[Sbcl-devel] Patch: Disassembly of INC and DEC under x86-64

[<lut...@fr...>]

Hi,

there are still some glitches left in the x86-64 disassembler.
Here is a patch that improves the disassembly of the INC and DEC
instructions.

It replaces the instruction-format MODRM-REG-NO-WIDTH (that accidentally
works for some forms of these instructions) by REX-REG/MEM. This allows
to remove the former, simplifying the source code (and reducing the core
size), and improves the disassembly in the following cases:

- INC and DEC of byte registers needing a REX prefix
  Old:  40        BYTE #X40
        FEC6      INC DH
        41        BYTE #X41
        FEC7      INC BH
  New:  40FEC6    INC SIL
        41FEC7    INC R15B

- INC and DEC of a memory operand
  Old:  48FF45    INC RBP
        E8        out of sync
  New:  48FF45E8  INC QWORD PTR [RBP-24]

Yours

Lutz Euler