[Qemu-devel] [PATCH 01/14] softfloat: implement fused multiply-add NaN propagation for MIPS

[Aurelien Jarno <aurelien@aurel32.net>]

Add a pickNaNMulAdd function for MIPS, implementing NaN propagation
rules for MIPS fused multiply-add instructions.

Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
---
 fpu/softfloat-specialize.h |   27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h
index a1d489e..518f694 100644
--- a/fpu/softfloat-specialize.h
+++ b/fpu/softfloat-specialize.h
@@ -486,6 +486,33 @@ static int pickNaNMulAdd(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
         return 1;
     }
 }
+#elif defined(TARGET_MIPS)
+static int pickNaNMulAdd(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
+                         flag cIsQNaN, flag cIsSNaN, flag infzero STATUS_PARAM)
+{
+    /* For MIPS, the (inf,zero,qnan) case sets InvalidOp and returns
+     * the default NaN
+     */
+    if (infzero) {
+        float_raise(float_flag_invalid STATUS_VAR);
+        return 3;
+    }
+
+    /* Prefer sNaN over qNaN, in the a, b, c order. */
+    if (aIsSNaN) {
+        return 0;
+    } else if (bIsSNaN) {
+        return 1;
+    } else if (cIsSNaN) {
+        return 2;
+    } else if (aIsQNaN) {
+        return 0;
+    } else if (bIsQNaN) {
+        return 1;
+    } else {
+        return 2;
+    }
+}
 #elif defined(TARGET_PPC)
 static int pickNaNMulAdd(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
                          flag cIsQNaN, flag cIsSNaN, flag infzero STATUS_PARAM)
-- 
1.7.10.4