Skip to main content

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.

info

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.
info

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

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

OpcodeFift syntaxStackGasDescription
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
00NOP-Does nothing.18
01SWAPx y - y xSame as s1 XCHG0.18
0is[i] XCHG0Interchanges s0 with s[i], 1 <= i <= 15.18
10ijs[i] s[j] XCHGInterchanges s[i] with s[j], 1 <= i < j <= 15.26
11iis0 [ii] s() XCHGInterchanges s0 with s[ii], 0 <= ii <= 255.26
1is1 s[i] XCHGInterchanges s1 with s[i], 2 <= i <= 15.18
2is[i] PUSHPushes a copy of the old s[i] into the stack.18
20DUPx - x xSame as s0 PUSH.18
21OVERx y - x y xSame as s1 PUSH.18
3is[i] POPPops the old s0 value into the old s[i]. Equivalent to s[i] XCHG0 DROP18
30DROPx -Same as s0 POP, discards the top-of-stack value.18
31NIPx y - ySame as s1 POP.18

2.2 Complex stack manipulation primitives

xxxxxxx
Opcode
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fift syntax
xxxxxxxxxxxxxxxxx
Stack
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Description
xxxx
Gas
4ijks[i] s[j] s[k] XCHG3Equivalent to s2 s[i] XCHG s1 s[j] XCHG s[k] XCHG0.26
50ijs[i] s[j] XCHG2Equivalent to s1 s[i] XCHG s[j] XCHG0.26
51ijs[i] s[j] XCPUEquivalent to s[i] XCHG0 s[j] PUSH.26
52ijs[i] s[j-1] PUXCEquivalent to s[i] PUSH SWAP s[j] XCHG0.26
53ijs[i] s[j] PUSH2Equivalent to s[i] PUSH s[j+1] PUSH.26
540ijks[i] s[j] s[k] XCHG3_lLong form of XCHG3.34
541ijks[i] s[j] s[k] XC2PUEquivalent to s[i] s[j] XCHG2 s[k] PUSH.34
542ijks[i] s[j] s[k-1] XCPUXCEquivalent to s1 s[i] XCHG s[j] s[k-1] PUXC.34
543ijks[i] s[j] s[k] XCPU2Equivalent to s[i] XCHG0 s[j] s[k] PUSH2.34
544ijks[i] s[j-1] s[k-1] PUXC2Equivalent to s[i] PUSH s2 XCHG0 s[j] s[k] XCHG2.34
545ijks[i] s[j-1] s[k-1] PUXCPUEquivalent to s[i] s[j-1] PUXC s[k] PUSH.34
546ijks[i] s[j-1] s[k-2] PU2XCEquivalent to s[i] PUSH SWAP s[j] s[k-1] PUXC.34
547ijks[i] s[j] s[k] PUSH3Equivalent to s[i] PUSH s[j+1] s[k+1] PUSH2.34
55ij[i+1] [j+1] BLKSWAPPermutes 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
5513ROT2
2ROT
a b c d e f - c d e f a bRotates the three topmost pairs of stack entries.26
550i[i+1] ROLLRotates 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() PUSHPushes a copy of the old s[ii] into the stack.
0 <= ii <= 255
26
57ii[ii] s() POPPops the old s0 value into the old s[ii].
0 <= ii <= 255
26
58ROTa b c - b c aEquivalent to 1 2 BLKSWAP or to s2 s1 XCHG2.18
59ROTREV
-ROT
a b c - c a bEquivalent to 2 1 BLKSWAP or to s2 s2 XCHG2.18
5ASWAP2
2SWAP
a b c d - c d a bEquivalent to 2 2 BLKSWAP or to s3 s2 XCHG2.18
5BDROP2
2DROP
a b - Equivalent to DROP DROP.18
5CDUP2
2DUP
a b - a b a bEquivalent to s1 s0 PUSH2.18
5DOVER2
2OVER
a b c d - a b c d a bEquivalent to s3 s2 PUSH2.18
5Eij[i+2] [j] REVERSEReverses the order of s[j+i+1] … s[j].26
5F0i[i] BLKDROPEquivalent to DROP performed i times.26
5Fij[i] [j] BLKPUSHEquivalent to PUSH s(j) performed i times.
1 <= i <= 15, 0 <= j <= 15.
26
60PICK
PUSHX
Pops integer i from the stack, then performs s[i] PUSH.18
61ROLLXPops 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
63BLKSWXPops integers i,j from the stack, then performs [i] [j] BLKSWAP.18
64REVXPops integers i,j from the stack, then performs [i] [j] REVERSE.18
65DROPXPops integer i from the stack, then performs [i] BLKDROP.18
66TUCKa b - b a bEquivalent to SWAP OVER or to s1 s1 XCPU.18
67XCHGXPops integer i from the stack, then performs s[i] XCHG.18
68DEPTH- depthPushes the current depth of the stack.18
69CHKDEPTHi -Pops integer i from the stack, then checks whether there are at least i elements, generating a stack underflow exception otherwise.18/58
6AONLYTOPXPops integer i from the stack, then removes all but the top i elements.18
6BONLYXPops integer i from the stack, then leaves only the bottom i elements. Approximately equivalent to DEPTH SWAP SUB DROPX.18
6Cij[i] [j] BLKDROP2Drops 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
6DNULL
PUSHNULL
- nullPushes the only value of type Null.18
6EISNULLx - ?Checks whether x is a Null, and returns -1 or 0 accordingly.18
6F0n[n] TUPLEx_1 ... x_n - tCreates a new Tuple t=(x_1, … ,x_n) containing n values x_1,..., x_n.
0 <= n <= 15
26+n
6F00NIL- tPushes the only Tuple t=() of length zero.26
6F01SINGLEx - tCreates a singletos t:=(x), i.e., a Tuple of length one.27
6F02PAIR
CONS
x y - tCreates pair t:=(x,y).28
6F03TRIPLEx y z - tCreates triple t:=(x,y,z).29
6F1k[k] INDEXt - xReturns the k-th element of a Tuple t.
0 <= k <= 15.
26
6F10FIRST
CAR
t - xReturns the first element of a Tuple.26
6F11SECOND
CDR
t - yReturns the second element of a Tuple.26
6F12THIRDt - zReturns the third element of a Tuple.26
6F2n[n] UNTUPLEt - x_1 ... x_nUnpacks 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
6F21UNSINGLEt - xUnpacks a singletos t=(x).27
6F22UNPAIR
UNCONS
t - x yUnpacks a pair t=(x,y).28
6F23UNTRIPLEt - x y zUnpacks a triple t=(x,y,z).29
6F3k[k] UNPACKFIRSTt - x_1 ... x_kUnpacks first 0 <= k <= 15 elements of a Tuple t.
If \|t\|<k, throws a type check exception.
26+k
6F30CHKTUPLEt -Checks whether t is a Tuple. If not, throws a type check exception.26
6F4n[n] EXPLODEt - x_1 ... x_m mUnpacks 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] SETINDEXt 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\|
6F50SETFIRSTt x - t'Sets the first component of Tuple t to x and returns the resulting Tuple t'.26+\|t\|
6F51SETSECONDt x - t'Sets the second component of Tuple t to x and returns the resulting Tuple t'.26+\|t\|
6F52SETTHIRDt x - t'Sets the third component of Tuple t to x and returns the resulting Tuple t'.26+\|t\|
6F6k[k] INDEXQt - xReturns 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
6F60FIRSTQ
CARQ
t - xReturns the first element of a Tuple.26
6F61SECONDQ
CDRQ
t - yReturns the second element of a Tuple.26
6F62THIRDQt - zReturns the third element of a Tuple.26
6F7k[k] SETINDEXQt 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’\|
6F70SETFIRSTQt x - t'Sets the first component of Tuple t to x and returns the resulting Tuple t'.26+\|t’\|
6F71SETSECONDQt x - t'Sets the second component of Tuple t to x and returns the resulting Tuple t'.26+\|t’\|
6F72SETTHIRDQt x - t'Sets the third component of Tuple t to x and returns the resulting Tuple t'.26+\|t’\|
6F80TUPLEVARx_1 ... x_n n - tCreates a new Tuple t of length n similarly to TUPLE, but with 0 <= n <= 255 taken from the stack.26+n
6F81INDEXVARt k - xSimilar to k INDEX, but with 0 <= k <= 254 taken from the stack.26
6F82UNTUPLEVARt n - x_1 ... x_nSimilar to n UNTUPLE, but with 0 <= n <= 255 taken from the stack.26+n
6F83UNPACKFIRSTVARt n - x_1 ... x_nSimilar to n UNPACKFIRST, but with 0 <= n <= 255 taken from the stack.26+n
6F84EXPLODEVARt n - x_1 ... x_m mSimilar to n EXPLODE, but with 0 <= n <= 255 taken from the stack.26+m
6F85SETINDEXVARt x k - t'Similar to k SETINDEX, but with 0 <= k <= 254 taken from the stack.26+\|t’\|
6F86INDEXVARQt k - xSimilar to n INDEXQ, but with 0 <= k <= 254 taken from the stack.26
6F87SETINDEXVARQt x k - t'Similar to k SETINDEXQ, but with 0 <= k <= 254 taken from the stack.26+\|t’\|
6F88TLENt - nReturns the length of a Tuple.26
6F89QTLENt - n or -1Similar to TLEN, but returns -1 if t is not a Tuple.26
6F8AISTUPLEt - ?Returns -1 or 0 depending on whether t is a Tuple.26
6F8BLASTt - xReturns the last element of a non-empty Tuple t.26
6F8CTPUSH
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’\|
6F8DTPOPt - t' xDetaches 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’\|
6FA0NULLSWAPIFx - x or null xPushes a Null under the topmost Integer x, but only if x!=0.26
6FA1NULLSWAPIFNOTx - x or null xPushes 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
6FA2NULLROTRIFx y - x y or null x yPushes a Null under the second stack entry from the top, but only if the topmost Integer y is non-zero.26
6FA3NULLROTRIFNOTx y - x y or null x yPushes 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
6FA4NULLSWAPIF2x - x or null null xPushes two nulls under the topmost Integer x, but only if x!=0.
Equivalent to NULLSWAPIF NULLSWAPIF.
26
6FA5NULLSWAPIFNOT2x - x or null null xPushes two nulls under the topmost Integer x, but only if x=0.
Equivalent to NULLSWAPIFNOT NULLSWAPIFNOT.
26
6FA6NULLROTRIF2x y - x y or null null x yPushes 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
6FA7NULLROTRIFNOT2x y - x y or null null x yPushes 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] INDEX2t - xRecovers x=(t_{i+1})_{j+1} for 0 <= i,j <= 3.
Equivalent to [i] INDEX [j] INDEX.
26
6FB4CADRt - xRecovers x=(t_2)_1.26
6FB5CDDRt - xRecovers x=(t_2)_2.26
6FE_ijk[i] [j] [k] INDEX3t - xRecovers x=t_{i+1}_{j+1}_{k+1}.
0 <= i,j,k <= 3
Equivalent to [i] [j] INDEX2 [k] INDEX.
26
6FD4CADDRt - xRecovers x=t_2_2_1.26
6FD5CDDDRt - xRecovers 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
- xPushes integer x into the stack. -5 <= x <= 10.
Here i equals four lower-order bits of x (i=x mod 16).
18
70ZERO
FALSE
- 018
71ONE- 118
72TWO- 218
7ATEN- 1018
7FTRUE- -118
80xx[xx] PUSHINT
[xx] INT
- xxPushes integer xx. -128 <= xx <= 127.26
81xxxx[xxxx] PUSHINT
[xxxx] INT
- xxxxPushes integer xxxx. -2^15 <= xx < 2^15.34
82lxxx[xxx] PUSHINT
[xxx] INT
- xxxPushes 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
83FFPUSHNAN- NaNPushes a NaN.26
84xx[xx+1] PUSHPOW2DEC- 2^(xx+1)-1Pushes 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- cPushes 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- sSimilar to PUSHREF, but converts the cell into a Slice.118/43
8A[ref] PUSHREFCONT- contSimilar to PUSHREFSLICE, but makes a simple ordinary Continuation out of the cell.118/43
8Bxsss[slice] PUSHSLICE
[slice] SLICE
- sPushes 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
- sPushes 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
- sPushes 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
- sExamples 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/sExamples of PUSHREF and PUSHREFSLICE.
More on building cells in fift here.
8F_rxxcccc[builder] PUSHCONT
[builder] CONT
- cPushes 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
- cPushes a continuation made from builder.
Details: Pushes an x-byte continuation for 0 <= x <= 15.
18
<{ code }> PUSHCONT
<{ code }> CONT
CONT:<{ code }>
- cPushes 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
A0ADDx y - x+y18
A1SUBx y - x-y18
A2SUBRx y - y-xEquivalent to SWAP SUB.18
A3NEGATEx - -xEquivalent to -1 MULCONST or to ZERO SUBR.
Notice that it triggers an integer overflow exception if x=-2^256.
18
A4INCx - x+1Equivalent to 1 ADDCONST.18
A5DECx - x-1Equivalent 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
A8MULx y - x*y18

