Re: [Qemu-trivial] [PATCH] qemu-timer: Don't use RDTSC on 386s and 486s

[Peter Maydell]

On 23 November 2012 15:17, Peter Maydell <address@hidden> wrote:
> On 23 November 2012 15:15, Paolo Bonzini <address@hidden> wrote:
>> You should at least test __i686__ too:
>>
>> $ gcc -m32 -dM -E -x c /dev/null |grep __i
>> #define __i686 1
>> #define __i686__ 1
>> #define __i386 1
>> #define __i386__ 1
>
> Yuck. I had assumed gcc would define everything from i386
> on up when building for later cores.

...and there's an enormous list of x86 cores too. This bites
us already -- if you use '-march=native' to get "best for my
cpu" then on a Core2, say, it will define __i386__ and __core2__
but not __i686__, so TCG won't use cmov :-(

Anybody got any good ideas for how to say "is this at least
a 586/686?" in a way that won't fail for any newly introduced
x86 core types?

-- PMM