X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=rts%2FPrimOps.cmm;h=e17c6fb3f870b7b923c79570cfe45a087bd787ee;hp=701654af49db72e31c77995aecee9bdf3082e9a4;hb=e5c3b478b3cd1707cf122833822f44b2ac09b8e9;hpb=59977b6c7cc81777dc6f8266c68945d1ab691aec

diff --git a/rts/PrimOps.cmm b/rts/PrimOps.cmm
index 701654a..e17c6fb 100644
--- a/rts/PrimOps.cmm
+++ b/rts/PrimOps.cmm
@@ -212,6 +212,7 @@ stg_unsafeThawArrayzh
   }
 }
 
+
 /* -----------------------------------------------------------------------------
    MutVar primitives
    -------------------------------------------------------------------------- */
@@ -230,6 +231,25 @@ stg_newMutVarzh
     RET_P(mv);
 }
 
+stg_casMutVarzh
+ /* MutVar# s a -> a -> a -> State# s -> (# State#, Int#, a #) */
+{
+    W_ mv, old, new, h;
+
+    mv  = R1;
+    old = R2;
+    new = R3;
+
+    (h) = foreign "C" cas(mv + SIZEOF_StgHeader + OFFSET_StgMutVar_var,
+                          old, new) [];
+    if (h != old) {
+        RET_NP(1,h);
+    } else {
+        RET_NP(0,h);
+    }
+}
+
+
 stg_atomicModifyMutVarzh
 {
     W_ mv, f, z, x, y, r, h;