5.2 Division

xxxxxxx
Opcode
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fift syntax
xxxxxxxxxxxxxxxxx
Stack
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Description
xxxx
Gas
A9mscdfThis 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
A904DIVx y - qq=floor(x/y), r=x-y*q26
A905DIVRx y - q’q’=round(x/y), r’=x-y*q’26
A906DIVCx y - q''q’’=ceil(x/y), r’’=x-y*q’’26
A908MODx y - r26
A90CDIVMODx y - q r26
A90DDIVMODRx y - q' r'26
A90EDIVMODCx y - q'' r''26
A925RSHIFTRx y - round(x/2^y)26
A926RSHIFTCx 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
A98MULDIVx y z - qq=floor(x*y/z)26
A985MULDIVRx y z - q'q'=round(x*y/z)26
A98CMULDIVMODx y z - q rq=floor(x*y/z), r=x*y-z*q26
A9A4MULRSHIFTx y z - floor(x*y/2^z)0 <= z <= 25626
A9A5MULRSHIFTRx y z - round(x*y/2^z)0 <= z <= 25626
A9A6MULRSHIFTCx y z - ceil(x*y/2^z)0 <= z <= 25634
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
A9C4LSHIFTDIVx y z - floor(2^z*x/y)0 <= z <= 25626
A9C5LSHIFTDIVRx y z - round(2^z*x/y)0 <= z <= 25626
A9C6LSHIFTDIVCx y z - ceil(2^z*x/y)0 <= z <= 25634
A9D4tt[tt+1] LSHIFT#DIVx y - floor(2^(tt+1)*x/y)34
A9D5tt[tt+1] LSHIFT#DIVRx y - round(2^(tt+1)*x/y)34
A9D6tt[tt+1] LSHIFT#DIVCx 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 <= 25526
ABcc[cc+1] RSHIFT#x - floor(x/2^(cc+1))0 <= cc <= 25518
ACLSHIFTx y - x*2^y0 <= y <= 102318
ADRSHIFTx y - floor(x/2^y)0 <= y <= 102318
AEPOW2y - 2^y0 <= y <= 1023
Equivalent to ONE SWAP LSHIFT.
18
B0ANDx y - x&yBitwise and of two signed integers x and y, sign-extended to infinity.18
B1ORx y - x\|yBitwise or of two integers.18
B2XORx y - x xor yBitwise xor of two integers.18
B3NOTx - ~xBitwise not of an integer.26
B4cc[cc+1] FITSx - xChecks 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
B400CHKBOOLx - xChecks whether x is a “boolean value'' (i.e., either 0 or -1).26/76
B5cc[cc+1] UFITSx - xChecks whether x is a cc+1-bit unsigned integer for 0 <= cc <= 255 (i.e., whether 0 <= x < 2^(cc+1)).26/76
B500CHKBITx - xChecks whether x is a binary digit (i.e., zero or one).26/76
B600FITSXx c - xChecks whether x is a c-bit signed integer for 0 <= c <= 1023.26/76
B601UFITSXx c - xChecks whether x is a c-bit unsigned integer for 0 <= c <= 1023.26/76
B602BITSIZEx - cComputes smallest c >= 0 such that x fits into a c-bit signed integer (-2^(c-1) <= c < 2^(c-1)).26
B603UBITSIZEx - cComputes smallest c >= 0 such that x fits into a c-bit unsigned integer (0 <= x < 2^c), or throws a range check exception.26
B608MINx y - x or yComputes the minimum of two integers x and y.26
B609MAXx y - x or yComputes the maximum of two integers x and y.26
B60AMINMAX
INTSORT2
x y - x y or y xSorts two integers. Quiet version of this operation returns two NaNs if any of the arguments are NaNs.26
B60BABSx - \|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
B7A0QADDx y - x+y26
B7A1QSUBx y - x-y26
B7A2QSUBRx y - y-x26
B7A3QNEGATEx - -x26
B7A4QINCx - x+126
B7A5QDECx - x-126
B7A8QMULx y - x*y26
B7A904QDIVx y - qDivision returns NaN if y=0.34
B7A905QDIVRx y - q’34
B7A906QDIVCx y - q''34
B7A908QMODx y - r34
B7A90CQDIVMODx y - q r34
B7A90DQDIVMODRx y - q' r'34
B7A90EQDIVMODCx y - q'' r''34
B7A985QMULDIVRx y z - q'34
B7A98CQMULDIVMODx y z - q r34
B7ACQLSHIFTx y - x*2^y26
B7ADQRSHIFTx y - floor(x/2^y)26
B7AEQPOW2y - 2^y26
B7B0QANDx y - x&y26
B7B1QORx y - x\|y26
B7B2QXORx y - x xor y26
B7B3QNOTx - ~x26
B7B4cc[cc+1] QFITSx - xReplaces x with a NaN if x is not a cc+1-bit signed integer, leaves it intact otherwise.34
B7B5cc[cc+1] QUFITSx - xReplaces x with a NaN if x is not a cc+1-bit unsigned integer, leaves it intact otherwise.34
B7B600QFITSXx c - xReplaces x with a NaN if x is not a c-bit signed integer, leaves it intact otherwise.34
B7B601QUFITSXx c - xReplaces 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
B8SGNx - sgn(x)Computes the sign of an integer x:
-1 if x<0, 0 if x=0, 1 if x>0.
18
B9LESSx y - x<yReturns -1 if x<y, 0 otherwise.18
BAEQUALx y - x=yReturns -1 if x=y, 0 otherwise.18
BBLEQx y - x<=y18
BCGREATERx y - x>y18
BDNEQx y - x!=yEquivalent to EQUAL NOT.18
BEGEQx y - x>=yEquivalent to LESS NOT.18
BFCMPx 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] EQINTx - x=yyReturns -1 if x=yy, 0 otherwise.
-2^7 <= yy < 2^7.
26
C000ISZEROx - x=0Checks whether an integer is zero. Corresponds to Forth's 0=.26
C1yy[yy] LESSINT
[yy-1] LEQINT
x - x<yyReturns -1 if x<yy, 0 otherwise.
-2^7 <= yy < 2^7.
26
C100ISNEGx - x<0Checks whether an integer is negative. Corresponds to Forth's 0<.26
C101ISNPOSx - x<=0Checks whether an integer is non-positive.26
C2yy[yy] GTINT
[yy+1] GEQINT
x - x>yyReturns -1 if x>yy, 0 otherwise.
-2^7 <= yy < 2^7.
26
C200ISPOSx - x>0Checks whether an integer is positive. Corresponds to Forth's 0>.26
C2FFISNNEGx - x >=0Checks whether an integer is non-negative.26
C3yy[yy] NEQINTx - x!=yyReturns -1 if x!=yy, 0 otherwise.
-2^7 <= yy < 2^7.
26
C4ISNANx - x=NaNChecks whether x is a NaN.18
C5CHKNANx - xThrows 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
C700SEMPTYs - ?Checks whether a Slice s is empty (i.e., contains no bits of data and no cell references).26
C701SDEMPTYs - ?Checks whether Slice s has no bits of data.26
C702SREMPTYs - ?Checks whether Slice s has no references.26
C703SDFIRSTs - ?Checks whether the first bit of Slice s is a one.26
