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Minor update to slot updates to align with tutorial #2647

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Oct 17, 2024
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Minor update to slot updates to align with tutorial #2647

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28 changes: 14 additions & 14 deletions kevm-pyk/src/kevm_pyk/kproj/evm-semantics/lemmas/slot-updates.k
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Original file line number Diff line number Diff line change
Expand Up @@ -36,43 +36,43 @@ module SLOT-UPDATES [symbolic]
A |Int #asWord ( B1 +Bytes B2 ) =>
#asWord ( #buf ( 32 -Int lengthBytes(B2), (A /Int (2 ^Int (8 *Int lengthBytes(B2)))) |Int #asWord ( B1 ) ) +Bytes B2 )
requires #rangeUInt(256, A) andBool A modInt (2 ^Int (8 *Int lengthBytes(B2))) ==Int 0 andBool lengthBytes(B1 +Bytes B2) <=Int 32
[simplification, preserves-definedness]
[simplification(40), comm, preserves-definedness]

// 2b. |Int of +Bytes, update to be done in right
rule [bor-update-to-right]:
A |Int #asWord ( B1 +Bytes B2 ) =>
#asWord ( B1 +Bytes #buf ( lengthBytes(B2), A |Int #asWord ( B2 ) ) )
requires 0 <=Int A andBool A <Int 2 ^Int (8 *Int lengthBytes(B2)) andBool lengthBytes(B2) <=Int 32
[simplification, preserves-definedness]
[simplification(40), comm, preserves-definedness]

// 3a. Update with explicit shift and symbolic slot
rule [bor-update-with-shift]:
( SHIFT *Int X ) |Int Y => #asWord ( #buf( 32 -Int ( log2Int(SHIFT) /Int 8 ), X ) +Bytes #buf( log2Int(SHIFT) /Int 8, Y ) )
requires #isByteShift(SHIFT)
andBool 0 <=Int X andBool X <Int 2 ^Int (8 *Int (32 -Int ( log2Int(SHIFT) /Int 8 )))
andBool 0 <=Int Y andBool Y <Int SHIFT
[simplification, concrete(SHIFT), comm, preserves-definedness]
[simplification(42), concrete(SHIFT), comm, preserves-definedness]

// 3b. Buffer cropping
// 3b. Update with implicit shift and symbolic slot
rule [bor-update-without-shift]:
X |Int Y => #asWord ( #buf ( 32 -Int #getFirstOneBit(X) /Int 8, X /Int ( 2 ^Int ( 8 *Int ( #getFirstOneBit(X) /Int 8 ) ) ) ) +Bytes
#buf ( #getFirstOneBit(X) /Int 8, Y ) )
requires #rangeUInt(256, X) andBool 0 <=Int #getFirstOneBit(X)
andBool 0 <=Int Y andBool Y <Int 2 ^Int ( 8 *Int ( #getFirstOneBit(X) /Int 8 ) )
[simplification(42), concrete(X), preserves-definedness]

// 4. Buffer cropping
rule [buf-asWord-crop]:
#buf (W:Int , #asWord(B:Bytes)) => #range(B, lengthBytes(B) -Int W, W)
requires 0 <=Int W andBool W <=Int 32 andBool W <Int lengthBytes(B)
andBool #asWord ( #range(B, 0, lengthBytes(B) -Int W) ) ==Int 0
[simplification, concrete(W), preserves-definedness]

// 3c. Splitting the updated buffer into the updated value and the trailing zeros, explicit shift
rule [buf-split-l]:
// 5. Splitting the updated buffer into the updated value and the trailing zeros
rule [buf-split-on-shift]:
#buf ( W, SHIFT *Int X ) => #buf( W -Int ( log2Int(SHIFT) /Int 8 ), X ) +Bytes #buf( log2Int(SHIFT) /Int 8, 0)
requires 0 <=Int W andBool W <=Int 32 andBool #isByteShift(SHIFT)
andBool 0 <=Int X andBool X <Int 2 ^Int (8 *Int (W -Int ( log2Int(SHIFT) /Int 8)))
[simplification, concrete(W, SHIFT), preserves-definedness]

// 3d. Splitting the updated buffer into the updated value and the trailing zeros, implicit shift
rule [bor-split]:
X |Int Y => #asWord ( #buf ( 32 -Int #getFirstOneBit(X) /Int 8, X /Int ( 2 ^Int ( 8 *Int ( #getFirstOneBit(X) /Int 8 ) ) ) ) +Bytes
#buf ( #getFirstOneBit(X) /Int 8, Y ) )
requires #rangeUInt(256, X) andBool 0 <=Int #getFirstOneBit(X)
andBool 0 <=Int Y andBool Y <Int 2 ^Int ( 8 *Int ( #getFirstOneBit(X) /Int 8 ) )
[simplification, concrete(X), preserves-definedness]

endmodule
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