softfloat: add float{x80,128}_maybe_silence_nan()

Add float{x80,128}_maybe_silence_nan() functions, they will be need by
propagateFloat{x80,128}NaN().
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

fpu/softfloat-specialize.h

@@ -479,6 +479,29 @@ int floatx80_is_signaling_nan( floatx80 a )
 #endif
 }
 
+/*----------------------------------------------------------------------------
+| Returns a quiet NaN if the extended double-precision floating point value
+| `a' is a signaling NaN; otherwise returns `a'.
+*----------------------------------------------------------------------------*/
+
+floatx80 floatx80_maybe_silence_nan( floatx80 a )
+{
+    if (floatx80_is_signaling_nan(a)) {
+#if SNAN_BIT_IS_ONE
+#  if defined(TARGET_MIPS)
+        a.low = floatx80_default_nan_low;
+        a.high = floatx80_default_nan_high;
+#  else
+#    error Rules for silencing a signaling NaN are target-specific
+#  endif
+#else
+        a.low |= LIT64( 0xC000000000000000 );
+        return a;
+#endif
+    }
+    return a;
+}
+
 /*----------------------------------------------------------------------------
 | Returns the result of converting the extended double-precision floating-
 | point NaN `a' to the canonical NaN format.  If `a' is a signaling NaN, the
@@ -611,6 +634,29 @@ int float128_is_signaling_nan( float128 a )
 #endif
 }
 
+/*----------------------------------------------------------------------------
+| Returns a quiet NaN if the quadruple-precision floating point value `a' is
+| a signaling NaN; otherwise returns `a'.
+*----------------------------------------------------------------------------*/
+
+float128 float128_maybe_silence_nan( float128 a )
+{
+    if (float128_is_signaling_nan(a)) {
+#if SNAN_BIT_IS_ONE
+#  if defined(TARGET_MIPS)
+        a.low = float128_default_nan_low;
+        a.high = float128_default_nan_high;
+#  else
+#    error Rules for silencing a signaling NaN are target-specific
+#  endif
+#else
+        a.high |= LIT64( 0x0000800000000000 );
+        return a;
+#endif
+    }
+    return a;
+}
+
 /*----------------------------------------------------------------------------
 | Returns the result of converting the quadruple-precision floating-point NaN
 | `a' to the canonical NaN format.  If `a' is a signaling NaN, the invalid

fpu/softfloat.h

@@ -439,6 +439,7 @@ int floatx80_le_quiet( floatx80, floatx80 STATUS_PARAM );
 int floatx80_lt_quiet( floatx80, floatx80 STATUS_PARAM );
 int floatx80_is_quiet_nan( floatx80 );
 int floatx80_is_signaling_nan( floatx80 );
+floatx80 floatx80_maybe_silence_nan( floatx80 );
 floatx80 floatx80_scalbn( floatx80, int STATUS_PARAM );
 
 INLINE floatx80 floatx80_abs(floatx80 a)
@@ -505,6 +506,7 @@ int float128_compare( float128, float128 STATUS_PARAM );
 int float128_compare_quiet( float128, float128 STATUS_PARAM );
 int float128_is_quiet_nan( float128 );
 int float128_is_signaling_nan( float128 );
+float128 float128_maybe_silence_nan( float128 );
 float128 float128_scalbn( float128, int STATUS_PARAM );
 
 INLINE float128 float128_abs(float128 a)