C704SDLEXCMPs s' - xCompares the data of s lexicographically with the data of s', returning -1, 0, or 1 depending on the result.26
C705SDEQs s' - ?Checks whether the data parts of s and s' coincide, equivalent to SDLEXCMP ISZERO.26
C708SDPFXs s' - ?Checks whether s is a prefix of s'.26
C709SDPFXREVs s' - ?Checks whether s' is a prefix of s, equivalent to SWAP SDPFX.26
C70ASDPPFXs s' - ?Checks whether s is a proper prefix of s' (i.e., a prefix distinct from s').26
C70BSDPPFXREVs s' - ?Checks whether s' is a proper prefix of s.26
C70CSDSFXs s' - ?Checks whether s is a suffix of s'.26
C70DSDSFXREVs s' - ?Checks whether s' is a suffix of s.26
C70ESDPSFXs s' - ?Checks whether s is a proper suffix of s'.26
C70FSDPSFXREVs s' - ?Checks whether s' is a proper suffix of s.26
C710SDCNTLEAD0s - nReturns the number of leading zeroes in s.26
C711SDCNTLEAD1s - nReturns the number of leading ones in s.26
C712SDCNTTRAIL0s - nReturns the number of trailing zeroes in s.26
C713SDCNTTRAIL1s - nReturns 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
C8NEWC- bCreates a new empty Builder.18
C9ENDCb - cConverts a Builder into an ordinary Cell.518
CAcc[cc+1] STIx 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] STUx b - b'Stores an unsigned cc+1-bit integer x into Builder b. In all other respects it is similar to STI.26
CCSTREFc b - b'Stores a reference to Cell c into Builder b.18
CDSTBREFR
ENDCST
b b'' - bEquivalent to ENDC SWAP STREF.518
CESTSLICEs b - b'Stores Slice s into Builder b.18
CF00STIXx b l - b'Stores a signed l-bit integer x into b for 0 <= l <= 257.26
CF01STUXx b l - b'Stores an unsigned l-bit integer x into b for 0 <= l <= 256.26
CF02STIXRb x l - b'Similar to STIX, but with arguments in a different order.26
CF03STUXRb x l - b'Similar to STUX, but with arguments in a different order.26
CF04STIXQx b l - x b f or b' 0A 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
CF05STUXQx b l - x b f or b' 0A quiet version of STUX.26
CF06STIXRQb x l - b x f or b' 0A quiet version of STIXR.26
CF07STUXRQb x l - b x f or b' 0A quiet version of STUXR.26
CF08cc[cc+1] STI_lx b - b'A longer version of [cc+1] STI.34
CF09cc[cc+1] STU_lx b - b'A longer version of [cc+1] STU.34
CF0Acc[cc+1] STIRb x - b'Equivalent to SWAP [cc+1] STI.34
CF0Bcc[cc+1] STURb x - b'Equivalent to SWAP [cc+1] STU.34
CF0Ccc[cc+1] STIQx b - x b f or b' 0A quiet version of STI.34
CF0Dcc[cc+1] STUQx b - x b f or b' 0A quiet version of STU.34
CF0Ecc[cc+1] STIRQb x - b x f or b' 0A quiet version of STIR.34
CF0Fcc[cc+1] STURQb x - b x f or b' 0A quiet version of STUR.34
CF10STREF_lc b - b'A longer version of STREF.26
CF11STBREFb' b - b''Equivalent to SWAP STBREFR.526
CF12STSLICE_ls b - b'A longer version of STSLICE.26
CF13STBb' b - b''Appends all data from Builder b' to Builder b.26
CF14STREFRb c - b'Equivalent to SWAP STREF.26
CF15STBREFR_lb b' - b''A longer encoding of STBREFR.526
CF16STSLICERb s - b'Equivalent to SWAP STSLICE.26
CF17STBR
BCONCAT
b b' - b''Concatenates two builders.
Equivalent to SWAP STB.
26
CF18STREFQc b - c b -1 or b' 0Quiet version of STREF.26
CF19STBREFQb' b - b' b -1 or b'' 0Quiet version of STBREF.526
CF1ASTSLICEQs b - s b -1 or b' 0Quiet version of STSLICE.26
CF1BSTBQb' b - b' b -1 or b'' 0Quiet version of STB.26
CF1CSTREFRQb c - b c -1 or b' 0Quiet version of STREFR.26
CF1DSTBREFRQb b' - b b' -1 or b'' 0Quiet version of STBREFR.526
CF1ESTSLICERQb s - b s -1 or b'' 0Quiet version of STSLICER.26
CF1FSTBRQ
BCONCATQ
b b' - b b' -1 or b'' 0Quiet version of STBR.26
CF20[ref] STREFCONSTb - b’Equivalent to PUSHREF STREFR.26
CF21[ref] [ref] STREF2CONSTb - b’Equivalent to STREFCONST STREFCONST.26
CF23b x - cIf 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
CF28STILE4x b - b'Stores a little-endian signed 32-bit integer.26
CF29STULE4x b - b'Stores a little-endian unsigned 32-bit integer.26
CF2ASTILE8x b - b'Stores a little-endian signed 64-bit integer.26
CF2BSTULE8x b - b'Stores a little-endian unsigned 64-bit integer.26
CF30BDEPTHb - xReturns 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
CF31BBITSb - xReturns the number of data bits already stored in Builder b.26
CF32BREFSb - yReturns the number of cell references already stored in b.26
CF33BBITREFSb - x yReturns the numbers of both data bits and cell references in b.26
CF35BREMBITSb - x'Returns the number of data bits that can still be stored in b.26
CF36BREMREFSb - y'Returns the number of references that can still be stored in b.26
CF37BREMBITREFSb - 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
CF39BCHKBITSb 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
CF3ABCHKREFSb y - Checks whether y references can be stored into b, 0 <= y <= 7.26/76
CF3BBCHKBITREFSb 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
CF3DBCHKBITSQb x - ?Checks whether x bits can be stored into b, 0 <= x <= 1023.26
CF3EBCHKREFSQb y - ?Checks whether y references can be stored into b, 0 <= y <= 7.26
CF3FBCHKBITREFSQb x y - ?Checks whether x bits and y references can be stored into b, 0 <= x <= 1023, 0 <= y <= 7.26
CF40STZEROESb n - b'Stores n binary zeroes into Builder b.26
CF41STOSESb n - b'Stores n binary ones into Builder b.26
CF42STSAMEb n x - b'Stores n binary xes (0 <= x <= 1) into Builder b.26
CFC0_xysss[slice] STSLICECONSTb - 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
CF81STZEROb - b'Stores one binary zero.24
CF83STOSEb - b'Stores one binary one.24

