http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46598
--- Comment #16 from H.J. Lu <hjl.tools at gmail dot com> 2010-11-23 15:44:35
UTC ---
(In reply to comment #14)
> (In reply to comment #13)
> > They can use the new rdtsc builtin.
>
> In which GCC version will it appear ? will be cool if you can share a little
> example as well.
GCC 4.5 supports it:
[...@gnu-6 tmp]$ cat x.c
#include <x86intrin.h>
unsigned long long
foo ()
{
return __rdtsc ();
}
[...@gnu-6 tmp]$ gcc -O2 x.c -S
[...@gnu-6 tmp]$ cat x.s
.file "x.c"
.text
.p2align 4,,15
.globl foo
.type foo, @function
foo:
.LFB535:
.cfi_startproc
rdtsc
salq $32, %rdx
orq %rdx, %rax
ret
.cfi_endproc
.LFE535:
.size foo, .-foo
.ident "GCC: (GNU) 4.5.1 20100924 (Red Hat 4.5.1-4)"
.section .note.GNU-stack,"",@progbits
[...@gnu-6 tmp]$ gcc -O2 x.c -S -m32
[...@gnu-6 tmp]$ cat x.s
.file "x.c"
.text
.p2align 4,,15
.globl foo
.type foo, @function
foo:
pushl %ebp
movl %esp, %ebp
rdtsc
popl %ebp
ret
.size foo, .-foo
.ident "GCC: (GNU) 4.5.1 20100924 (Red Hat 4.5.1-4)"
.section .note.GNU-stack,"",@progbits
[...@gnu-6 tmp]$
