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EIP 7823, 7883: ModExp precompile update #2833

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0e1680a
implement eip-7883
anvacaru Dec 16, 2025
1be2418
Merge branch 'master' into eip-7883
anvacaru Dec 16, 2025
892ef68
eip-7823: modexp upper bounds
anvacaru Dec 16, 2025
8dc9013
update failing.llvm file
anvacaru Dec 16, 2025
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13 changes: 13 additions & 0 deletions kevm-pyk/src/kevm_pyk/kproj/evm-semantics/evm.md
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Original file line number Diff line number Diff line change
Expand Up @@ -2254,6 +2254,19 @@ Precompiled Contracts
rule <k> MODEXP => #end EVMC_SUCCESS ... </k>
<callData> DATA </callData>
<output> _ => #modexp1(#asWord(#range(DATA, 0, 32)), #asWord(#range(DATA, 32, 32)), #asWord(#range(DATA, 64, 32)), #range(DATA, 96, maxInt(0, lengthBytes(DATA) -Int 96))) </output>
<schedule> SCHED </schedule>
requires notBool Ghaseip7823 << SCHED >>
orBool modexpUBCheck(#asWord(#range(DATA, 0, 32)), #asWord(#range(DATA, 32, 32)), #asWord(#range(DATA, 64, 32)))

rule <k> MODEXP => #end EVMC_PRECOMPILE_FAILURE ... </k>
<callData> DATA </callData>
<schedule> SCHED </schedule>
requires Ghaseip7823 << SCHED >>
andBool notBool modexpUBCheck(#asWord(#range(DATA, 0, 32)), #asWord(#range(DATA, 32, 32)), #asWord(#range(DATA, 64, 32)))

syntax Bool ::= modexpUBCheck (Int , Int , Int) [symbol(modexpUBCheck), function, total]
// ----------------------------------------------------------------------------------------
rule modexpUBCheck(BASELEN, EXPLEN, MODLEN) => BASELEN <=Int 1024 andBool EXPLEN <=Int 1024 andBool MODLEN <=Int 1024

syntax Bytes ::= #modexp1 ( Int , Int , Int , Bytes ) [symbol(#modexp1), function]
| #modexp2 ( Int , Int , Int , Bytes ) [symbol(#modexp2), function]
Expand Down
30 changes: 19 additions & 11 deletions kevm-pyk/src/kevm_pyk/kproj/evm-semantics/gas.md
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Expand Up @@ -204,12 +204,16 @@ module GAS-FEES
rule [Cextcodecopy.new]: Cextcodecopy(SCHED, WIDTH) => Gcopy < SCHED > *Int (WIDTH up/Int 32) requires Ghasaccesslist << SCHED >> [concrete]
rule [Cextcodecopy.old]: Cextcodecopy(SCHED, WIDTH) => Gextcodecopy < SCHED > +Int (Gcopy < SCHED > *Int (WIDTH up/Int 32)) requires notBool Ghasaccesslist << SCHED >> [concrete]

rule [Cmodexp.old]: Cmodexp(SCHED, DATA, BASELEN, EXPLEN, MODLEN) => #multComplexity(maxInt(BASELEN, MODLEN)) *Int maxInt(#adjustedExpLength(BASELEN, EXPLEN, DATA), 1) /Int Gquaddivisor < SCHED >
requires notBool Ghasaccesslist << SCHED >>
rule [Cmodexp.old]: Cmodexp(SCHED, DATA, BASELEN, EXPLEN, MODLEN) => #multComplexity(maxInt(BASELEN, MODLEN)) *Int maxInt(#adjustedExpLength(BASELEN, EXPLEN, DATA, Gmodexpmultiplier < SCHED >), 1) /Int Gquaddivisor < SCHED >
requires notBool ( Ghasaccesslist << SCHED >> orBool Ghaseip7823 << SCHED >>)
[concrete]

rule [Cmodexp.new]: Cmodexp(SCHED, DATA, BASELEN, EXPLEN, MODLEN) => maxInt(200, (#newMultComplexity(maxInt(BASELEN, MODLEN)) *Int maxInt(#adjustedExpLength(BASELEN, EXPLEN, DATA), 1)) /Int Gquaddivisor < SCHED > )
requires Ghasaccesslist << SCHED >>
rule [Cmodexp.new]: Cmodexp(SCHED, DATA, BASELEN, EXPLEN, MODLEN) => maxInt(Gmodexpmin < SCHED >, (#newMultComplexity(maxInt(BASELEN, MODLEN)) *Int maxInt(#adjustedExpLength(BASELEN, EXPLEN, DATA, Gmodexpmultiplier < SCHED >), 1)) /Int Gquaddivisor < SCHED > )
requires Ghasaccesslist << SCHED >> andBool notBool Ghaseip7823 << SCHED >>
[concrete]