7.2 Cell deserialization primitives

xxxxxxx
Opcode
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fift syntax
xxxxxxxxxxxxxxxxx
Stack
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Description
xxxx
Gas
D0CTOSc - sConverts 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
D1ENDSs - Removes a Slice s from the stack, and throws an exception if it is not empty.18/68
D2cc[cc+1] LDIs - 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] LDUs - x s'Loads an unsigned cc+1-bit integer x from Slice s.26
D4LDREFs - c s'Loads a cell reference c from s.18
D5LDREFRTOSs - s' s''Equivalent to LDREF SWAP CTOS.118/43
D6cc[cc+1] LDSLICEs - s'' s'Cuts the next cc+1 bits of s into a separate Slice s''.26
D700LDIXs 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
D701LDUXs l - x s'Loads an unsigned l-bit integer x from (the first l bits of) s, with 0 <= l <= 256.26
D702PLDIXs l - xPreloads a signed l-bit integer from Slice s, for 0 <= l <= 257.26
D703PLDUXs l - xPreloads an unsigned l-bit integer from s, for 0 <= l <= 256.26
D704LDIXQs l - x s' -1 or s 0Quiet 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
D705LDUXQs l - x s' -1 or s 0Quiet version of LDUX.26
D706PLDIXQs l - x -1 or 0Quiet version of PLDIX.26
D707PLDUXQs l - x -1 or 0Quiet version of PLDUX.26
D708cc[cc+1] LDI_ls - x s'A longer encoding for LDI.34
D709cc[cc+1] LDU_ls - x s'A longer encoding for LDU.34
D70Acc[cc+1] PLDIs - xPreloads a signed cc+1-bit integer from Slice s.34
D70Bcc[cc+1] PLDUs - xPreloads an unsigned cc+1-bit integer from s.34
D70Ccc[cc+1] LDIQs - x s' -1 or s 0A quiet version of LDI.34
D70Dcc[cc+1] LDUQs - x s' -1 or s 0A quiet version of LDU.34
D70Ecc[cc+1] PLDIQs - x -1 or 0A quiet version of PLDI.34
D70Fcc[cc+1] PLDUQs - x -1 or 0A quiet version of PLDU.34
D714_c[32(c+1)] PLDUZs - s xPreloads 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
D718LDSLICEXs 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
D719PLDSLICEXs l - s''Returns the first 0 <= l <= 1023 bits of s as s''.26
D71ALDSLICEXQs l - s'' s' -1 or s 0A quiet version of LDSLICEX.26
D71BPLDSLICEXQs l - s' -1 or 0A quiet version of LDSLICEXQ.26
D71Ccc[cc+1] LDSLICE_ls - s'' s'A longer encoding for LDSLICE.34
D71Dcc[cc+1] PLDSLICEs - s''Returns the first 0 < cc+1 <= 256 bits of s as s''.34
D71Ecc[cc+1] LDSLICEQs - s'' s' -1 or s 0A quiet version of LDSLICE.34
D71Fcc[cc+1] PLDSLICEQs - s'' -1 or 0A quiet version of PLDSLICE.34
D720SDCUTFIRSTs l - s'Returns the first 0 <= l <= 1023 bits of s. It is equivalent to PLDSLICEX.26
D721SDSKIPFIRSTs l - s'Returns all but the first 0 <= l <= 1023 bits of s. It is equivalent to LDSLICEX NIP.26
D722SDCUTLASTs l - s'Returns the last 0 <= l <= 1023 bits of s.26
D723SDSKIPLASTs l - s'Returns all but the last 0 <= l <= 1023 bits of s.26
D724SDSUBSTRs 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
D726SDBEGINSXs 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
D727SDBEGINSXQs s' - s'' -1 or s 0A quiet version of SDBEGINSX.26
D72A_xsss[slice] SDBEGINSs - 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] SDBEGINSQs - s'' -1 or s 0A quiet version of SDBEGINS.31
D730SCUTFIRSTs l r - s'Returns the first 0 <= l <= 1023 bits and first 0 <= r <= 4 references of s.26
D731SSKIPFIRSTs l r - s'Returns all but the first l bits of s and r references of s.26
D732SCUTLASTs l r - s'Returns the last 0 <= l <= 1023 data bits and last 0 <= r <= 4 references of s.26
D733SSKIPLASTs l r - s'Returns all but the last l bits of s and r references of s.26
D734SUBSLICEs 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
D736SPLITs 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
D737SPLITQs l r - s' s'' -1 or s 0A quiet version of SPLIT.26
D739c - 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.
D73Ac - 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.
D73Bc - c' -1 or c 0Loads an exotic cell c and returns an ordinary cell c'. If c is already ordinary, does nothing. If c cannot be loaded, returns 0.
D741SCHKBITSs 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
D742SCHKREFSs r - Checks whether there are at least r references in Slice s.26/76
D743SCHKBITREFSs l r - Checks whether there are at least l data bits and r references in Slice s.26/76
D745SCHKBITSQs l - ?Checks whether there are at least l data bits in Slice s.26
D746SCHKREFSQs r - ?Checks whether there are at least r references in Slice s.26
D747SCHKBITREFSQs l r - ?Checks whether there are at least l data bits and r references in Slice s.26
D748PLDREFVARs n - cReturns the n-th cell reference of Slice s for 0 <= n <= 3.26
D749SBITSs - lReturns the number of data bits in Slice s.26
D74ASREFSs - rReturns the number of references in Slice s.26
D74BSBITREFSs - l rReturns both the number of data bits and the number of references in s.26
D74E_n[n] PLDREFIDXs - cReturns the n-th cell reference of Slice s, where 0 <= n <= 3.26
D74CPLDREFs - cPreloads the first cell reference of a Slice.26
D750LDILE4s - x s'Loads a little-endian signed 32-bit integer.26
D751LDULE4s - x s'Loads a little-endian unsigned 32-bit integer.26
D752LDILE8s - x s'Loads a little-endian signed 64-bit integer.26
D753LDULE8s - x s'Loads a little-endian unsigned 64-bit integer.26
D754PLDILE4s - xPreloads a little-endian signed 32-bit integer.26
D755PLDULE4s - xPreloads a little-endian unsigned 32-bit integer.26
D756PLDILE8s - xPreloads a little-endian signed 64-bit integer.26
D757PLDULE8s - xPreloads a little-endian unsigned 64-bit integer.26
D758LDILE4Qs - x s' -1 or s 0Quietly loads a little-endian signed 32-bit integer.26
D759LDULE4Qs - x s' -1 or s 0Quietly loads a little-endian unsigned 32-bit integer.26
D75ALDILE8Qs - x s' -1 or s 0Quietly loads a little-endian signed 64-bit integer.26
D75BLDULE8Qs - x s' -1 or s 0Quietly loads a little-endian unsigned 64-bit integer.26
D75CPLDILE4Qs - x -1 or 0Quietly preloads a little-endian signed 32-bit integer.26
D75DPLDULE4Qs - x -1 or 0Quietly preloads a little-endian unsigned 32-bit integer.26
D75EPLDILE8Qs - x -1 or 0Quietly preloads a little-endian signed 64-bit integer.26
D75FPLDULE8Qs - x -1 or 0Quietly preloads a little-endian unsigned 64-bit integer.26
D760LDZEROESs - n s'Returns the count n of leading zero bits in s, and removes these bits from s.26
D761LDONESs - n s'Returns the count n of leading one bits in s, and removes these bits from s.26
D762LDSAMEs x - n s'Returns the count n of leading bits equal to 0 <= x <= 1 in s, and removes these bits from s.26
D764SDEPTHs - xReturns 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
D765CDEPTHc - xReturns 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
D8EXECUTE
CALLX
c - Calls, or executes, continuation c.18
D9JMPXc - Jumps, or transfers control, to continuation c.
The remainder of the previous current continuation cc is discarded.
18
DApr[p] [r] CALLXARGSc - Calls continuation c with p parameters and expecting r return values
0 <= p <= 15, 0 <= r <= 15
26
DB0p[p] -1 CALLXARGSc - Calls continuation c with 0 <= p <= 15 parameters, expecting an arbitrary number of return values.26
DB1p[p] JMPXARGSc - 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] RETARGSReturns to c0, with 0 <= r <= 15 return values taken from the current stack.26
DB30RET
RETTRUE
Returns to the continuation at c0. The remainder of the current continuation cc is discarded.
Approximately equivalent to c0 PUSHCTR JMPX.
26
DB31RETALT
RETFALSE
Returns to the continuation at c1.
Approximately equivalent to c1 PUSHCTR JMPX.
26
DB32BRANCH
RETBOOL
f - Performs RETTRUE if integer f!=0, or RETFALSE if f=0.26
DB34CALLCCc - 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
DB35JMPXDATAc - 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] CALLCCARGSc - 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
DB38CALLXVARARGSc 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
DB39RETVARARGSp r - Similar to RETARGS.26
DB3AJMPXVARARGSc p r - Similar to JMPXARGS.26
DB3BCALLCCVARARGSc p r - Similar to CALLCCARGS.26
DB3C[ref] CALLREFEquivalent to PUSHREFCONT CALLX.126/51
DB3D[ref] JMPREFEquivalent to PUSHREFCONT JMPX.126/51
DB3E[ref] JMPREFDATAEquivalent to PUSHREFCONT JMPXDATA.126/51
DB3FRETDATAEquivalent 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
DCIFRET
IFNOT:
f - Performs a RET, but only if integer f is non-zero. If f is a NaN, throws an integer overflow exception.18
DDIFNOTRET
IF:
f - Performs a RET, but only if integer f is zero.18
DEIFf c - Performs EXECUTE for c (i.e., executes c), but only if integer f is non-zero. Otherwise simply discards both values.18
DEIF:<{ code }>
<{ code }>IF
f -Equivalent to <{ code }> CONT IF.
DFIFNOTf c - Executes continuation c, but only if integer f is zero. Otherwise simply discards both values.18
DFIFNOT:<{ code }>
<{ code }>IFNOT
f -Equivalent to <{ code }> CONT IFNOT.
E0IFJMPf c - Jumps to c (similarly to JMPX), but only if f is non-zero.18
E0IFJMP:<{ code }>f -Equivalent to <{ code }> CONT IFJMP.
E1IFNOTJMPf c - Jumps to c (similarly to JMPX), but only if f is zero.18
E1IFNOTJMP:<{ code }>f -Equivalent to <{ code }> CONT IFNOTJMP.
