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Merge pull request #126 from 0xPolygonHermez/feature/updateArithOpcodes
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Feature/update arith opcodes
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@ignasirv
ignasirv authored Sep 7, 2022
2 parents f2a2489 + 8e45dd4 commit 09b2ec3
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213 changes: 149 additions & 64 deletions main/opcodes.zkasm
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Original file line number Diff line number Diff line change
Expand Up @@ -30,13 +30,11 @@ opADD:
SP - 2 :JMPN(stackUnderflow)
SP - 1 => SP
$ => A :MLOAD(SP--)
$ => C :MLOAD(SP)
$ => B :MLOAD(SP)

; Add operation with Arith
A :MSTORE(arithA)
C :MSTORE(arithB)
:CALL(addARITH)
$ => E :MLOAD(arithRes1)
$ => E :ADD

E :MSTORE(SP++)
1024 - SP :JMPN(stackOverflow)
GAS-3 => GAS :JMPN(outOfGas)
Expand Down Expand Up @@ -68,15 +66,10 @@ opSUB:

SP - 2 :JMPN(stackUnderflow)
SP - 1 => SP
$ => E :MLOAD(SP--)
$ => C :MLOAD(SP)
; Sub operation with Arith
E :MSTORE(arithA)
C :MSTORE(arithB)
:CALL(subARITH)
$ => A :MLOAD(arithRes1)
A :MSTORE(SP++)
1024 - SP :JMPN(stackOverflow)
$ => A :MLOAD(SP--)
$ => B :MLOAD(SP)
$ => E :SUB
E :MSTORE(SP++)
GAS-3 => GAS :JMPN(outOfGas)
:JMP(readCode)

Expand Down Expand Up @@ -213,53 +206,148 @@ opSMODNeg:
opADDMOD:

%MAX_CNT_ARITH - CNT_ARITH - 1 :JMPN(outOfCounters)
%MAX_CNT_BINARY - CNT_BINARY - 3 :JMPN(outOfCounters)
%MAX_CNT_STEPS - STEP - 120 :JMPN(outOfCounters)
%MAX_CNT_BINARY - CNT_BINARY - 4 :JMPN(outOfCounters)
%MAX_CNT_STEPS - STEP - 80 :JMPN(outOfCounters)

GAS-8 => GAS :JMPN(outOfGas)

SP - 3 :JMPN(stackUnderflow)
SP - 1 => SP
$ => A :MLOAD(SP--)
$ => B :MLOAD(SP--)
; Add operation with Arith
A :MSTORE(arithA)
B :MSTORE(arithB)
:CALL(addARITH)
$ => E :MLOAD(arithRes1)
$ => A :MLOAD(SP)
; Div operation with Arith
E :MSTORE(arithA)
A :MSTORE(arithB)
:CALL(divARITH)
$ => C :MLOAD(arithRes2)
${var _addMod = A + B} ; TODO $$

1 => D
$ => A :ADD, JMPC(AddModJumpCarry) ; or arith
0 => D

AddModJumpCarry:
A => E ; Store sumResult on E

$ => A :MLOAD(SP) ; load modulus
2 => B
$ :LT, JMPC(zeroOneMod)

${_addMod / A} => B ; k: Max should be (2^256 -1) * 2 / 2 --> smaller than 2^256
${_addMod % A} => C ; addModResult

; k * N + addModResult = D*2^256 + sumResult
; B * A + C = D*2^256 + E

; Check addModResult is less than modulus
E :ARITH

A => B ; modulus
C => A ; addModResult
$ => A :LT
1 :ASSERT
C :MSTORE(SP++)
1024 - SP :JMPN(stackOverflow)
GAS-8 => GAS :JMPN(outOfGas)
:JMP(readCode)

opMULMOD:
%MAX_CNT_ARITH - CNT_ARITH - 3 :JMPN(outOfCounters)
%MAX_CNT_BINARY - CNT_BINARY - 3 :JMPN(outOfCounters)
%MAX_CNT_STEPS - STEP - 150 :JMPN(outOfCounters)

