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-rw-r--r--sysdeps/powerpc/powerpc64/bits/atomic.h42
1 files changed, 19 insertions, 23 deletions
diff --git a/sysdeps/powerpc/powerpc64/bits/atomic.h b/sysdeps/powerpc/powerpc64/bits/atomic.h
index 16bb994601..1a20e3f0fd 100644
--- a/sysdeps/powerpc/powerpc64/bits/atomic.h
+++ b/sysdeps/powerpc/powerpc64/bits/atomic.h
@@ -18,44 +18,40 @@
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
-/*
- * The 32-bit exchange_bool is different on powerpc64 because the subf
- * does signed 64-bit arthmatic while the lwarx is 32-bit unsigned
- * (a load word and zero (high 32) form) load.
- * In powerpc64 register values are 64-bit by default, including oldval.
- * Net we need to extend sign word the result of lwarx to 64-bit so the
- * 64-bit subtract from gives the expected result and sets the condition
- * correctly.
- */
+/* The 32-bit exchange_bool is different on powerpc64 because the subf
+ does signed 64-bit arthmatic while the lwarx is 32-bit unsigned
+ (a load word and zero (high 32) form) load.
+ In powerpc64 register values are 64-bit by default, including oldval.
+ The value in old val unknown sign extension, lwarx loads the 32-bit
+ value as unsigned. So we explicitly clear the high 32 bits in oldval. */
# define __arch_compare_and_exchange_bool_32_acq(mem, newval, oldval) \
({ \
- unsigned int __tmp; \
- __asm __volatile ( \
- "1: lwarx %0,0,%1\n" \
- " extsw %0,%0\n" \
- " subf. %0,%2,%0\n" \
+ unsigned int __tmp, __tmp2; \
+ __asm __volatile (" clrldi %1,%1,32\n" \
+ "1: lwarx %0,0,%2\n" \
+ " subf. %0,%1,%0\n" \
" bne 2f\n" \
- " stwcx. %3,0,%1\n" \
+ " stwcx. %4,0,%2\n" \
" bne- 1b\n" \
"2: " __ARCH_ACQ_INSTR \
- : "=&r" (__tmp) \
- : "b" (mem), "r" (oldval), "r" (newval) \
+ : "=&r" (__tmp), "=r" (__tmp2) \
+ : "b" (mem), "1" (oldval), "r" (newval) \
: "cr0", "memory"); \
__tmp != 0; \
})
# define __arch_compare_and_exchange_bool_32_rel(mem, newval, oldval) \
({ \
- unsigned int __tmp; \
+ unsigned int __tmp, __tmp2; \
__asm __volatile (__ARCH_REL_INSTR "\n" \
- "1: lwarx %0,0,%1\n" \
- " extsw %0,%0\n" \
- " subf. %0,%2,%0\n" \
+ " clrldi %1,%1,32\n" \
+ "1: lwarx %0,0,%2\n" \
+ " subf. %0,%1,%0\n" \
" bne 2f\n" \
- " stwcx. %3,0,%1\n" \
+ " stwcx. %4,0,%2\n" \
" bne- 1b\n" \
"2: " \
- : "=&r" (__tmp) \
+ : "=&r" (__tmp), "=r" (__tmp2) \
: "b" (mem), "r" (oldval), "r" (newval) \
: "cr0", "memory"); \
__tmp != 0; \