[Qemu-devel] [PATCH 4/6] softfloat: Correctly handle NaNs in float16_to_float32()

[Peter Maydell]

Correctly handle NaNs in float16_to_float32(), by defining and
using a float16ToCommonNaN() function, as we do with the other formats.

Signed-off-by: Peter Maydell <address@hidden>
---
 fpu/softfloat-specialize.h |   17 +++++++++++++++++
 fpu/softfloat.c            |    4 +---
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h
index 4907484..af82359 100644
--- a/fpu/softfloat-specialize.h
+++ b/fpu/softfloat-specialize.h
@@ -116,6 +116,23 @@ float16 float16_maybe_silence_nan(float16 a)
 }
 
 /*----------------------------------------------------------------------------
+| Returns the result of converting the half-precision floating-point NaN
+| `a' to the canonical NaN format.  If `a' is a signaling NaN, the invalid
+| exception is raised.
+*----------------------------------------------------------------------------*/
+
+static commonNaNT float16ToCommonNaN( float16 a STATUS_PARAM )
+{
+    commonNaNT z;
+
+    if ( float16_is_signaling_nan( a ) ) float_raise( float_flag_invalid 
STATUS_VAR );
+    z.sign = a >> 15;
+    z.low = 0;
+    z.high = ((bits64) a)<<54;
+    return z;
+}
+
+/*----------------------------------------------------------------------------
 | Returns the result of converting the canonical NaN `a' to the half-
 | precision floating-point format.
 *----------------------------------------------------------------------------*/
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 4d51428..735db38 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -2733,9 +2733,7 @@ float32 float16_to_float32(float16 a, flag ieee 
STATUS_PARAM)
 
     if (aExp == 0x1f && ieee) {
         if (aSig) {
-            /* Make sure correct exceptions are raised.  */
-            float32ToCommonNaN(a STATUS_VAR);
-            aSig |= 0x200;
+            return commonNaNToFloat32(float16ToCommonNaN(a STATUS_VAR) 
STATUS_VAR);
         }
         return packFloat32(aSign, 0xff, aSig << 13);
     }
-- 
1.7.1