Arun Sharma wrote:
+#ifdef __i386__
__asm__ __volatile__ ("pushl %%ebx; cpuid; popl %%ebx"
: "=a" (eax), "=c" (ecx)
: "0" (1)
: "dx");
+#elif defined __x86_64__
+ __asm__ __volatile__ ("pushq %%rbx; cpuid; popq %%rbx"
+ : "=a" (eax), "=c" (ecx)
+ : "0" (1)
+ : "dx");
+#endif
+
Does this mean the ebx-clobbering bug in gcc 3.4 also exists on x86-64
(except it clobbers rbx instead)?
I really hate to see this end up a permanent part of the tree...
perhaps we should add a Linux style cpuid() function:
static inline void cpuid(int op, int *eax, int *ebx, int *ecx, int *edx)
{
int ax, bx, cx, dx;
#if defined __i386__ || defined __x86_64__
__asm__("cpuid"
: "=a" (ax),
"=b" (bx),
"=c" (cx),
"=d" (dx)
: "0" (op));
#else
#error cpuid not defined on current architecture
#endif
if (eax) *eax = ax;
if (ebx) *ebx = bx;
if (ecx) *ecx = cx
if (edx) *edx = dx;
}
This should take care of the ebx clobbering bug while also resulting in
more shared code.
Just a thought.
Regards,
Anthony Liguori
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