fix: clear dst1 to zero#110
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Before executing each opcode, zk_evm clears the decoded dst1 register and, after execution, leaves it at zero unless the instruction produced a second output (see zksync-protocol#222). vm2 previously left dst1 untouched, so an instruction with a "dirty" non-r0 dst1 field, or one that panics before writing dst1 (UMA read with increment), could leave dst1 in a different state than zk_evm. A panic caught by a near-call frame does not reset registers, so the divergence is observable. Mirror zk_evm's behavior: - Store the dst1 register for every opcode during decoding (it already fits in the destination register slot of Arguments). - Track whether the second output was written (Mul/Div and UMA reads with increment) via a transient State flag. - In full_boilerplate, after the business logic runs, clear dst1 to zero unless it was written. The clear happens after the primary output so that a dst0/dst1 alias resolves to zero, and after pre-execution panics have already returned, matching zk_evm's opcode masking. Bump the zk_evm pin to a commit that includes the matching reference fix, and add regression tests for the alias and UMA-increment-panic cases. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Change
Mirrors zk_evm's mechanism
zk_evm pin
Bumped zk_evm/zkevm_opcode_defs/zk_evm_abstractions to ac58f328 (v0.153.12)