From a40aad8ff24bbbde283aa17ef375c8b0ccde5bbe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20=C3=96man?= <andreas@lonelycoder.com>
Date: Thu, 18 Oct 2012 11:04:10 +0200
Subject: [PATCH] Rewrite atomic.h to depend on gcc intrinsics only

---
 src/atomic.h | 87 ++--------------------------------------------------
 1 file changed, 3 insertions(+), 84 deletions(-)

diff --git a/src/atomic.h b/src/atomic.h
index a9e1485e..1c3efb73 100644
--- a/src/atomic.h
+++ b/src/atomic.h
@@ -16,16 +16,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef HTSATOMIC_H__
-#define HTSATOMIC_H__
-
-/**
- * Atomically add 'incr' to *ptr and return the previous value
- */
-
-
-
-#if defined(linux) && __GNUC__ >= 4 && __GNUC_MINOR__ >=3 
+#pragma once
 
 static inline int
 atomic_add(volatile int *ptr, int incr)
@@ -33,80 +24,8 @@ atomic_add(volatile int *ptr, int incr)
   return __sync_fetch_and_add(ptr, incr);
 }
 
-#elif defined(__i386__) || defined(__x86_64__)
 static inline int
-atomic_add(volatile int *ptr, int incr)
+atomic_exchange(volatile int *ptr, int new)
 {
-  int r;
-  asm volatile("lock; xaddl %0, %1" :
-	       "=r"(r), "=m"(*ptr) : "0" (incr), "m" (*ptr) : "memory");
-  return r;
+  return  __sync_lock_test_and_set(ptr, new);
 }
-#elif defined(WII)
-
-#include <ogc/machine/processor.h>
-
-static inline int
-atomic_add(volatile int *ptr, int incr)
-{
-  int r, level;
-
-  /*
-   * Last time i checked libogc's context switcher did not do the
-   * necessary operations to clear locks held by lwarx/stwcx.
-   * Thus we need to resort to other means
-   */
-
-  _CPU_ISR_Disable(level);
-
-  r = *ptr;
-  *ptr = *ptr + incr;
-
-  _CPU_ISR_Restore(level);
-
-  return r;
-}
-#elif defined(__ppc__) || defined(__PPC__)
-
-/* somewhat based on code from darwin gcc  */
-static inline int
-atomic_add (volatile int *ptr, int incr)
-{
-  int tmp, res;
-  asm volatile("0:\n"
-               "lwarx  %1,0,%2\n"
-               "add%I3 %0,%1,%3\n"
-               "stwcx. %0,0,%2\n"
-               "bne-   0b\n"
-               : "=&r"(tmp), "=&b"(res)
-               : "r" (ptr), "Ir"(incr)
-               : "cr0", "memory");
-  
-  return res;
-}
-
-#elif defined(__arm__) 
-
-static inline int 
-atomic_add(volatile int *ptr, int val)
-{
-  int a, b, c;
-
-  asm volatile(  "0:\n\t"
-		 "ldr %0, [%3]\n\t"
-		 "add %1, %0, %4\n\t"
-		 "swp %2, %1, [%3]\n\t"
-		 "cmp %0, %2\n\t"
-		 "swpne %1, %2, [%3]\n\t"
-		 "bne 0b"
-		 : "=&r" (a), "=&r" (b), "=&r" (c)
-		 : "r" (ptr), "r" (val)
-		 : "cc", "memory");
-  return a;
-}
-
-#else
-#error Missing atomic ops
-#endif
-
-#endif /* HTSATOMIC_H__ */