From 0e47171f2fc20c3d93410ae5828033658154fd6a Mon Sep 17 00:00:00 2001
From: Geoff Keating <geoffk@cygnus.com>
Date: Thu, 17 May 2001 19:47:46 +0000
Subject: [PATCH] * sysdeps/powerpc/pt-machine.h
(HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS): Define.
(__compare_and_swap): Remove memory barriers.
(__compare_and_swap_with_release_semantics): New function.
2001-05-09 Geoff Keating <geoffk@redhat.com>
* sysdeps/powerpc/pt-machine.h
(HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS): Define.
(__compare_and_swap): Remove memory barriers.
(__compare_and_swap_with_release_semantics): New function.
---
linuxthreads/ChangeLog | 7 +++++
linuxthreads/sysdeps/powerpc/pt-machine.h | 36 +++++++++++++++++------
2 files changed, 34 insertions(+), 9 deletions(-)
diff --git a/linuxthreads/ChangeLog b/linuxthreads/ChangeLog
index 371bd4b8f5..d746ee31dd 100644
--- a/linuxthreads/ChangeLog
+++ b/linuxthreads/ChangeLog
@@ -1,3 +1,10 @@
+2001-05-09 Geoff Keating <geoffk@redhat.com>
+
+ * sysdeps/powerpc/pt-machine.h
+ (HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS): Define.
+ (__compare_and_swap): Remove memory barriers.
+ (__compare_and_swap_with_release_semantics): New function.
+
2001-04-24 Andreas Jaeger <aj@suse.de>
* wrapsyscall.c: send* and recv* return ssize_t.
diff --git a/linuxthreads/sysdeps/powerpc/pt-machine.h b/linuxthreads/sysdeps/powerpc/pt-machine.h
index 39defcd00f..5a684e9b13 100644
--- a/linuxthreads/sysdeps/powerpc/pt-machine.h
+++ b/linuxthreads/sysdeps/powerpc/pt-machine.h
@@ -1,6 +1,6 @@
/* Machine-dependent pthreads configuration and inline functions.
powerpc version.
- Copyright (C) 1996, 1997, 1998, 2000 Free Software Foundation, Inc.
+ Copyright (C) 1996, 1997, 1998, 2000, 2001 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
@@ -38,19 +38,38 @@ register char * stack_pointer __asm__ ("r1");
/* Compare-and-swap for semaphores. */
/* note that test-and-set(x) is the same as !compare-and-swap(x, 0, 1) */
-#define HAS_COMPARE_AND_SWAP
+#define HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS
#define IMPLEMENT_TAS_WITH_CAS
-#if BROKEN_PPC_ASM_CR0
-static
-#else
-PT_EI
-#endif
-int
+PT_EI int
__compare_and_swap (long int *p, long int oldval, long int newval)
{
int ret;
+ __asm__ __volatile__ (
+ "0: lwarx %0,0,%1 ;"
+ " xor. %0,%3,%0;"
+ " bne 1f;"
+ " stwcx. %2,0,%1;"
+ " bne- 0b;"
+ "1: "
+ : "=&r"(ret)
+ : "r"(p), "r"(newval), "r"(oldval)
+ : "cr0", "memory");
+ /* This version of __compare_and_swap is to be used when acquiring
+ a lock, so we don't need to worry about whether other memory
+ operations have completed, but we do need to be sure that any loads
+ after this point really occur after we have acquired the lock. */
+ __asm__ __volatile__ ("isync" : : : "memory");
+ return ret == 0;
+}
+
+PT_EI int
+__compare_and_swap_with_release_semantics (long int *p,
+ long int oldval, long int newval)
+{
+ int ret;
+
MEMORY_BARRIER ();
__asm__ __volatile__ (
"0: lwarx %0,0,%1 ;"
@@ -62,6 +81,5 @@ __compare_and_swap (long int *p, long int oldval, long int newval)
: "=&r"(ret)
: "r"(p), "r"(newval), "r"(oldval)
: "cr0", "memory");
- MEMORY_BARRIER ();
return ret == 0;
}