mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
27 lines
486 B
Python
27 lines
486 B
Python
from rule import Rule
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from opcodes import *
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"""
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Rule:
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AND(A, SIGNEXTEND(B, X)) -> AND(A, X)
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given
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B < WordSize / 8 - 1 AND
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A & (1 << ((B + 1) * 8) - 1) == A
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"""
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n_bits = 128
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# Input vars
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X = BitVec('X', n_bits)
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A = BitVec('A', n_bits)
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B = BitVec('B', n_bits)
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rule = Rule()
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# Requirements
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rule.require(ULT(B, BitVecVal(n_bits // 8 - 1, n_bits)))
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rule.require((A & ((BitVecVal(1, n_bits) << ((B + 1) * 8)) - 1)) == A)
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rule.check(
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AND(A, SIGNEXTEND(B, X)),
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AND(A, X)
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)
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