rule [Cmodexp.osaka]: Cmodexp(SCHED, DATA, BASELEN, EXPLEN, MODLEN) => maxInt(Gmodexpmin < SCHED >, (#multComplexityEIP7883(maxInt(BASELEN, MODLEN)) *Int maxInt(#adjustedExpLength(BASELEN, EXPLEN, DATA, Gmodexpmultiplier < SCHED >), 1)))
requires Ghaseip7823 << SCHED >>
[concrete]

rule [Cinitcode.new]: Cinitcode(SCHED, INITCODELEN) => Ginitcodewordcost < SCHED > *Int ( INITCODELEN up/Int 32 ) requires Ghasmaxinitcodesize << SCHED >> [concrete]
Expand Down Expand Up @@ -259,19 +263,23 @@ module GAS-FEES
// -----------------------------------------------------------------------
rule G*(GAVAIL, GLIMIT, REFUND, SCHED) => GAVAIL +Gas minGas((GLIMIT -Gas GAVAIL) /Gas Rmaxquotient < SCHED >, REFUND)

syntax Int ::= #multComplexity(Int) [symbol(#multComplexity), function]
| #newMultComplexity(Int) [symbol(#newMultComplexity), function]
// -----------------------------------------------------------------------------
syntax Int ::= #multComplexity(Int) [symbol(#multComplexity), function]
| #newMultComplexity(Int) [symbol(#newMultComplexity), function]
| #multComplexityEIP7883(Int) [symbol(#multComplexityEIP7883), function]
// -------------------------------------------------------------------------------------
rule #multComplexity(X) => X *Int X requires X <=Int 64
rule #multComplexity(X) => X *Int X /Int 4 +Int 96 *Int X -Int 3072 requires X >Int 64 andBool X <=Int 1024
rule #multComplexity(X) => X *Int X /Int 16 +Int 480 *Int X -Int 199680 requires X >Int 1024

rule #newMultComplexity(X) => (X up/Int 8) ^Int 2

syntax Int ::= #adjustedExpLength(Int, Int, Bytes) [symbol(#adjustedExpLength), function]
| #adjustedExpLength(Int) [symbol(#adjustedExpLengthAux), function]
// --------------------------------------------------------------------------------------------
rule #adjustedExpLength(BASELEN, EXPLEN, DATA) => #if EXPLEN <=Int 32 #then 0 #else 8 *Int (EXPLEN -Int 32) #fi +Int #adjustedExpLength(#asInteger(#range(DATA, 96 +Int BASELEN, minInt(EXPLEN, 32))))
rule #multComplexityEIP7883(X) => 16 requires X <=Int 32
rule #multComplexityEIP7883(X) => 2 *Int (((X +Int 7) /Int 8) ^Int 2) requires 32 <Int X

syntax Int ::= #adjustedExpLength(Int, Int, Bytes, Int) [symbol(#adjustedExpLength), function]
| #adjustedExpLength(Int) [symbol(#adjustedExpLengthAux), function]
// -------------------------------------------------------------------------------------------------
rule #adjustedExpLength(BASELEN, EXPLEN, DATA, MODEXPMULTIPLIER) => #if EXPLEN <=Int 32 #then 0 #else MODEXPMULTIPLIER *Int (EXPLEN -Int 32) #fi +Int #adjustedExpLength(#asInteger(#range(DATA, 96 +Int BASELEN, minInt(EXPLEN, 32))))

