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93dceeb10e
add `memory' clobber; optimise for constant `val'. (atomic_add): Likewise. (test_and_set): Remove `volatile'; add `memory' clobber; be more like the original `test_and_set'. (compare_and_swap): Remove `volatile'; add `memory' clobber; optimise for constant `oldval'. (always_swap): Remove `volatile'; add `memory' clobber.
105 lines
2.5 KiB
C
105 lines
2.5 KiB
C
/* Low-level functions for atomic operations. PowerPC version.
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Copyright (C) 1997, 1998, 1999 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#ifndef _ATOMICITY_H
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#define _ATOMICITY_H 1
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#include <inttypes.h>
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#if BROKEN_PPC_ASM_CR0
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# define __ATOMICITY_INLINE /* nothing */
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#else
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# define __ATOMICITY_INLINE inline
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#endif
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static __ATOMICITY_INLINE int
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__attribute__ ((unused))
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exchange_and_add (volatile uint32_t *mem, int val)
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{
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int tmp, result;
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__asm__ ("\
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0: lwarx %0,0,%2
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add%I3 %1,%0,%3
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stwcx. %1,0,%2
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bne- 0b
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" : "=&b"(result), "=&r"(tmp) : "r" (mem), "Ir"(val) : "cr0", "memory");
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return result;
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}
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static __ATOMICITY_INLINE void
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__attribute__ ((unused))
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atomic_add (volatile uint32_t *mem, int val)
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{
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int tmp;
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__asm__ ("\
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0: lwarx %0,0,%1
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add%I2 %0,%0,%2
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stwcx. %0,0,%1
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bne- 0b
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" : "=&b"(tmp) : "r" (mem), "Ir"(val) : "cr0", "memory");
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}
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static __ATOMICITY_INLINE int
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__attribute__ ((unused))
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compare_and_swap (volatile long int *p, long int oldval, long int newval)
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{
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int result;
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__asm__ ("\
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0: lwarx %0,0,%1
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sub%I2c. %0,%0,%2
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cntlzw %0,%0
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bne- 1f
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stwcx. %3,0,%1
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bne- 0b
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1:
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" : "=&b"(result) : "r"(p), "Ir"(oldval), "r"(newval) : "cr0", "memory");
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return result >> 5;
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}
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static __ATOMICITY_INLINE long int
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__attribute__ ((unused))
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always_swap (volatile long int *p, long int newval)
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{
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long int result;
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__asm__ ("\
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0: lwarx %0,0,%1
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stwcx. %2,0,%1
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bne- 0b
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" : "=&r"(result) : "r"(p), "r"(newval) : "cr0", "memory");
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return result;
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}
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static __ATOMICITY_INLINE int
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__attribute__ ((unused))
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test_and_set (volatile long int *p, long int newval)
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{
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int result;
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__asm__ ("\
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0: lwarx %0,0,%1
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cmpwi %0,0
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bne- 1f
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stwcx. %2,0,%1
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bne- 0b
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1:
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" : "=&r"(result) : "r"(p), "r"(newval) : "cr0", "memory");
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return result;
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}
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#endif /* atomicity.h */
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