sysdeps/powerpc/sys/platform/ppc.h

   1 /* Facilities specific to the PowerPC architecture
   2    Copyright (C) 2012 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _SYS_PLATFORM_PPC_H
  20 #define _SYS_PLATFORM_PPC_H     1
  21
  22 #include <features.h>
  23 #include <stdint.h>
  24 #include <bits/ppc.h>
  25
  26 /* Read the Time Base Register.   */
  27 static inline uint64_t
  28 __ppc_get_timebase (void)
  29 {
  30 #if __GNUC_PREREQ (4, 8)
  31   return __builtin_ppc_get_timebase ();
  32 #else
  33 # ifdef __powerpc64__
  34   uint64_t __tb;
  35   /* "volatile" is necessary here, because the user expects this assembly
  36      isn't moved after an optimization.  */
  37   __asm__ volatile ("mfspr %0, 268" : "=r" (__tb));
  38   return __tb;
  39 # else  /* not __powerpc64__ */
  40   uint32_t __tbu, __tbl, __tmp; \
  41   __asm__ volatile ("0:\n\t"
  42                     "mftbu %0\n\t"
  43                     "mftbl %1\n\t"
  44                     "mftbu %2\n\t"
  45                     "cmpw %0, %2\n\t"
  46                     "bne- 0b"
  47                     : "=r" (__tbu), "=r" (__tbl), "=r" (__tmp));
  48   return (((uint64_t) __tbu << 32) | __tbl);
  49 # endif  /* not __powerpc64__ */
  50 #endif
  51 }
  52
  53 #endif  /* sys/platform/ppc.h */