns the unchanged s and a zero flag to indicate failure.
F4A9	PFXDICTGET	s D n - s' x s''	Similar to PFXDICTGET, but throws a cell deserialization failure exception on failure.
F4AA	PFXDICTGETJMP	s D n - s' s'' or s	Similar to PFXDICTGETQ, but on success BLESSes the value x into a Continuation and transfers control to it as if by a JMPX. On failure, returns s unchanged and continues execution.
F4AB	PFXDICTGETEXEC	s D n - s' s''	Similar to PFXDICTGETJMP, but EXECutes the continuation found instead of jumping to it. On failure, throws a cell deserialization exception.
F4AE_n	[ref] [n] PFXDICTCONSTGETJMP [ref] [n] PFXDICTSWITCH	s - s' s'' or s	Combines [n] DICTPUSHCONST for 0 <= n <= 1023 with PFXDICTGETJMP.
F4BC	DICTIGETJMPZ	i D n - i or nothing	A variant of DICTIGETJMP that returns index i on failure.
F4BD	DICTUGETJMPZ	i D n - i or nothing	A variant of DICTUGETJMP that returns index i on failure.
F4BE	DICTIGETEXECZ	i D n - i or nothing	A variant of DICTIGETEXEC that returns index i on failure.
F4BF	DICTUGETEXECZ	i D n - i or nothing	A variant of DICTUGETEXEC that returns index i on failure.

10.12 SubDict dictionary operations

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F4B1	SUBDICTGET	k l D n - D'	Constructs a subdictionary consisting of all keys beginning with prefix k (represented by a Slice, the first 0 <= l <= n <= 1023 data bits of which are used as a key) of length l in dictionary D of type HashmapE(n,X) with n-bit keys. On success, returns the new subdictionary of the same type HashmapE(n,X) as a Slice D'.
F4B2	SUBDICTIGET	x l D n - D'	Variant of SUBDICTGET with the prefix represented by a signed big-endian l-bit Integer x, where necessarily l <= 257.
F4B3	SUBDICTUGET	x l D n - D'	Variant of SUBDICTGET with the prefix represented by an unsigned big-endian l-bit Integer x, where necessarily l <= 256.
F4B5	SUBDICTRPGET	k l D n - D'	Similar to SUBDICTGET, but removes the common prefix k from all keys of the new dictionary D', which becomes of type HashmapE(n-l,X).
F4B6	SUBDICTIRPGET	x l D n - D'	Variant of SUBDICTRPGET with the prefix represented by a signed big-endian l-bit Integer x, where necessarily l <= 257.
F4B7	SUBDICTURPGET	x l D n - D'	Variant of SUBDICTRPGET with the prefix represented by an unsigned big-endian l-bit Integer x, where necessarily l <= 256.

11 Application-specific primitives

11.1 Gas-related primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F800	ACCEPT	-	Sets current gas limit g_l to its maximal allowed value g_m, and resets the gas credit g_c to zero, decreasing the value of g_r by g_c in the process. In other words, the current smart contract agrees to buy some gas to finish the current transaction. This action is required to process external messages, which bring no value (hence no gas) with themselves.	26
F801	SETGASLIMIT	g -	Sets current gas limit g_l to the minimum of g and g_m, and resets the gas credit g_c to zero. If the gas consumed so far (including the present instruction) exceeds the resulting value of g_l, an (unhandled) out of gas exception is thrown before setting new gas limits. Notice that SETGASLIMIT with an argument g >= 2^63-1 is equivalent to ACCEPT.	26
F80F	COMMIT	-	Commits the current state of registers c4 (“persistent data'') and c5 (“actions'') so that the current execution is considered “successful'' with the saved values even if an exception is thrown later.	26

11.2 Pseudo-random number generator primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F810	RANDU256	- x	Generates a new pseudo-random unsigned 256-bit Integer x. The algorithm is as follows: if r is the old value of the random seed, considered as a 32-byte array (by constructing the big-endian representation of an unsigned 256-bit integer), then its sha512(r) is computed; the first 32 bytes of this hash are stored as the new value r' of the random seed, and the remaining 32 bytes are returned as the next random value x.	26+\|c7\|+\|c1_1\|
F811	RAND	y - z	Generates a new pseudo-random integer z in the range 0...y-1 (or y...-1, if y<0). More precisely, an unsigned random value x is generated as in RAND256U; then z:=floor(x*y/2^256) is computed. Equivalent to RANDU256 256 MULRSHIFT.	26+\|c7\|+\|c1_1\|
F814	SETRAND	x -	Sets the random seed to unsigned 256-bit Integer x.	26+\|c7\|+\|c1_1\|
F815	ADDRAND RANDOMIZE	x -	Mixes unsigned 256-bit Integer x into the random seed r by setting the random seed to Sha of the concatenation of two 32-byte strings: the first with the big-endian representation of the old seed r, and the second with the big-endian representation of x.	26