E2IFELSEf c c' - If integer f is non-zero, executes c, otherwise executes c'. Equivalent to CONDSELCHK EXECUTE.18
E2IF:<{ code1 }>ELSE<{ code2 }>f -Equivalent to <{ code1 }> CONT <{ code2 }> CONT IFELSE.
E300[ref] IFREFf - 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] IFNOTREFf - Equivalent to PUSHREFCONT IFNOT.26/126/51
E302[ref] IFJMPREFf - Equivalent to PUSHREFCONT IFJMP.26/126/51
E303[ref] IFNOTJMPREFf - Equivalent to PUSHREFCONT IFNOTJMP.26/126/51
E304CONDSELf x y - x or yIf 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
E305CONDSELCHKf x y - x or ySame as CONDSEL, but first checks whether x and y have the same type.26
E308IFRETALTf -Performs RETALT if integer f!=0.26
E309IFNOTRETALTf -Performs RETALT if integer f=0.26
E30D[ref] IFREFELSEf 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] IFELSEREFf c -Equivalent to PUSHREFCONT IFELSE.26/126/51
E30F[ref] [ref] IFREFELSEREFf -Equivalent to PUSHREFCONT PUSHREFCONT IFELSE.126/51
E39_n[n] IFBITJMPx c - xChecks 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] IFNBITJMPx c - xJumps to c if bit 0 <= n <= 31 is not set in integer x.26
E3D_n[ref] [n] IFBITJMPREFx - xPerforms a JMPREF if bit 0 <= n <= 31 is set in integer x.126/51
E3F_n[ref] [n] IFNBITJMPREFx - xPerforms 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
E4REPEATn 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
E4REPEAT:<{ code }>
<{ code }>REPEAT
n -Equivalent to <{ code }> CONT REPEAT.
E5REPEATEND
REPEAT:
n - Similar to REPEAT, but it is applied to the current continuation cc.18
E6UNTILc - 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
E6UNTIL:<{ code }>
<{ code }>UNTIL
-Equivalent to <{ code }> CONT UNTIL.
E7UNTILEND
UNTIL:
-Similar to UNTIL, but executes the current continuation cc in a loop. When the loop exit condition is satisfied, performs a RET.18
E8WHILEc' 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
E8WHILE:<{ cond }>DO<{ code }>-Equivalent to <{ cond }> CONT <{ code }> CONT WHILE.
E9WHILEENDc' - Similar to WHILE, but uses the current continuation cc as the loop body.18
EAAGAINc - 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
EAAGAIN:<{ code }>
<{ code }>AGAIN
-Equivalent to <{ code }> CONT AGAIN.
EBAGAINEND
AGAIN:
-Similar to AGAIN, but performed with respect to the current continuation cc.18
E314REPEATBRKn 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
E314REPEATBRK:<{ code }>
<{ code }>REPEATBRK
n -Equivalent to <{ code }> CONT REPEATBRK.
E315REPEATENDBRKn -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
E316UNTILBRKc -Similar to UNTIL, but also modifies c1 in the same way as REPEATBRK.26
E316UNTILBRK:<{ code }>-Equivalent to <{ code }> CONT UNTILBRK.
E317UNTILENDBRK
UNTILBRK:
-Equivalent to SAMEALTSAVE UNTILEND.26
E318WHILEBRKc' c -Similar to WHILE, but also modifies c1 in the same way as REPEATBRK.26
E318WHILEBRK:<{ cond }>DO<{ code }>-Equivalent to <{ cond }> CONT <{ code }> CONT WHILEBRK.
E319WHILEENDBRKc -Equivalent to SAMEALTSAVE WHILEEND.26
E31AAGAINBRKc -Similar to AGAIN, but also modifies c1 in the same way as REPEATBRK.26
E31AAGAINBRK:<{ code }>-Equivalent to <{ code }> CONT AGAINBRK.
E31BAGAINENDBRK
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] SETCONTARGSx_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] SETNUMARGSc - 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 SETCONTARGSx_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”
ED10RETURNVARARGSp -Similar to RETURNARGS, but with Integer 0 <= p <= 255 taken from the stack.26+s”
ED11SETCONTVARARGSx_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”
ED12SETNUMVARARGSc 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
ED1EBLESSs - cTransforms a Slice s into a simple ordinary continuation c, with c.code=s and an empty stack and savelist.26
ED1FBLESSVARARGSx_1...x_r s r n - cEquivalent to ROT BLESS ROTREV SETCONTVARARGS.26+s”
EErn[r] [n] BLESSARGSx_1...x_r s - c0 <= 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] BLESSNUMARGSs - cAlso 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
ED4ic[i] PUSHCTR
c[i] PUSH
- xPushes 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
ED44c4 PUSHCTR
c4 PUSH
- xPushes the “global data root'' cell reference, thus enabling access to persistent smart-contract data.26
ED5ic[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
ED54c4 POPCTR
c4 POP
x -Sets the “global data root'' cell reference, thus allowing modification of persistent smart-contract data.26
ED6ic[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
ED7ic[i] SETRETCTRx - Equivalent to c0 PUSHCTR c[i] SETCONTCTR c0 POPCTR.26
ED8ic[i] SETALTCTRx - Equivalent to c1 PUSHCTR c[i] SETCONTCTR c0 POPCTR.26
ED9ic[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
EDAic[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
EDBic[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
EDCic[i] SAVEBOTH
c[i] SAVEBOTHCTR
Equivalent to DUP c[i] SAVE c[i] SAVEALT.26
EDE0PUSHCTRXi - xSimilar 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
EDE1POPCTRXx i - Similar to c[i] POPCTR, but with 0 <= i <= 255 from the stack.26
EDE2SETCONTCTRXx c i - c'Similar to c[i] SETCONTCTR, but with 0 <= i <= 255 from the stack.26
EDF0COMPOS
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
EDF1COMPOSALT
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
EDF2COMPOSBOTHc 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
EDF3ATEXITc - Sets c0 to compose0(c, c0). In other words, c will be executed before exiting current subroutine.26
EDF3ATEXIT:<{ code }>
<{ code }>ATEXIT
-Equivalent to <{ code }> CONT ATEXIT.
EDF4ATEXITALTc - Sets c1 to compose1(c, c1). In other words, c will be executed before exiting current subroutine by its alternative return path.26
EDF4ATEXITALT:<{ code }>
<{ code }>ATEXITALT
-Equivalent to <{ code }> CONT ATEXITALT.
EDF5SETEXITALTc - 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
EDF6THENRETc - c'Computes compose0(c, c0).26
EDF7THENRETALTc - c'Computes compose0(c, c1)26
EDF8INVERT-Interchanges c0 and c1.26
EDF9BOOLEVALc - ?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
EDFASAMEALT-Sets c1 to c0. Equivalent to c0 PUSHCTR c1 POPCTR.26
EDFBSAMEALTSAVE-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
- nnCalls 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
- nFor 0 <= n < 2^14, an encoding of [n] CALL for larger values of n.
F16_n[n] JMP - nJumps 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 cEquivalent 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 nThrows 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] THROWIFf - Throws exception 0 <= n <= 63 with parameter zero only if integer f!=0.26/76
F2A_n[n] THROWIFNOTf - Throws exception 0 <= n <= 63 with parameter zero only if integer f=0.26/76
F2C4_n[n] THROW- 0 nnFor 0 <= n < 2^11, an encoding of [n] THROW for larger values of n.84
F2CC_n[n] THROWARGx - x nnThrows 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] THROWIFf - For 0 <= n < 2^11, an encoding of [n] THROWIF for larger values of n.34/84
F2DC_n[n] THROWARGIFx f - Throws exception 0 <= nn < 2^11 with parameter x only if integer f!=0.34/84
F2E4_n[n] THROWIFNOTf - For 0 <= n < 2^11, an encoding of [n] THROWIFNOT for larger values of n.34/84
F2EC_n[n] THROWARGIFNOTx f - Throws exception 0 <= n < 2^11 with parameter x only if integer f=0.34/84
F2F0THROWANYn - 0 nThrows exception 0 <= n < 2^16 with parameter zero.
Approximately equivalent to ZERO SWAP THROWARGANY.
76
F2F1THROWARGANYx n - x nThrows exception 0 <= n < 2^16 with parameter x, transferring control to the continuation in c2.
Approximately equivalent to c2 PUSHCTR 2 JMPXARGS.
76
F2F2THROWANYIFn f - Throws exception 0 <= n < 2^16 with parameter zero only if f!=0.26/76
F2F3THROWARGANYIFx n f - Throws exception 0 <= n<2^16 with parameter x only if f!=0.26/76
F2F4THROWANYIFNOTn f - Throws exception 0 <= n<2^16 with parameter zero only if f=0.26/76
F2F5THROWARGANYIFNOTx n f - Throws exception 0 <= n<2^16 with parameter x only if f=0.26/76
F2FFTRYc 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
F2FFTRY:<{ code1 }>CATCH<{ code2 }>-Equivalent to <{ code1 }> CONT <{ code2 }> CONT TRY.
F3pr[p] [r] TRYARGSc 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
6DNEWDICT - DReturns a new empty dictionary.
It is an alternative mnemonics for PUSHNULL.
18
6EDICTEMPTYD - ?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
CESTDICTS
``
s b - b'Stores a Slice-represented dictionary s into Builder b.
It is actually a synonym for STSLICE.
18
F400STDICT
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
F401SKIPDICT
SKIPOPTREF
s - s'Equivalent to LDDICT NIP.26
F402LDDICTSs - 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
F403PLDDICTSs - s'Preloads a (Slice-represented) dictionary s' from Slice s.
Approximately equivalent to LDDICTS DROP.
26
F404LDDICT
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
F405PLDDICT
PLDOPTREF
s - DPreloads a dictionary D from Slice s.
Approximately equivalent to LDDICT DROP.
26
F406LDDICTQs - D s' -1 or s 0A quiet version of LDDICT.26
F407PLDDICTQs - D -1 or 0A quiet version of PLDDICT.26