%MAX_CNT_ARITH - CNT_ARITH - 2 :JMPN(outOfCounters)
%MAX_CNT_BINARY - CNT_BINARY - 2 :JMPN(outOfCounters)
%MAX_CNT_STEPS - STEP - 120 :JMPN(outOfCounters)

GAS-8 => GAS :JMPN(outOfGas)
SP - 3 :JMPN(stackUnderflow)
SP - 1 => SP

; The following approahc will be followed in order to verify the mulmod operation
; A * B + 0 = D*2^256 + E
; K * N + mulModResult = D*2^256 + E

; Since the k can be bigger than 2²⁵⁶ and therefore does not fit in a register we divedit in the
; most significan and less significant part:

; (k.l + k.h * 2²⁵⁶) * N + mulModResult = (D1 + D2) * 2²⁵⁶ + E
; And divide this operation in 2 which fits in 2²⁵⁶ digits

;k.l * N + mulModResult = D1 * 2²⁵⁶ + E
;k.h * 2²⁵⁶ * N = D2 * 2²⁵⁶ --> k.h * N = D2
$ => A :MLOAD(SP--)
$ => B :MLOAD(SP--)

; Mul operation with Arith
${var _mulMod = A * B} ; TODO $$
A :MSTORE(arithA)
B :MSTORE(arithB)
; here we perform the: A * B + 0 = D*2^256 + E
; result is stored in: arithRes1(E) and arithOverflow(D)
:CALL(mulARITH)
$ => E :MLOAD(arithRes1)
$ => A :MLOAD(SP)
; Div operation with Arith
E :MSTORE(arithA)
A :MSTORE(arithB)
:CALL(divARITH)
$ => C :MLOAD(arithRes2)

$ => A :MLOAD(SP) ; Modulus N
; Check if modulus is 0 or 1
2 => B
$ :LT, JMPC(zeroOneMod)

; Now we will try to perform the following equation:
; (k.l + k.h * 2²⁵⁶) * N + mulModResult = (D1 + D2) * 2²⁵⁶ + E
A => C ; modulus on C
${(_mulMod / C) >> 256} => B ; k.h
; We can jump with Js, because later it's all verified by the ARITH
${cond(B == 0)} :JMPN(mulModNoKH)

; Since there's k.h we will split the equation in those 2
;k.l * N + mulModResult = D1 * 2²⁵⁶ + E
;k.h * 2²⁵⁶ * N = D2 * 2²⁵⁶ --> k.h * N = D2

; k.h * N = D2
; B * A + 0 = 0 * 2²⁵⁶ + E
; D2 must be less than 2²⁵⁶
C => A ; Modulus
0 => C, D
${B * A} => E :MSTORE(tmpVarD), ARITH ; D2

; k.l * N + mulModResult = D1 * 2²⁵⁶ + E
; B * A + C = D*2^256 + E
; remember that:
; result of mul is stored in: arithRes1(E) and arithOverflow(D)

${(_mulMod / A) % (2 << 256)} => B ; k.l
${_mulMod % A} => C ; mulModResult
${(B * A + C) >> 256} => D ; D1
$ :MLOAD(arithRes1), ARITH

; Finally we need to assert the following:
; N>resultModulus
; D1 + D2 = D

; N>resultModulus ; LT; ASSERT
A => B ; modulus
C => A ; mulModResult
$ => A :LT
1 :ASSERT

; Assert D1 + D2 = D ; ADD ;ASSERT
D => A ; D1
$ => B :MLOAD(tmpVarD) ;D2
$ => A :ADD
$ :MLOAD(arithOverflow), ASSERT

C :MSTORE(SP++)
1024 - SP :JMPN(stackOverflow)
GAS-8 => GAS :JMPN(outOfGas)
:JMP(readCode)

mulModNoKH:
; if theres no K.h the equation is simplified as:
; K * N + mulModResult = D*2^256 + E
; B * A + C = D*2^256 + E

C => A ; Modulus on A
${(_mulMod / A)} => B ; k
${_mulMod % A} => C ; mulModResult
$ => D :MLOAD(arithOverflow)
$ :MLOAD(arithRes1), ARITH ; Can this be on the same line of MLOAD?

