Mesa (master): util/u_atomic: Add implementation of __sync_val_compare_and_swap_8

[Matt Turner]

Module: Mesa
Branch: master
Commit: 1bbe18087312e1b8ccdba6ca6dd8f1c9740a8454
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=1bbe18087312e1b8ccdba6ca6dd8f1c9740a8454

Author: Matt Turner <mattst88 at gmail.com>
Date:   Thu Sep 14 11:00:26 2017 -0700

util/u_atomic: Add implementation of __sync_val_compare_and_swap_8

Needed for 32-bit PowerPC.

Cc: "17.2" <mesa-stable at lists.freedesktop.org>
Fixes: a6a38a038bd ("util/u_atomic: provide 64bit atomics where
they're missing")
Reviewed-by: Emil Velikov <emil.velikov at collabora.com>

---

 src/util/u_atomic.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/util/u_atomic.c b/src/util/u_atomic.c
index 44b75fb0c0..b32527fe34 100644
--- a/src/util/u_atomic.c
+++ b/src/util/u_atomic.c
@@ -61,6 +61,20 @@ __sync_sub_and_fetch_8(uint64_t *ptr, uint64_t val)
 }
 
 WEAK uint64_t
+__sync_val_compare_and_swap_8(uint64_t *ptr, uint64_t oldval, uint64_t newval)
+{
+   uint64_t r;
+
+   pthread_mutex_lock(&sync_mutex);
+   r = *ptr;
+   if (*ptr == oldval)
+      *ptr = newval;
+   pthread_mutex_unlock(&sync_mutex);
+
+   return r;
+}
+
+WEAK uint64_t
 __atomic_fetch_add_8(uint64_t *ptr, uint64_t val, int memorder)
 {
    return __sync_add_and_fetch(ptr, val);