10.3 Get dictionary operations

xxxxxxx
Opcode
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fift syntax
xxxxxxxxxxxxxxxxx
Stack
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Description
xxxx
Gas
F40ADICTGETk D n - x -1 or 0Looks 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.
F40BDICTGETREFk D n - c -1 or 0Similar to DICTGET, but with a LDREF ENDS applied to x on success.
This operation is useful for dictionaries of type HashmapE(n,^Y).
F40CDICTIGETi D n - x -1 or 0Similar 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.
F40DDICTIGETREFi D n - c -1 or 0Combines DICTIGET with DICTGETREF: it uses signed n-bit Integer i as a key and returns a Cell instead of a Slice on success.
F40EDICTUGETi D n - x -1 or 0Similar to DICTIGET, but with unsigned (big-endian) n-bit Integer i used as a key.
F40FDICTUGETREFi D n - c -1 or 0Similar 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
F412DICTSETx 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'.
F413DICTSETREFc k D n - D'Similar to DICTSET, but with the value set to a reference to Cell c.
F414DICTISETx 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.
F415DICTISETREFc i D n - D'Similar to DICTSETREF, but with the key a signed n-bit integer as in DICTISET.
F416DICTUSETx i D n - D'Similar to DICTISET, but with i an unsigned n-bit integer.
F417DICTUSETREFc i D n - D'Similar to DICTISETREF, but with i unsigned.
F41ADICTSETGETx k D n - D' y -1 or D' 0Combines 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.
F41BDICTSETGETREFc k D n - D' c' -1 or D' 0Combines DICTSETREF with DICTGETREF similarly to DICTSETGET.
F41CDICTISETGETx i D n - D' y -1 or D' 0DICTISETGET, but with i a signed n-bit integer.
F41DDICTISETGETREFc i D n - D' c' -1 or D' 0DICTISETGETREF, but with i a signed n-bit integer.
F41EDICTUSETGETx i D n - D' y -1 or D' 0DICTISETGET, but with i an unsigned n-bit integer.
F41FDICTUSETGETREFc i D n - D' c' -1 or D' 0DICTISETGETREF, but with i an unsigned n-bit integer.
F422DICTREPLACEx k D n - D' -1 or D 0A 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.
F423DICTREPLACEREFc k D n - D' -1 or D 0A Replace counterpart of DICTSETREF.
F424DICTIREPLACEx i D n - D' -1 or D 0DICTREPLACE, but with i a signed n-bit integer.
F425DICTIREPLACEREFc i D n - D' -1 or D 0DICTREPLACEREF, but with i a signed n-bit integer.
F426DICTUREPLACEx i D n - D' -1 or D 0DICTREPLACE, but with i an unsigned n-bit integer.
F427DICTUREPLACEREFc i D n - D' -1 or D 0DICTREPLACEREF, but with i an unsigned n-bit integer.
F42ADICTREPLACEGETx k D n - D' y -1 or D 0A Replace counterpart of DICTSETGET: on success, also returns the old value associated with the key in question.
F42BDICTREPLACEGETREFc k D n - D' c' -1 or D 0A Replace counterpart of DICTSETGETREF.
F42CDICTIREPLACEGETx i D n - D' y -1 or D 0DICTREPLACEGET, but with i a signed n-bit integer.
F42DDICTIREPLACEGETREFc i D n - D' c' -1 or D 0DICTREPLACEGETREF, but with i a signed n-bit integer.
F42EDICTUREPLACEGETx i D n - D' y -1 or D 0DICTREPLACEGET, but with i an unsigned n-bit integer.
F42FDICTUREPLACEGETREFc i D n - D' c' -1 or D 0DICTREPLACEGETREF, but with i an unsigned n-bit integer.
F432DICTADDx k D n - D' -1 or D 0An 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.
F433DICTADDREFc k D n - D' -1 or D 0An Add counterpart of DICTSETREF.
F434DICTIADDx i D n - D' -1 or D 0DICTADD, but with i a signed n-bit integer.
F435DICTIADDREFc i D n - D' -1 or D 0DICTADDREF, but with i a signed n-bit integer.
F436DICTUADDx i D n - D' -1 or D 0DICTADD, but with i an unsigned n-bit integer.
F437DICTUADDREFc i D n - D' -1 or D 0DICTADDREF, but with i an unsigned n-bit integer.
F43ADICTADDGETx k D n - D' -1 or D y 0An 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.
F43BDICTADDGETREFc k D n - D' -1 or D c' 0An Add counterpart of DICTSETGETREF.
F43CDICTIADDGETx i D n - D' -1 or D y 0DICTADDGET, but with i a signed n-bit integer.
F43DDICTIADDGETREFc i D n - D' -1 or D c' 0DICTADDGETREF, but with i a signed n-bit integer.
F43EDICTUADDGETx i D n - D' -1 or D y 0DICTADDGET, but with i an unsigned n-bit integer.
F43FDICTUADDGETREFc i D n - D' -1 or D c' 0DICTADDGETREF, 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
F441DICTSETBb k D n - D'
F442DICTISETBb i D n - D'
F443DICTUSETBb i D n - D'
F445DICTSETGETBb k D n - D' y -1 or D' 0
F446DICTISETGETBb i D n - D' y -1 or D' 0
F447DICTUSETGETBb i D n - D' y -1 or D' 0
F449DICTREPLACEBb k D n - D' -1 or D 0
F44ADICTIREPLACEBb i D n - D' -1 or D 0
F44BDICTUREPLACEBb i D n - D' -1 or D 0
F44DDICTREPLACEGETBb k D n - D' y -1 or D 0
F44EDICTIREPLACEGETBb i D n - D' y -1 or D 0
F44FDICTUREPLACEGETBb i D n - D' y -1 or D 0
F451DICTADDBb k D n - D' -1 or D 0
F452DICTIADDBb i D n - D' -1 or D 0
F453DICTUADDBb i D n - D' -1 or D 0
F455DICTADDGETBb k D n - D' -1 or D y 0
F456DICTIADDGETBb i D n - D' -1 or D y 0
F457DICTUADDGETBb 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
F459DICTDELk D n - D' -1 or D 0Deletes 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.
F45ADICTIDELi 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'').
F45BDICTUDELi D n - D' ?Similar to DICTIDEL, but with i an unsigned n-bit integer.
F462DICTDELGETk D n - D' x -1 or D 0Deletes 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.
F463DICTDELGETREFk D n - D' c -1 or D 0Similar to DICTDELGET, but with LDREF ENDS applied to x on success, so that the value returned c is a Cell.
F464DICTIDELGETi D n - D' x -1 or D 0DICTDELGET, but with i a signed n-bit integer.
F465DICTIDELGETREFi D n - D' c -1 or D 0DICTDELGETREF, but with i a signed n-bit integer.
F466DICTUDELGETi D n - D' x -1 or D 0DICTDELGET, but with i an unsigned n-bit integer.
F467DICTUDELGETREFi D n - D' c -1 or D 0DICTDELGETREF, 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
F469DICTGETOPTREFk D n - c^?A variant of DICTGETREF that returns Null instead of the value c^? if the key k is absent from dictionary D.
F46ADICTIGETOPTREFi D n - c^?DICTGETOPTREF, but with i a signed n-bit integer. If the key i is out of range, also returns Null.
F46BDICTUGETOPTREFi D n - c^?DICTGETOPTREF, but with i an unsigned n-bit integer. If the key i is out of range, also returns Null.
F46DDICTSETGETOPTREFc^? 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).
