llvm dev - Sep 2013 - [LLVMdev] bug in X86 disasm code?

hi,

i found this code in X86DisassemblerDecoder.h

#define EA_BASES_32BIT  \
  ENTRY(EAX)            \
  ENTRY(ECX)            \
  ENTRY(EDX)            \
  ENTRY(EBX)            \
  ENTRY(sib)            \
  ENTRY(EBP)            \
  ENTRY(ESI)            \
  ENTRY(EDI)            \
  ENTRY(R8D)            \
  ENTRY(R9D)            \
  ENTRY(R10D)           \
  ENTRY(R11D)           \
  ENTRY(R12D)           \
  ENTRY(R13D)           \
  ENTRY(R14D)           \
  ENTRY(R15D)


the ENTRY(sib) looks suspicious. that should be ENTRY(ESP), no?

thanks.
J
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The encoding where ESP as a base should be indicates that there's an
additonal byte (the SIB byte) following this byte. The ESP base will be
encoded in the SIB byte in this case.


On Thu, Sep 12, 2013 at 1:24 AM, Jun Koi <junkoi2004 at gmail.com> wrote:
> hi,
>
> i found this code in X86DisassemblerDecoder.h
>
> #define EA_BASES_32BIT  \
>   ENTRY(EAX)            \
>   ENTRY(ECX)            \
>   ENTRY(EDX)            \
>   ENTRY(EBX)            \
>   ENTRY(sib)            \
>   ENTRY(EBP)            \
>   ENTRY(ESI)            \
>   ENTRY(EDI)            \
>   ENTRY(R8D)            \
>   ENTRY(R9D)            \
>   ENTRY(R10D)           \
>   ENTRY(R11D)           \
>   ENTRY(R12D)           \
>   ENTRY(R13D)           \
>   ENTRY(R14D)           \
>   ENTRY(R15D)
>
>
> the ENTRY(sib) looks suspicious. that should be ENTRY(ESP), no?
>
> thanks.
> J
>


-- 
~Craig
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