11.3 Configuration primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F82i	[i] GETPARAM	- x	Returns the i-th parameter from the Tuple provided at c7 for 0 <= i <= 15. Equivalent to c7 PUSHCTR FIRST [i] INDEX. If one of these internal operations fails, throws an appropriate type checking or range checking exception.	26
F823	NOW	- x	Returns the current Unix time as an Integer. If it is impossible to recover the requested value starting from c7, throws a type checking or range checking exception as appropriate. Equivalent to 3 GETPARAM.	26
F824	BLOCKLT	- x	Returns the starting logical time of the current block. Equivalent to 4 GETPARAM.	26
F825	LTIME	- x	Returns the logical time of the current transaction. Equivalent to 5 GETPARAM.	26
F826	RANDSEED	- x	Returns the current random seed as an unsigned 256-bit Integer. Equivalent to 6 GETPARAM.	26
F827	BALANCE	- t	Returns the remaining balance of the smart contract as a Tuple consisting of an Integer (the remaining Gram balance in nanograms) and a Maybe Cell (a dictionary with 32-bit keys representing the balance of “extra currencies''). Equivalent to 7 GETPARAM. Note that RAW primitives such as SENDRAWMSG do not update this field.	26
F828	MYADDR	- s	Returns the internal address of the current smart contract as a Slice with a MsgAddressInt. If necessary, it can be parsed further using primitives such as PARSEMSGADDR or REWRITESTDADDR. Equivalent to 8 GETPARAM.	26
F829	CONFIGROOT	- D	Returns the Maybe Cell D with the current global configuration dictionary. Equivalent to 9 GETPARAM .	26
F830	CONFIGDICT	- D 32	Returns the global configuration dictionary along with its key length (32). Equivalent to CONFIGROOT 32 PUSHINT.	26
F832	CONFIGPARAM	i - c -1 or 0	Returns the value of the global configuration parameter with integer index i as a Cell c, and a flag to indicate success. Equivalent to CONFIGDICT DICTIGETREF.
F833	CONFIGOPTPARAM	i - c^?	Returns the value of the global configuration parameter with integer index i as a Maybe Cell c^?. Equivalent to CONFIGDICT DICTIGETOPTREF.

11.4 Global variable primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F840	GETGLOBVAR	k - x	Returns the k-th global variable for 0 <= k < 255. Equivalent to c7 PUSHCTR SWAP INDEXVARQ.	26
F85_k	[k] GETGLOB	- x	Returns the k-th global variable for 1 <= k <= 31. Equivalent to c7 PUSHCTR [k] INDEXQ.	26
F860	SETGLOBVAR	x k -	Assigns x to the k-th global variable for 0 <= k < 255. Equivalent to c7 PUSHCTR ROTREV SETINDEXVARQ c7 POPCTR.	26+\|c7’\|
F87_k	[k] SETGLOB	x -	Assigns x to the k-th global variable for 1 <= k <= 31. Equivalent to c7 PUSHCTR SWAP k SETINDEXQ c7 POPCTR.	26+\|c7’\|

11.5 Hashing and cryptography primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F900	HASHCU	c - x	Computes the representation hash of a Cell c and returns it as a 256-bit unsigned integer x. Useful for signing and checking signatures of arbitrary entities represented by a tree of cells.	26
F901	HASHSU	s - x	Computes the hash of a Slice s and returns it as a 256-bit unsigned integer x. The result is the same as if an ordinary cell containing only data and references from s had been created and its hash computed by HASHCU.	526
F902	SHA256U	s - x	Computes Sha of the data bits of Slice s. If the bit length of s is not divisible by eight, throws a cell underflow exception. The hash value is returned as a 256-bit unsigned integer x.	26
F910	CHKSIGNU	h s k - ?	Checks the Ed25519-signature s of a hash h (a 256-bit unsigned integer, usually computed as the hash of some data) using public key k (also represented by a 256-bit unsigned integer). The signature s must be a Slice containing at least 512 data bits; only the first 512 bits are used. The result is -1 if the signature is valid, 0 otherwise. Notice that CHKSIGNU is equivalent to ROT NEWC 256 STU ENDC ROTREV CHKSIGNS, i.e., to CHKSIGNS with the first argument d set to 256-bit Slice containing h. Therefore, if h is computed as the hash of some data, these data are hashed twice, the second hashing occurring inside CHKSIGNS.	26
F911	CHKSIGNS	d s k - ?	Checks whether s is a valid Ed25519-signature of the data portion of Slice d using public key k, similarly to CHKSIGNU. If the bit length of Slice d is not divisible by eight, throws a cell underflow exception. The verification of Ed25519 signatures is the standard one, with Sha used to reduce d to the 256-bit number that is actually signed.	26