F46EDICTISETGETOPTREFc^? 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.
F46FDICTUSETGETOPTREFc^? 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
F470PFXDICTSETx k D n - D' -1 or D 0
F471PFXDICTREPLACEx k D n - D' -1 or D 0
F472PFXDICTADDx k D n - D' -1 or D 0
F473PFXDICTDELk 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
F474DICTGETNEXTk D n - x' k' -1 or 0Computes 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).
F475DICTGETNEXTEQk D n - x' k' -1 or 0Similar to DICTGETNEXT, but computes the minimal key k' that is lexicographically greater than or equal to k.
F476DICTGETPREVk D n - x' k' -1 or 0Similar to DICTGETNEXT, but computes the maximal key k' lexicographically smaller than k.
F477DICTGETPREVEQk D n - x' k' -1 or 0Similar to DICTGETPREV, but computes the maximal key k' lexicographically smaller than or equal to k.
F478DICTIGETNEXTi D n - x' i' -1 or 0Similar 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).
F479DICTIGETNEXTEQi D n - x' i' -1 or 0Similar to DICTGETNEXTEQ, but interprets keys as signed n-bit integers.
F47ADICTIGETPREVi D n - x' i' -1 or 0Similar to DICTGETPREV, but interprets keys as signed n-bit integers.
F47BDICTIGETPREVEQi D n - x' i' -1 or 0Similar to DICTGETPREVEQ, but interprets keys as signed n-bit integers.
F47CDICTUGETNEXTi D n - x' i' -1 or 0Similar 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).
F47DDICTUGETNEXTEQi D n - x' i' -1 or 0Similar to DICTGETNEXTEQ, but interprets keys as unsigned n-bit integers.
F47EDICTUGETPREVi D n - x' i' -1 or 0Similar to DICTGETPREV, but interprets keys as unsigned n-bit integers.
F47FDICTUGETPREVEQi D n - x' i' -1 or 0Similar 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
F482DICTMIND n - x k -1 or 0Computes the minimal key k (represented by a Slice with n data bits) in dictionary D, and returns k along with the associated value x.
F483DICTMINREFD n - c k -1 or 0Similar to DICTMIN, but returns the only reference in the value as a Cell c.
F484DICTIMIND n - x i -1 or 0Similar 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.
F485DICTIMINREFD n - c i -1 or 0Similar to DICTIMIN, but returns the only reference in the value.
F486DICTUMIND n - x i -1 or 0Similar to DICTMIN, but returns the key as an unsigned n-bit Integer i.
F487DICTUMINREFD n - c i -1 or 0Similar to DICTUMIN, but returns the only reference in the value.
F48ADICTMAXD n - x k -1 or 0Computes the maximal key k (represented by a Slice with n data bits) in dictionary D, and returns k along with the associated value x.
F48BDICTMAXREFD n - c k -1 or 0Similar to DICTMAX, but returns the only reference in the value.
F48CDICTIMAXD n - x i -1 or 0Similar 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.
F48DDICTIMAXREFD n - c i -1 or 0Similar to DICTIMAX, but returns the only reference in the value.
F48EDICTUMAXD n - x i -1 or 0Similar to DICTMAX, but returns the key as an unsigned n-bit Integer i.
F48FDICTUMAXREFD n - c i -1 or 0Similar to DICTUMAX, but returns the only reference in the value.
F492DICTREMMIND n - D' x k -1 or D 0Computes 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'.
F493DICTREMMINREFD n - D' c k -1 or D 0Similar to DICTREMMIN, but returns the only reference in the value as a Cell c.
F494DICTIREMMIND n - D' x i -1 or D 0Similar 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.
F495DICTIREMMINREFD n - D' c i -1 or D 0Similar to DICTIREMMIN, but returns the only reference in the value.
F496DICTUREMMIND n - D' x i -1 or D 0Similar to DICTREMMIN, but returns the key as an unsigned n-bit Integer i.
F497DICTUREMMINREFD n - D' c i -1 or D 0Similar to DICTUREMMIN, but returns the only reference in the value.
F49ADICTREMMAXD n - D' x k -1 or D 0Computes 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'.
F49BDICTREMMAXREFD n - D' c k -1 or D 0Similar to DICTREMMAX, but returns the only reference in the value as a Cell c.
F49CDICTIREMMAXD n - D' x i -1 or D 0Similar 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.
F49DDICTIREMMAXREFD n - D' c i -1 or D 0Similar to DICTIREMMAX, but returns the only reference in the value.
F49EDICTUREMMAXD n - D' x i -1 or D 0Similar to DICTREMMAX, but returns the key as an unsigned n-bit Integer i.
F49FDICTUREMMAXREFD n - D' c i -1 or D 0Similar 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
F4A0DICTIGETJMPi 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.
F4A1DICTUGETJMPi D n - Similar to DICTIGETJMP, but performs DICTUGET instead of DICTIGET.
F4A2DICTIGETEXECi D n - Similar to DICTIGETJMP, but with EXECUTE instead of JMPX.
F4A3DICTUGETEXECi D n - Similar to DICTUGETJMP, but with EXECUTE instead of JMPX.
F4A6_n[ref] [n] DICTPUSHCONST - D nPushes 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
F4A8PFXDICTGETQs D n - s' x s'' -1 or s 0Looks 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.
F4A9PFXDICTGETs D n - s' x s''Similar to PFXDICTGET, but throws a cell deserialization failure exception on failure.
F4AAPFXDICTGETJMPs D n - s' s'' or sSimilar 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.
F4ABPFXDICTGETEXECs 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 sCombines [n] DICTPUSHCONST for 0 <= n <= 1023 with PFXDICTGETJMP.
F4BCDICTIGETJMPZi D n - i or nothingA variant of DICTIGETJMP that returns index i on failure.
F4BDDICTUGETJMPZi D n - i or nothingA variant of DICTUGETJMP that returns index i on failure.
F4BEDICTIGETEXECZi D n - i or nothingA variant of DICTIGETEXEC that returns index i on failure.
F4BFDICTUGETEXECZi D n - i or nothingA 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
F4B1SUBDICTGETk 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'.
F4B2SUBDICTIGETx l D n - D'Variant of SUBDICTGET with the prefix represented by a signed big-endian l-bit Integer x, where necessarily l <= 257.
F4B3SUBDICTUGETx l D n - D'Variant of SUBDICTGET with the prefix represented by an unsigned big-endian l-bit Integer x, where necessarily l <= 256.
F4B5SUBDICTRPGETk 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).
F4B6SUBDICTIRPGETx l D n - D'Variant of SUBDICTRPGET with the prefix represented by a signed big-endian l-bit Integer x, where necessarily l <= 257.
F4B7SUBDICTURPGETx 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

