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SubjectRe: [BUG] x86 kenel won't boot under Virtual PC
Linus Torvalds wrote:
>
> Peter - does gcc actually use NOPL in _32-bit_ code too? It really seems
> to be a stupid decision to make a binary not run on other CPU's over
> something as trivial as that. That's something I'd expect out of an Intel
> compiler just to mess with AMD, not out of gcc.
>

Yes, it does:

/* We need to decide which NOP sequence to use for 32bit and
64bit. When -mtune= is used:

1. For PROCESSOR_I386, PROCESSOR_I486, PROCESSOR_PENTIUM and
PROCESSOR_GENERIC32, f32_patt will be used.
2. For PROCESSOR_PENTIUMPRO, PROCESSOR_PENTIUM4, PROCESSOR_NOCONA,
PROCESSOR_CORE, PROCESSOR_CORE2, and PROCESSOR_GENERIC64,
alt_long_patt will be used.
3. For PROCESSOR_ATHLON, PROCESSOR_K6, PROCESSOR_K8 and
PROCESSOR_AMDFAM10, alt_short_patt will be used.

When -mtune= isn't used, alt_long_patt will be used if
cpu_arch_isa_flags has Cpu686. Otherwise, f32_patt will
be used.

"alt_long_patt" uses NOPL and its variants.

-hpa


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