softfloat: Add float*_maybe_silence_nan() functions

Add functions float*_maybe_silence_nan() which ensure that a
value is not a signaling NaN by turning it into a quiet NaN.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Nathan Froyd <froydnj@codesourcery.com>

diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h
index 8e6aceb55262758b22e83d2c4ca11b69ced5ce96..07468786f91ec087719724ad665d2782d5fe1738 100644 (file)
--- a/fpu/softfloat-specialize.h
+++ b/fpu/softfloat-specialize.h
@@ -101,6 +101,25 @@ int float32_is_signaling_nan( float32 a_ )
 #endif
 }
 
+/*----------------------------------------------------------------------------
+| Returns a quiet NaN if the single-precision floating point value `a' is a
+| signaling NaN; otherwise returns `a'.
+*----------------------------------------------------------------------------*/
+
+float32 float32_maybe_silence_nan( float32 a_ )
+{
+    if (float32_is_signaling_nan(a_)) {
+        uint32_t a = float32_val(a_);
+#if SNAN_BIT_IS_ONE
+        a &= ~(1 << 22);
+#else
+        a |= (1 << 22);
+#endif
+        return make_float32(a);
+    }
+    return a_;
+}
+
 /*----------------------------------------------------------------------------
 | Returns the result of converting the single-precision floating-point NaN
 | `a' to the canonical NaN format.  If `a' is a signaling NaN, the invalid
@@ -233,6 +252,25 @@ int float64_is_signaling_nan( float64 a_ )
 #endif
 }
 
+/*----------------------------------------------------------------------------
+| Returns a quiet NaN if the double-precision floating point value `a' is a
+| signaling NaN; otherwise returns `a'.
+*----------------------------------------------------------------------------*/
+
+float64 float64_maybe_silence_nan( float64 a_ )
+{
+    if (float64_is_signaling_nan(a_)) {
+        bits64 a = float64_val(a_);
+#if SNAN_BIT_IS_ONE
+        a &= ~LIT64( 0x0008000000000000 );
+#else
+        a |= LIT64( 0x0008000000000000 );
+#endif
+        return make_float64(a);
+    }
+    return a_;
+}
+
 /*----------------------------------------------------------------------------
 | Returns the result of converting the double-precision floating-point NaN
 | `a' to the canonical NaN format.  If `a' is a signaling NaN, the invalid

diff --git a/fpu/softfloat.h b/fpu/softfloat.h
index 9bece80d4da0579bc1d3154a3d1c56be84a5dcae..2e651e2605bb65bb823159ab0cd5dedb7c6849a3 100644 (file)
--- a/fpu/softfloat.h
+++ b/fpu/softfloat.h
@@ -287,6 +287,7 @@ int float32_compare( float32, float32 STATUS_PARAM );
 int float32_compare_quiet( float32, float32 STATUS_PARAM );
 int float32_is_nan( float32 );
 int float32_is_signaling_nan( float32 );
+float32 float32_maybe_silence_nan( float32 );
 float32 float32_scalbn( float32, int STATUS_PARAM );
 
 INLINE float32 float32_abs(float32 a)
@@ -364,6 +365,7 @@ int float64_compare( float64, float64 STATUS_PARAM );
 int float64_compare_quiet( float64, float64 STATUS_PARAM );
 int float64_is_nan( float64 a );
 int float64_is_signaling_nan( float64 );
+float64 float64_maybe_silence_nan( float64 );
 float64 float64_scalbn( float64, int STATUS_PARAM );
 
 INLINE float64 float64_abs(float64 a)