* Accessing dl_hwcap from libm
@ 2004-05-12 2:23 Steve Munroe
2004-05-12 3:12 ` Ulrich Drepper
0 siblings, 1 reply; 2+ messages in thread
From: Steve Munroe @ 2004-05-12 2:23 UTC (permalink / raw)
To: libc-hacker; +Cc: Mark Brown
For powerpc32 I can't assume that the fsqrt instruction is implemented.
Currently it is implemented on ALL PPC64 hardware. So I would
like to use the AT_HWCAP to detect this and conditionally use fsqrt.
Looking at i386/fpu/fesetround I see that dl_hwcap is used to check for
SSE.
if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
But when I try something similar on powerpc w_sqrt I get:
../sysdeps/powerpc/fpu/w_sqrtf.c:37: undefined reference to
`_rtld_global_ro'
It seems that fesetround (and similar functions) are included in libc,
not libm. So is it fundamental that access to dl_dwcap (_rtld_global_ro)
is restricted to libc, or can access be extended to libm?
Steven J. Munroe
Linux on Power Toolchain Architect
IBM Corporation, Linux Technology Center
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: Accessing dl_hwcap from libm
2004-05-12 2:23 Accessing dl_hwcap from libm Steve Munroe
@ 2004-05-12 3:12 ` Ulrich Drepper
0 siblings, 0 replies; 2+ messages in thread
From: Ulrich Drepper @ 2004-05-12 3:12 UTC (permalink / raw)
To: Steve Munroe; +Cc: libc-hacker
Steve Munroe wrote:
> So is it fundamental that access to dl_dwcap (_rtld_global_ro)
> is restricted to libc, or can access be extended to libm?
_rtld_global_ro is defined in ld.so and exported from there. If you
cannot use it something is wrong with ld.so, the way libm is built, or
your binutils.
--
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA â–
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2004-05-12 2:23 Accessing dl_hwcap from libm Steve Munroe
2004-05-12 3:12 ` Ulrich Drepper
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