A => B ; modulus
C => A ; mulModResult
$ => A :LT
1 :ASSERT
C :MSTORE(SP++)
:JMP(readCode)
zeroOneMod:
0 :MSTORE(SP++)
:JMP(readCode)

opEXP: ; //TODO: test exp == 0
Expand All @@ -286,32 +374,31 @@ opSIGNEXTEND: ; following this impl https://github.com/ethereumjs/ethereumjs-mon

SP - 2 :JMPN(stackUnderflow)
SP - 1 => SP
$ => A :MLOAD(SP--)
$ => D :MLOAD(SP)
31 => B
$ => B :LT
B - 1 :JMPN(opSIGNEXTENDEnd)
D => B
; Add operation with Arith
${A * 8} :MSTORE(arithA)
7 :MSTORE(arithB)
:CALL(addARITH)
$ => A :MLOAD(arithRes1)
${exp(2, A)} => C ; signBit
C => A
$ => B :AND
$ => B :MLOAD(SP--) ; sign byte --> sign bit = 8 * A + 7
$ => D :MLOAD(SP) ; number to convert
30 => A
$ :LT, JMPC(opSIGNEXTENDEnd); if signByte is 31 or more, means basically let the number as it is
; TODO we could divide this opcode in a table with constants, only 31 cases
B * 8 + 7 => B ; B is less than 31, no need for binary
${exp(2, B)} => A ; signBit TODO table for shifting + multipliyng

;Store mask
1 => B
$ => C :SUB ; mask

D => B ; number to convert
$ => B :AND ; check sign bit
0 => A
$ => A :LT
A - 1 :JMPN(opSIGNEXTENDPositive) ; 0 if negative, -1 if positive
C - 1 => A
0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFn => B
$ => B :XOR
$ :EQ, JMPC(opSIGNEXTENDPositive) ; If 0 means the sign bit was 0 --> positive
C => A ; mask
0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffn => B
$ => B :XOR ; not mask
D => A
$ => D :OR
:JMP(opSIGNEXTENDEnd)

opSIGNEXTENDPositive:
C - 1 => B
C => B
D => A
$ => D :AND

Expand Down Expand Up @@ -793,7 +880,7 @@ opCALLDATACOPYinit:
$ => SP :MLOAD(SPw)
$ => C :MLOAD(SP) ;length
C - 32 => C
C :MSTORE(SP)
C :MSTORE(SP)
B + 32 => B
:JMP(opCALLDATACOPYinit)

Expand Down Expand Up @@ -3281,8 +3368,6 @@ opSTATICCALL:
:CALL(copySP)
:JMP(txType)

; TODO logs, creates (shpoudl revert the call also?), calls(back to initSR)
; TODO memExpansion just like Return
opREVERT:

%MAX_CNT_STEPS - STEP - 600 :JMPN(outOfCounters)
Expand Down
9 changes: 6 additions & 3 deletions main/utils.zkasm
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@ VAR GLOBAL arithA
VAR GLOBAL arithB
VAR GLOBAL arithRes1
VAR GLOBAL arithRes2
VAR GLOBAL arithOverflow
VAR GLOBAL tmpZkPC
VAR GLOBAL tmpZkPC2

Expand Down Expand Up @@ -400,7 +401,7 @@ subARITH:
$ => B :MLOAD(arithB)
$ => A :SUB

A :MSTORE(arithRes1)
A :MSTORE(arithRes1)

zkPC+1 => RR :JMP(loadTmp)
$ => RR :MLOAD(tmpZkPC)
Expand All @@ -414,10 +415,12 @@ mulARITH:
$ => A :MLOAD(arithA)
$ => B :MLOAD(arithB)
0 => C
0 => D
${A*B} => E :ARITH
$${var _mulArith = A * B}
${_mulArith >> 256} => D
${_mulArith} => E :ARITH

E :MSTORE(arithRes1)
D :MSTORE(arithOverflow)

zkPC+1 => RR :JMP(loadTmp)
$ => RR :MLOAD(tmpZkPC)
Expand Down

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