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author | Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com> | 2012-06-04 13:46:37 -0500 |
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committer | Ryan S. Arnold <rsa@linux.vnet.ibm.com> | 2012-06-04 13:46:37 -0500 |
commit | d9dc34cd569bcfe714fe8c708e58c028106e8b2e (patch) | |
tree | 82c7c02aab8419ffd869c72b1b5644b1dae6eb38 /sysdeps/powerpc/sys | |
parent | 06775cb82b8c8381ea0cc636a70ed9e7ca81b548 (diff) | |
download | glibc-d9dc34cd569bcfe714fe8c708e58c028106e8b2e.tar.gz glibc-d9dc34cd569bcfe714fe8c708e58c028106e8b2e.tar.xz glibc-d9dc34cd569bcfe714fe8c708e58c028106e8b2e.zip |
Manual for platform-specific features and new __ppc_get_timebase inline.
[BZ #13743] A new class of installed headers has been documented for low-level platform-specific functionality. PowerPC added the first instance with a function to provide time base register access (__ppc_get_timebase). This is required for applications that measure time at high frequencies with high precision that can't afford a syscall.
Diffstat (limited to 'sysdeps/powerpc/sys')
-rw-r--r-- | sysdeps/powerpc/sys/platform/ppc.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/sysdeps/powerpc/sys/platform/ppc.h b/sysdeps/powerpc/sys/platform/ppc.h new file mode 100644 index 0000000000..165652c7cc --- /dev/null +++ b/sysdeps/powerpc/sys/platform/ppc.h @@ -0,0 +1,47 @@ +/* Facilities specific to the PowerPC architecture + Copyright (C) 2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#ifndef _SYS_PLATFORM_PPC_H +#define _SYS_PLATFORM_PPC_H 1 + +#include <stdint.h> + +/* Read the Time Base Register. */ +static inline uint64_t +__ppc_get_timebase (void) +{ +#ifdef __powerpc64__ + uint64_t __tb; + /* "volatile" is necessary here, because the user expects this assembly + isn't moved after an optimization. */ + __asm__ volatile ("mfspr %0, 268" : "=r" (__tb)); + return __tb; +#else /* not __powerpc64__ */ + uint32_t __tbu, __tbl, __tmp; \ + __asm__ volatile ("0:\n\t" + "mftbu %0\n\t" + "mftbl %1\n\t" + "mftbu %2\n\t" + "cmpw %0, %2\n\t" + "bne- 0b" + : "=r" (__tbu), "=r" (__tbl), "=r" (__tmp)); + return (((uint64_t) __tbu << 32) | __tbl); +#endif /* not __powerpc64__ */ +} + +#endif /* sys/platform/ppc.h */ |