xxxxxxx
Opcode
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fift syntax
xxxxxxxxxxxxxxxxx
Stack
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Description
xxxx
Gas
F800ACCEPT-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
F801SETGASLIMITg - 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
F80FCOMMIT-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
F810RANDU256- xGenerates 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\|
F811RANDy - zGenerates 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\|
F814SETRANDx - Sets the random seed to unsigned 256-bit Integer x.26+\|c7\|+\|c1_1\|
F815ADDRAND
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 - xReturns 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
F823NOW - xReturns 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
F824BLOCKLT - xReturns the starting logical time of the current block.
Equivalent to 4 GETPARAM.
26
F825LTIME - xReturns the logical time of the current transaction.
Equivalent to 5 GETPARAM.
26
F826RANDSEED - xReturns the current random seed as an unsigned 256-bit Integer.
Equivalent to 6 GETPARAM.
26
F827BALANCE - tReturns 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
F828MYADDR - sReturns 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
F829CONFIGROOT - DReturns the Maybe Cell D with the current global configuration dictionary. Equivalent to 9 GETPARAM .26
F830CONFIGDICT - D 32Returns the global configuration dictionary along with its key length (32).
Equivalent to CONFIGROOT 32 PUSHINT.
26
F832CONFIGPARAMi - c -1 or 0Returns 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.
F833CONFIGOPTPARAMi - 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
F840GETGLOBVARk - xReturns the k-th global variable for 0 <= k < 255.
Equivalent to c7 PUSHCTR SWAP INDEXVARQ.
26
F85_k[k] GETGLOB - xReturns the k-th global variable for 1 <= k <= 31.
Equivalent to c7 PUSHCTR [k] INDEXQ.
26
F860SETGLOBVARx 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] SETGLOBx - 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
F900HASHCUc - xComputes 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
F901HASHSUs - xComputes 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
F902SHA256Us - xComputes 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
F910CHKSIGNUh 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
F911CHKSIGNSd 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
F940CDATASIZEQc n - x y z -1 or 0Recursively 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.
F941CDATASIZEc n - x y zA non-quiet version of CDATASIZEQ that throws a cell overflow exception (8) on failure.
F942SDATASIZEQs n - x y z -1 or 0Similar 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.
F943SDATASIZEs n - x y zA 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
FA00LDGRAMS
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
FA01LDVARINT16s - x s'Similar to LDVARUINT16, but loads a signed Integer x.
Approximately equivalent to 4 LDU SWAP 3 LSHIFT# LDIX.
26
FA02STGRAMS
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
FA03STVARINT16b 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
FA40LDMSGADDRs - 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
FA41LDMSGADDRQs - s' s'' -1 or s 0A quiet version of LDMSGADDR: on success, pushes an extra -1; on failure, pushes the original s and a zero.26
FA42PARSEMSGADDRs - tDecomposes 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
FA43PARSEMSGADDRQs - t -1 or 0A quiet version of PARSEMSGADDR: returns a zero on error instead of throwing an exception.26
FA44REWRITESTDADDRs - x yParses 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
FA45REWRITESTDADDRQs - x y -1 or 0A quiet version of primitive REWRITESTDADDR.26
FA46REWRITEVARADDRs - 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
FA47REWRITEVARADDRQs - x s' -1 or 0A 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
FB00SENDRAWMSGc 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
FB02RAWRESERVEx 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
FB03RAWRESERVEXx 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
FB04SETCODEc - 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
FB06SETLIBCODEc 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
FB07CHANGELIBh 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 < 24026
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
FE00DUMPSTK-Dumps the stack (at most the top 255 values) and shows the total stack depth.26
FE2is[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
FF00SETCP0-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
FFF0SETCPXc - Selects codepage c with -2^15 <= c < 2^15 passed in the top of the stack.26