softfloat: Implement floatx80_is_any_nan() and float128_is_any_nan()

Implement versions of float*_is_any_nan() for the floatx80 and
float128 types.

Acked-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@iki.fi>

fpu/softfloat.h

diff --git a/fpu/softfloat.h b/fpu/softfloat.h
index 15052cc..a6d0f16 100644
--- a/fpu/softfloat.h
+++ b/fpu/softfloat.h
@@ -489,6 +489,11 @@
     return (a.high & 0x7fff) == 0 && a.low == 0;
 }
 
+INLINE int floatx80_is_any_nan(floatx80 a)
+{
+    return ((a.high & 0x7fff) == 0x7fff) && (a.low<<1);
+}
+
 #endif
 
 #ifdef FLOAT128
@@ -556,6 +561,12 @@
     return (a.high & 0x7fffffffffffffffLL) == 0 && a.low == 0;
 }
 
+INLINE int float128_is_any_nan(float128 a)
+{
+    return ((a.high >> 48) & 0x7fff) == 0x7fff &&
+        ((a.low != 0) || ((a.high & 0xffffffffffffLL) != 0));
+}
+
 #endif
 
 #else /* CONFIG_SOFTFLOAT */