freebsd: fix atomic ops implementations

Stole from

http://www.freebsd.org/cgi/cvsweb.cgi/ports/audio/pulseaudio/files/patch-src_pulsecore_atomic.h?rev=1.6

src/pulsecore/atomic.h

@@ -180,6 +180,110 @@ static inline pa_bool_t pa_atomic_ptr_cmpxchg(pa_atomic_ptr_t *a, void *old_p, v
     return r == old_p;
 }
 
+#elif defined(__FreeBSD__)
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+#include <sys/param.h>
+#include <machine/atomic.h>
+
+#if __FreeBSD_version < 600000
+#if defined(__i386__) || defined(__amd64__)
+#if defined(__amd64__)
+#define atomic_load_acq_64      atomic_load_acq_long
+#endif
+static inline u_int atomic_fetchadd_int(volatile u_int *p, u_int v) {
+    __asm __volatile(
+            "   " __XSTRING(MPLOCKED) "         "
+            "   xaddl   %0, %1 ;        "
+            "# atomic_fetchadd_int"
+            : "+r" (v),
+            "=m" (*p)
+            : "m" (*p));
+
+    return (v);
+}
+#elif defined(__sparc64__)
+#define atomic_load_acq_64      atomic_load_acq_long
+#define atomic_fetchadd_int     atomic_add_int
+#elif defined(__ia64__)
+#define atomic_load_acq_64      atomic_load_acq_long
+static inline uint32_t
+atomic_fetchadd_int(volatile uint32_t *p, uint32_t v) {
+    uint32_t value;
+
+    do {
+        value = *p;
+    } while (!atomic_cmpset_32(p, value, value + v));
+    return (value);
+}
+#endif
+#endif
+
+typedef struct pa_atomic {
+    volatile unsigned long value;
+} pa_atomic_t;
+
+#define PA_ATOMIC_INIT(v) { .value = (v) }
+
+static inline int pa_atomic_load(const pa_atomic_t *a) {
+    return (int) atomic_load_acq_int((unsigned int *) &a->value);
+}
+
+static inline void pa_atomic_store(pa_atomic_t *a, int i) {
+    atomic_store_rel_int((unsigned int *) &a->value, i);
+}
+
+static inline int pa_atomic_add(pa_atomic_t *a, int i) {
+    return atomic_fetchadd_int((unsigned int *) &a->value, i);
+}
+
+static inline int pa_atomic_sub(pa_atomic_t *a, int i) {
+    return atomic_fetchadd_int((unsigned int *) &a->value, -(i));
+}
+
+static inline int pa_atomic_inc(pa_atomic_t *a) {
+    return atomic_fetchadd_int((unsigned int *) &a->value, 1);
+}
+
+static inline int pa_atomic_dec(pa_atomic_t *a) {
+    return atomic_fetchadd_int((unsigned int *) &a->value, -1);
+}
+
+static inline int pa_atomic_cmpxchg(pa_atomic_t *a, int old_i, int new_i) {
+    return atomic_cmpset_int((unsigned int *) &a->value, old_i, new_i);
+}
+
+typedef struct pa_atomic_ptr {
+    volatile unsigned long value;
+} pa_atomic_ptr_t;
+
+#define PA_ATOMIC_PTR_INIT(v) { .value = (unsigned long) (v) }
+
+static inline void* pa_atomic_ptr_load(const pa_atomic_ptr_t *a) {
+#ifdef atomic_load_acq_64
+    return (void*) atomic_load_acq_ptr((unsigned long *) &a->value);
+#else
+    return (void*) atomic_load_acq_ptr((unsigned int *) &a->value);
+#endif
+}
+
+static inline void pa_atomic_ptr_store(pa_atomic_ptr_t *a, void *p) {
+#ifdef atomic_load_acq_64
+    atomic_store_rel_ptr(&a->value, (unsigned long) p);
+#else
+    atomic_store_rel_ptr((unsigned int *) &a->value, (unsigned int) p);
+#endif
+}
+
+static inline int pa_atomic_ptr_cmpxchg(pa_atomic_ptr_t *a, void *old_p, void* new_p) {
+#ifdef atomic_load_acq_64
+    return atomic_cmpset_ptr(&a->value, (unsigned long) old_p, (unsigned long) new_p);
+#else
+    return atomic_cmpset_ptr((unsigned int *) &a->value, (unsigned int) old_p, (unsigned int) new_p);
+#endif
+}
+
 #elif defined(__GNUC__) && (defined(__amd64__) || defined(__x86_64__))
 
 #warn "The native atomic operations implementation for AMD64 has not been tested thoroughly. libatomic_ops is known to not work properly on AMD64 and your gcc version is too old for the gcc-builtin atomic ops support. You have three options now: test the native atomic operations implementation for AMD64, fix libatomic_ops, or upgrade your GCC."