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fix(bitvec): return 0 for concrete ADDMOD/MULMOD with a zero modulus - #598
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mayuriphad wants to merge 2 commits into
Open
mayuriphad wants to merge 2 commits into
mayuriphad wants to merge 2 commits into
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Signed-off-by: mayuriphad <mayuriphad656@gmail.com>
Signed-off-by: mayuriphad <mayuriphad656@gmail.com>
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The EVM defines
ADDMODandMULMODwith a zero modulus as 0. The fully concrete fast path inHalmosBitVec.addmodandHalmosBitVec.mulmodcomputed(a + b) % modulus.valuedirectly, so a zero modulus raisedZeroDivisionErrorand aborted execution. The symbolic path already goes throughmod, which returns 0.Both fast paths now return 0 when the modulus is 0. The bytecode
6000600260030800(PUSH1 0, PUSH1 2, PUSH1 3, ADDMOD, STOP) from the issue now finishes, and the same holds forMULMOD.Fixes #595
Added concrete
addmod/mulmodcases totests/test_bitvec.pythat fail withZeroDivisionErrorwithout the change.