MIP-7: Extension Opcodes

MIPs
2

Disclaimer: I’m currently analyzing the JUMPDEST situation, and might propose a different approach to it (that there are reasons for the extension opcode to be JUMPDEST-analysis neutral).

This is more of an editorial suggestion to current approach:

In the Jumpdest Analysis section, the rule is too weak. In current form 0xEE605B would cause the 0x5B to be an invalid jump destination. I think it should read:

As for PUSH1 opcode, an immediate data byte following a 0xEE byte is skipped over during JUMPDEST analysis.

In particular:

  1. In 0xEE5B the 0x5B is not a valid jump destination
  2. In 0xEE605B the 0x5B is a valid jump destination
  3. In 0xEE615B5Bboth 0x5B’s are valid jump destinations etc.

For completeness: we’re unfortunate EIP-8024 is considered for Amsterdam, complicating things. If it goes in, 0xE6EE5B, 0xEEE65B (and similar) must be dealt with.