rule #adjustedExpLength(0) => 0
rule #adjustedExpLength(1) => 0
Expand Down
30 changes: 21 additions & 9 deletions kevm-pyk/src/kevm_pyk/kproj/evm-semantics/schedule.md
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Expand Up @@ -31,8 +31,8 @@ module SCHEDULE
| "Ghaswarmcoinbase" | "Ghaswithdrawals" | "Ghastransient" | "Ghasmcopy"
| "Ghasbeaconroot" | "Ghaseip6780" | "Ghasblobbasefee" | "Ghasblobhash"
| "Ghasbls12msmdiscount" | "Ghashistory" | "Ghasrequests" | "Ghasauthority"
| "Ghasfloorcost" | "Ghasclz"
// -------------------------------------------------------------
| "Ghasfloorcost" | "Ghasclz" | "Ghaseip7823"
// --------------------------------------------------------------------------------------
```

### Schedule Constants
Expand All @@ -53,8 +53,8 @@ A `ScheduleConst` is a constant determined by the fee schedule.
| "Gaccessliststoragekey" | "Rmaxquotient" | "Ginitcodewordcost" | "maxInitCodeSize" | "Gwarmstoragedirtystore"
| "Gpointeval" | "Gmaxblobgas" | "Gminbasefee" | "Gtargetblobgas" | "Gperblob" | "Blobbasefeeupdatefraction"
| "Gbls12g1add" | "Gbls12g1mul" | "Gbls12g2add" | "Gbls12g2mul" | "Gbls12mapfptog1" | "Gbls12PairingCheckMul"
| "Gbls12PairingCheckAdd" | "Gauthbase" | "Gbls12mapfp2tog2" | "Gtxdatafloor"
// -------------------------------------------------------------------------------------------------------------------------------------------------------
| "Gbls12PairingCheckAdd" | "Gauthbase" | "Gbls12mapfp2tog2" | "Gtxdatafloor" | "Gmodexpmultiplier" | "Gmodexpmin"
// --------------------------------------------------------------------------------------------------------------------------------------------------------------
```

### Default Schedule
Expand Down Expand Up @@ -149,6 +149,9 @@ A `ScheduleConst` is a constant determined by the fee schedule.
rule [Gbls12mapfptog1Default]: Gbls12mapfptog1 < DEFAULT > => 0
rule [Gbls12mapfp2tog2Default]: Gbls12mapfp2tog2 < DEFAULT > => 0

rule [GmodexpmultiplierDefault]: Gmodexpmultiplier < DEFAULT > => 8
rule [GmodexpminDefault]: Gmodexpmin < DEFAULT > => 200

rule [GselfdestructnewaccountDefault]: Gselfdestructnewaccount << DEFAULT >> => false
rule [GstaticcalldepthDefault]: Gstaticcalldepth << DEFAULT >> => true
rule [GemptyisnonexistentDefault]: Gemptyisnonexistent << DEFAULT >> => false
Expand Down Expand Up @@ -183,6 +186,7 @@ A `ScheduleConst` is a constant determined by the fee schedule.
rule [GhasauthorityDefault]: Ghasauthority << DEFAULT >> => false
rule [GhasfloorcostDefault]: Ghasfloorcost << DEFAULT >> => false
rule [GhasclzDefault]: Ghasclz << DEFAULT >> => false
rule [Ghaseip7823Default]: Ghaseip7823 << DEFAULT >> => false
```

### Frontier Schedule
Expand Down Expand Up @@ -504,11 +508,19 @@ A `ScheduleConst` is a constant determined by the fee schedule.
```k
syntax Schedule ::= "OSAKA" [symbol(OSAKA_EVM), smtlib(schedule_OSAKA)]
// -----------------------------------------------------------------------
rule [SCHEDCONSTOsaka]: SCHEDCONST < OSAKA > => SCHEDCONST < PRAGUE >

rule [GhasclzOsaka]: Ghasclz << OSAKA >> => true
rule [SCHEDFLAGOsaka]: SCHEDFLAG << OSAKA >> => SCHEDFLAG << PRAGUE >>
requires notBool ( SCHEDFLAG ==K Ghasclz )
rule [GmodexpmultiplierOsaka]: Gmodexpmultiplier < OSAKA > => 16
rule [GmodexpminOsaka]: Gmodexpmin < OSAKA > => 500
rule [GquaddivisorOsaka]: Gquaddivisor < OSAKA > => 1
rule [SCHEDCONSTOsaka]: SCHEDCONST < OSAKA > => SCHEDCONST < PRAGUE >
requires notBool ( SCHEDCONST ==K Gmodexpmultiplier
orBool SCHEDCONST ==K Gmodexpmin
orBool SCHEDCONST ==K Gquaddivisor )

rule [GhasclzOsaka]: Ghasclz << OSAKA >> => true
rule [Ghaseip7823Osaka]: Ghaseip7823 << OSAKA >> => true
rule [SCHEDFLAGOsaka]: SCHEDFLAG << OSAKA >> => SCHEDFLAG << PRAGUE >>
requires notBool ( SCHEDFLAG ==K Ghasclz
orBool SCHEDFLAG ==K Ghaseip7823 )

```

Expand Down
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