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
|
||
|
|
from opcodes import *
|
||
|
|
|
||
|
|
"""
|
||
|
|
Rule:
|
||
|
|
AND(A, SIGNEXTEND(B, X)) -> AND(A, X)
|
||
|
|
given
|
||
|
|
B < WordSize / 8 - 1 AND
|
||
|
|
A & (1 << ((B + 1) * 8) - 1) == A
|
||
|
|
"""
|
||
|
|
|
||
|
|
n_bits = 128
|
||
|
|
|
||
|
|
# Input vars
|
||
|
|
X = BitVec('X', n_bits)
|
||
|
|
A = BitVec('A', n_bits)
|
||
|
|
B = BitVec('B', n_bits)
|
||
|
|
|
||
|
|
rule = Rule()
|
||
|
|
# Requirements
|
||
|
|
rule.require(ULT(B, BitVecVal(n_bits // 8 - 1, n_bits)))
|
||
|
|
rule.require((A & ((BitVecVal(1, n_bits) << ((B + 1) * 8)) - 1)) == A)
|
||
|
|
rule.check(
|
||
|
|
AND(A, SIGNEXTEND(B, X)),
|
||
|
|
AND(A, X)
|
||
|
|
)
|