[Qemu-devel] [PATCH v3 02/10] softfloat: add NO_SIGNALING_NANS

[Max Filippov <jcmvbkbc@gmail.com>]

Architectures that don't have signaling NaNs can define
NO_SIGNALING_NANS, it will make float*_is_quiet_nan return 1 for any NaN
and float*_is_signaling_nan always return 0.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 fpu/softfloat-specialize.h |   67 ++++++++++++++++++++++++++++++++++++++++++++
 fpu/softfloat.h            |    5 +++
 2 files changed, 72 insertions(+), 0 deletions(-)

diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h
index 4902450..50b54b8 100644
--- a/fpu/softfloat-specialize.h
+++ b/fpu/softfloat-specialize.h
@@ -41,6 +41,13 @@ these four paragraphs for those parts of this code that are retained.
 #define SNAN_BIT_IS_ONE		0
 #endif
 
+#if defined(TARGET_XTENSA)
+/* Define for architectures which deviate from IEEE in not supporting
+ * signaling NaNs (so all NaNs are treated as quiet).
+ */
+#define NO_SIGNALING_NANS 1
+#endif
+
 /*----------------------------------------------------------------------------
 | The pattern for a default generated half-precision NaN.
 *----------------------------------------------------------------------------*/
@@ -127,6 +134,17 @@ typedef struct {
     uint64_t high, low;
 } commonNaNT;
 
+#ifdef NO_SIGNALING_NANS
+int float16_is_quiet_nan(float16 a_)
+{
+    return float16_is_any_nan(a_);
+}
+
+int float16_is_signaling_nan(float16 a_)
+{
+    return 0;
+}
+#else
 /*----------------------------------------------------------------------------
 | Returns 1 if the half-precision floating-point value `a' is a quiet
 | NaN; otherwise returns 0.
@@ -156,6 +174,7 @@ int float16_is_signaling_nan(float16 a_)
     return (((a >> 9) & 0x3F) == 0x3E) && (a & 0x1FF);
 #endif
 }
+#endif
 
 /*----------------------------------------------------------------------------
 | Returns a quiet NaN if the half-precision floating point value `a' is a
@@ -217,6 +236,17 @@ static float16 commonNaNToFloat16(commonNaNT a STATUS_PARAM)
     }
 }
 
+#ifdef NO_SIGNALING_NANS
+int float32_is_quiet_nan(float32 a_)
+{
+    return float32_is_any_nan(a_);
+}
+
+int float32_is_signaling_nan(float32 a_)
+{
+    return 0;
+}
+#else
 /*----------------------------------------------------------------------------
 | Returns 1 if the single-precision floating-point value `a' is a quiet
 | NaN; otherwise returns 0.
@@ -246,6 +276,7 @@ int float32_is_signaling_nan( float32 a_ )
     return ( ( ( a>>22 ) & 0x1FF ) == 0x1FE ) && ( a & 0x003FFFFF );
 #endif
 }
+#endif
 
 /*----------------------------------------------------------------------------
 | Returns a quiet NaN if the single-precision floating point value `a' is a
@@ -586,6 +617,17 @@ static float32 propagateFloat32MulAddNaN(float32 a, float32 b,
     }
 }
 
+#ifdef NO_SIGNALING_NANS
+int float64_is_quiet_nan(float64 a_)
+{
+    return float64_is_any_nan(a_);
+}
+
+int float64_is_signaling_nan(float64 a_)
+{
+    return 0;
+}
+#else
 /*----------------------------------------------------------------------------
 | Returns 1 if the double-precision floating-point value `a' is a quiet
 | NaN; otherwise returns 0.
@@ -619,6 +661,7 @@ int float64_is_signaling_nan( float64 a_ )
         && ( a & LIT64( 0x0007FFFFFFFFFFFF ) );
 #endif
 }
+#endif
 
 /*----------------------------------------------------------------------------
 | Returns a quiet NaN if the double-precision floating point value `a' is a
@@ -773,6 +816,17 @@ static float64 propagateFloat64MulAddNaN(float64 a, float64 b,
     }
 }
 
+#ifdef NO_SIGNALING_NANS
+int floatx80_is_quiet_nan(floatx80 a_)
+{
+    return floatx80_is_any_nan(a_);
+}
+
+int floatx80_is_signaling_nan(floatx80 a_)
+{
+    return 0;
+}
+#else
 /*----------------------------------------------------------------------------
 | Returns 1 if the extended double-precision floating-point value `a' is a
 | quiet NaN; otherwise returns 0. This slightly differs from the same
@@ -816,6 +870,7 @@ int floatx80_is_signaling_nan( floatx80 a )
         && ( a.low == aLow );
 #endif
 }
+#endif
 
 /*----------------------------------------------------------------------------
 | Returns a quiet NaN if the extended double-precision floating point value
@@ -929,6 +984,17 @@ static floatx80 propagateFloatx80NaN( floatx80 a, floatx80 b STATUS_PARAM)
     }
 }
 
+#ifdef NO_SIGNALING_NANS
+int float128_is_quiet_nan(float128 a_)
+{
+    return float128_is_any_nan(a_);
+}
+
+int float128_is_signaling_nan(float128 a_)
+{
+    return 0;
+}
+#else
 /*----------------------------------------------------------------------------
 | Returns 1 if the quadruple-precision floating-point value `a' is a quiet
 | NaN; otherwise returns 0.
@@ -964,6 +1030,7 @@ int float128_is_signaling_nan( float128 a )
         && ( a.low || ( a.high & LIT64( 0x00007FFFFFFFFFFF ) ) );
 #endif
 }
+#endif
 
 /*----------------------------------------------------------------------------
 | Returns a quiet NaN if the quadruple-precision floating point value `a' is
diff --git a/fpu/softfloat.h b/fpu/softfloat.h
index 2860ca0..d8999b3 100644
--- a/fpu/softfloat.h
+++ b/fpu/softfloat.h
@@ -251,6 +251,11 @@ int float16_is_quiet_nan( float16 );
 int float16_is_signaling_nan( float16 );
 float16 float16_maybe_silence_nan( float16 );
 
+INLINE int float16_is_any_nan(float16 a)
+{
+    return ((float16_val(a) & ~0x8000) > 0x7c00);
+}
+
 /*----------------------------------------------------------------------------
 | The pattern for a default generated half-precision NaN.
 *----------------------------------------------------------------------------*/
-- 
1.7.7.6