add overflow to mullw

diff --git a/openpower/isa/fixedarith.mdwn b/openpower/isa/fixedarith.mdwn
index 65425d2ef0241ad0cbc7e530009d53bbe9d2fdf5..4447bd80ff945f28ee106ea63e9479290c04f2c3 100644 (file)
--- a/openpower/isa/fixedarith.mdwn
+++ b/openpower/isa/fixedarith.mdwn
@@ -350,6 +350,8 @@ Pseudo-code:
 
     prod[0:63] <- MULS((RA)[32:63], (RB)[32:63])
     RT <- prod
+    overflow <- (prod[32:64] != 0x0000_0000) &
+                (prod[32:64] != 0xffff_ffff)
 
 Special Registers Altered: