[LLVMdev] X86 disassembler 0x66 prefix

[Olivier Meurant]

There is a problem on X86 disassembler for instructions beginning with x86
prefix :

$ echo "0x66 0x0f 0x6f 0x8f 0x00 0x00 0x00 0x00" | llvm-mc --disassemble
        movdqa  (%edi), %xmm1

$ echo "0x53 0x66 0x0f 0x6f 0x8f 0x00 0x00 0x00 0x00" | llvm-mc
--disassemble
        pushl   %ebx
<stdin>:1:6: warning: invalid instruction encoding
0x53 0x66 0x0f 0x6f 0x8f 0x00 0x00 0x00 0x00
     ^


I attach a patch, but I'm not really familiar with this code, so if someone
can review/correct, it would be great.

The problem is between readPrefixes and getId : prefixLocation depends on
buffer position, but necessaryPrefixLocation is never updated to match
buffer position.

Cheers,
Olivier.
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