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From aaae1616a09d359b52e929f944ca0ceb4bb7f831 Mon Sep 17 00:00:00 2001
From: Paul Menzel <paulepanter@users.sourceforge.net>
Date: Sun, 14 Aug 2011 21:55:09 +0200
Subject: [PATCH 3/4] Revert "fixed:[ios] Add memory barriers to cas() assembly to ensure alignment of memory accesses."
This reverts commit 92bab651e2253d172879995b50985645b77fecd2.
The build (OpenEmbedded `angstrom-2010.x` for `MACHINE = "beagleboard") fails with the following error.
CPP Atomics.o
make[1]: Entering directory `/oe/build-angstrom-next/angstrom-dev/work/armv7a-angstrom-linux-gnueabi/xbmc-10.05-r11+gitr0+92bab651e2253d172879995b50985645b77fecd2/git/xbmc/windows'
CPP GUIMediaWindow.o
/tmp/ccrsywuV.s: Assembler messages:
/tmp/ccrsywuV.s:40: Error: garbage following instruction -- `dmb ish'
/tmp/ccrsywuV.s:48: Error: garbage following instruction -- `dmb ish'
make[1]: *** [Atomics.o] Error 1
make[1]: Leaving directory `/oe/build-angstrom-next/angstrom-dev/work/armv7a-angstrom-linux-gnueabi/xbmc-10.05-r11+gitr0+92bab651e2253d172879995b50985645b77fecd2/git/xbmc/threads'
make: *** [xbmc/threads/threads.a] Error 2
---
xbmc/threads/Atomics.cpp | 33 ++++++++++++++++-----------------
1 files changed, 16 insertions(+), 17 deletions(-)
diff --git a/xbmc/threads/Atomics.cpp b/xbmc/threads/Atomics.cpp
index 0a98a7e..0967eb2 100644
--- a/xbmc/threads/Atomics.cpp
+++ b/xbmc/threads/Atomics.cpp
@@ -49,23 +49,22 @@ long cas(volatile long *pAddr, long expectedVal, long swapVal)
#elif defined(__arm__)
long cas(volatile long* pAddr, long expectedVal, long swapVal)
{
- register long prev;
- asm volatile (
- "dmb ish \n" // Memory barrier. Make sure all memory accesses appearing before this complete before any that appear after
- "1: \n"
- "ldrex %0, [%1] \n" // Load the current value of *pAddr(%1) into prev (%0) and lock pAddr,
- "cmp %0, %2 \n" // Verify that the current value (%0) == old value (%2)
- "bne 2f \n" // Bail if the two values are not equal [not as expected]
- "strex r1, %3, [%1] \n"
- "cmp r1, #0 \n"
- "bne 1b \n"
- "dmb ish \n" // Memory barrier.
- "2: \n"
- : "=&r" (prev)
- : "r"(pAddr), "r"(expectedVal),"r"(swapVal)
- : "r1"
- );
- return prev;
+ return(__sync_val_compare_and_swap(pAddr, expectedVal, swapVal));
+// register long prev;
+// asm volatile (
+// "1: \n"
+// "ldrex %0, [%1] \n" /* Load the current value of *pAddr(%1) into prev (%0) and lock pAddr, */
+// "cmp %0, %2 \n" /* Verify that the current value (%0) == old value (%2) */
+// "bne 2f \n" /* Bail if the two values are not equal [not as expected] */
+// "strex r1, %3, [%1] \n"
+// "cmp r1, #0 \n"
+// "bne 1b \n"
+// "2: "
+// : "=&r" (prev)
+// : "r"(pAddr), "r"(expectedVal),"r"(swapVal)
+// : "r1"
+// );
+// return prev;
}
#elif defined(__mips__)
--
1.7.2.5
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