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simonlindholm / asm-differ

Assembly diff script
The Unlicense
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x86 mov instruction immediate stripped of hex prefix #160

Open 1superchip opened 3 months ago

1superchip commented 3 months ago

Hex immediates in the mov instruction can be stripped of the hex prefix 0x causing an error with finding the address immediate in process_reloc.

mov is included in instructions_with_address_immediates for I686.

Code that removes the hex prefix:

        addr = ""
        if mnemonic in arch.instructions_with_address_immediates:
            row, addr = split_off_address(row)
            # objdump prefixes addresses with 0x/-0x if they don't resolve to some
            # symbol + offset. Strip that.
            addr = addr.replace("0x", "")

decomp.me scratch: https://decomp.me/scratch/dA1P1

Relevant line of code: g_EnemyManagerDrawChain.arg = mgr;

objdump output:

  9a:   mov    %edx,0x1c
                        9c: dir32       ?g_EnemyManagerDrawChain@@3VChainElem@@A-0xee5ec

0x1c is an offset which the relocation should be applied to: mov %edx,?g_EnemyManagerDrawChain@@3VChainElem@@A-0xee5ec+0x1c