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| author | Kevin Ryde <user42@zip.com.au> | 2001-08-24 01:36:50 +0200 |
|---|---|---|
| committer | Kevin Ryde <user42@zip.com.au> | 2001-08-24 01:36:50 +0200 |
| commit | 26028cd1287f3d9051dea54ee37d44b51f2666e7 (patch) | |
| tree | a623946a5e035391a35f96b5b412ef07bcd89dc7 /tune | |
| parent | e6b9e2463ba4b0e973bb0fe214fd5ab86803140c (diff) | |
| download | gmp-26028cd1287f3d9051dea54ee37d44b51f2666e7.tar.gz | |
* tune/speed.h (speed_cyclecounter) [x86]: Don't clobber ebx in PIC.
Diffstat (limited to 'tune')
| -rw-r--r-- | tune/speed.h | 40 |
1 files changed, 32 insertions, 8 deletions
diff --git a/tune/speed.h b/tune/speed.h index ad247e210..22b381785 100644 --- a/tune/speed.h +++ b/tune/speed.h @@ -258,16 +258,40 @@ double speed_umul_ppmm _PROTO ((struct speed_params *s)); /* low 32-bits in p[0], high 32-bits in p[1] */ void speed_cyclecounter _PROTO ((unsigned p[2])); -#if defined(__GNUC__) && ! defined (NO_ASM) \ +/* In i386 gcc -fPIC, ebx is a fixed register and can't be declared a dummy + output or a clobber for the cpuid, hence an explicit save and restore. A + clobber as such doesn't provoke an error unfortunately (gcc 3.0), so use + the dummy output style in non-PIC, so there's an error if somehow -fPIC + is used without a -DPIC to tell us about it. */ +#if defined(__GNUC__) && ! defined (NO_ASM) \ && (defined (__i386__) || defined (__i486__)) -#define speed_cyclecounter(p) \ - do { \ - __asm__ __volatile__ ("cpuid\n" \ - "rdtsc" \ - : "=a" ((p)[0]), "=d" ((p)[1]) \ - : \ - : "ebx", "ecx"); \ +#ifdef PIC +#define speed_cyclecounter(p) \ + do { \ + int __speed_cyclecounter__save_ebx; \ + int __speed_cyclecounter__dummy; \ + __asm__ __volatile__ ("movl %%ebx, %1\n" \ + "cpuid\n" \ + "movl %1, %%ebx\n" \ + "rdtsc" \ + : "=a" ((p)[0]), \ + "=&rm" (__speed_cyclecounter__save_ebx), \ + "=c" (__speed_cyclecounter__dummy), \ + "=d" ((p)[1])); \ } while (0) +#else +#define speed_cyclecounter(p) \ + do { \ + int __speed_cyclecounter__dummy1; \ + int __speed_cyclecounter__dummy2; \ + __asm__ __volatile__ ("cpuid\n" \ + "rdtsc" \ + : "=a" ((p)[0]), \ + "=b" (__speed_cyclecounter__dummy1), \ + "=c" (__speed_cyclecounter__dummy2), \ + "=d" ((p)[1])); \ + } while (0) +#endif #endif double speed_cyclecounter_diff _PROTO ((const unsigned end[2], |