11.6 Miscellaneous primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
F940	CDATASIZEQ	c n - x y z -1 or 0	Recursively computes the count of distinct cells x, data bits y, and cell references z in the dag rooted at Cell c, effectively returning the total storage used by this dag taking into account the identification of equal cells. The values of x, y, and z are computed by a depth-first traversal of this dag, with a hash table of visited cell hashes used to prevent visits of already-visited cells. The total count of visited cells x cannot exceed non-negative Integer n; otherwise the computation is aborted before visiting the (n+1)-st cell and a zero is returned to indicate failure. If c is Null, returns x=y=z=0.
F941	CDATASIZE	c n - x y z	A non-quiet version of CDATASIZEQ that throws a cell overflow exception (8) on failure.
F942	SDATASIZEQ	s n - x y z -1 or 0	Similar to CDATASIZEQ, but accepting a Slice s instead of a Cell. The returned value of x does not take into account the cell that contains the slice s itself; however, the data bits and the cell references of s are accounted for in y and z.
F943	SDATASIZE	s n - x y z	A non-quiet version of SDATASIZEQ that throws a cell overflow exception (8) on failure.

11.7 Currency manipulation primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
FA00	LDGRAMS LDVARUINT16	s - x s'	Loads (deserializes) a Gram or VarUInteger 16 amount from Slice s, and returns the amount as Integer x along with the remainder s' of s. The expected serialization of x consists of a 4-bit unsigned big-endian integer l, followed by an 8l-bit unsigned big-endian representation of x. The net effect is approximately equivalent to 4 LDU SWAP 3 LSHIFT# LDUX.	26
FA01	LDVARINT16	s - x s'	Similar to LDVARUINT16, but loads a signed Integer x. Approximately equivalent to 4 LDU SWAP 3 LSHIFT# LDIX.	26
FA02	STGRAMS STVARUINT16	b x - b'	Stores (serializes) an Integer x in the range 0...2^120-1 into Builder b, and returns the resulting Builder b'. The serialization of x consists of a 4-bit unsigned big-endian integer l, which is the smallest integer l>=0, such that x<2^(8l), followed by an 8l-bit unsigned big-endian representation of x. If x does not belong to the supported range, a range check exception is thrown.	26
FA03	STVARINT16	b x - b'	Similar to STVARUINT16, but serializes a signed Integer x in the range -2^119...2^119-1.	26

11.8 Message and address manipulation primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
FA40	LDMSGADDR	s - s' s''	Loads from Slice s the only prefix that is a valid MsgAddress, and returns both this prefix s' and the remainder s'' of s as slices.	26
FA41	LDMSGADDRQ	s - s' s'' -1 or s 0	A quiet version of LDMSGADDR: on success, pushes an extra -1; on failure, pushes the original s and a zero.	26
FA42	PARSEMSGADDR	s - t	Decomposes Slice s containing a valid MsgAddress into a Tuple t with separate fields of this MsgAddress. If s is not a valid MsgAddress, a cell deserialization exception is thrown.	26
FA43	PARSEMSGADDRQ	s - t -1 or 0	A quiet version of PARSEMSGADDR: returns a zero on error instead of throwing an exception.	26
FA44	REWRITESTDADDR	s - x y	Parses Slice s containing a valid MsgAddressInt (usually a msg_addr_std), applies rewriting from the anycast (if present) to the same-length prefix of the address, and returns both the workchain x and the 256-bit address y as integers. If the address is not 256-bit, or if s is not a valid serialization of MsgAddressInt, throws a cell deserialization exception.	26
FA45	REWRITESTDADDRQ	s - x y -1 or 0	A quiet version of primitive REWRITESTDADDR.	26
FA46	REWRITEVARADDR	s - x s'	A variant of REWRITESTDADDR that returns the (rewritten) address as a Slice s, even if it is not exactly 256 bit long (represented by a msg_addr_var).	26
FA47	REWRITEVARADDRQ	s - x s' -1 or 0	A quiet version of primitive REWRITEVARADDR.	26

11.9 Outbound message and output action primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
FB00	SENDRAWMSG	c x -	Sends a raw message contained in Cell c, which should contain a correctly serialized object Message X, with the only exception that the source address is allowed to have dummy value addr_none (to be automatically replaced with the current smart-contract address), and ihr_fee, fwd_fee, created_lt and created_at fields can have arbitrary values (to be rewritten with correct values during the action phase of the current transaction). Integer parameter x contains the flags. Currently x=0 is used for ordinary messages; x=128 is used for messages that are to carry all the remaining balance of the current smart contract (instead of the value originally indicated in the message); x=64 is used for messages that carry all the remaining value of the inbound message in addition to the value initially indicated in the new message (if bit 0 is not set, the gas fees are deducted from this amount); x'=x+1 means that the sender wants to pay transfer fees separately; x'=x+2 means that any errors arising while processing this message during the action phase should be ignored. Finally, x'=x+32 means that the current account must be destroyed if its resulting balance is zero. This flag is usually employed together with +128.	526
FB02	RAWRESERVE	x y -	Creates an output action which would reserve exactly x nanograms (if y=0), at most x nanograms (if y=2), or all but x nanograms (if y=1 or y=3), from the remaining balance of the account. It is roughly equivalent to creating an outbound message carrying x nanograms (or b-x nanograms, where b is the remaining balance) to oneself, so that the subsequent output actions would not be able to spend more money than the remainder. Bit +2 in y means that the external action does not fail if the specified amount cannot be reserved; instead, all remaining balance is reserved. Bit +8 in y means x:=-x before performing any further actions. Bit +4 in y means that x is increased by the original balance of the current account (before the compute phase), including all extra currencies, before performing any other checks and actions. Currently x must be a non-negative integer, and y must be in the range 0...15.	526
FB03	RAWRESERVEX	x D y -	Similar to RAWRESERVE, but also accepts a dictionary D (represented by a Cell or Null) with extra currencies. In this way currencies other than Grams can be reserved.	526
FB04	SETCODE	c -	Creates an output action that would change this smart contract code to that given by Cell c. Notice that this change will take effect only after the successful termination of the current run of the smart contract.	526
FB06	SETLIBCODE	c x -	Creates an output action that would modify the collection of this smart contract libraries by adding or removing library with code given in Cell c. If x=0, the library is actually removed if it was previously present in the collection (if not, this action does nothing). If x=1, the library is added as a private library, and if x=2, the library is added as a public library (and becomes available to all smart contracts if the current smart contract resides in the masterchain); if the library was present in the collection before, its public/private status is changed according to x. Values of x other than 0...2 are invalid.	526
FB07	CHANGELIB	h x -	Creates an output action similarly to SETLIBCODE, but instead of the library code accepts its hash as an unsigned 256-bit integer h. If x!=0 and the library with hash h is absent from the library collection of this smart contract, this output action will fail.	526

12 Debug primitives

Opcodes beginning with FE are reserved for the debug primitives. These primitives have known fixed operation length and behave as (multibyte) NOP operations.

However, when invoked in a TVM instance with debug mode enabled, these primitives can produce a specific output into the text debug log of the TVM instance, never affecting the TVM state.

DEBUG and DEBUGSTR are the two debug primitives, they cover all opcodes that start with FE. Other primitives listed here have opcodes from the same set. When debug is enabled, they have their specified effects. When debug is disabled, they behave as NOP.

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
FEnn	{nn} DEBUG	-	0 <= nn < 240	26
FEFnssss	{string} DEBUGSTR {string} {x} DEBUGSTRI	-	0 <= n < 16. Length of ssss is n+1 bytes. {string} is a string literal. DEBUGSTR: ssss is the given string. DEBUGSTRI: ssss is one-byte integer 0 <= x <= 255 followed by the given string.	26
FE00	DUMPSTK	-	Dumps the stack (at most the top 255 values) and shows the total stack depth.	26
FE2i	s[i] DUMP	-	Dumps s[i].	26

13 Codepage primitives

xxxxxxx Opcode	xxxxxxxxxxxxxxxxxxxxxxxxxxxx Fift syntax	xxxxxxxxxxxxxxxxx Stack	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Description	xxxx Gas
FFnn	[nn] SETCP	-	Selects TVM codepage 0 <= nn < 240. If the codepage is not supported, throws an invalid opcode exception.	26
FF00	SETCP0	-	Selects TVM (test) codepage zero as described in this document.	26
FFFz	[z-16] SETCP	-	Selects TVM codepage z-16 for 1 <= z <= 15. Negative codepages -13...-1 are reserved for restricted versions of TVM needed to validate runs of TVM in other codepages. Negative codepage -14 is reserved for experimental codepages, not necessarily compatible between different TVM implementations, and should be disabled in the production versions of TVM.	26
FFF0	SETCPX	c -	Selects codepage c with -2^15 <= c < 2^15 passed in the top of the stack.	26