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authorPeter Maydell <peter.maydell@linaro.org>2015-01-12 14:38:27 +0000
committerPeter Maydell <peter.maydell@linaro.org>2015-01-29 16:45:33 +0000
commit332d5849708d11b835e0b36f4e26e8b36bfb3f5a (patch)
tree022e3157f592ba233f8b7204a1e2c3638ac5c9d9 /fpu
parent6bb8e0f130bd4aecfe835a0caa94390fa2235fde (diff)
downloadqemu-arm-332d5849708d11b835e0b36f4e26e8b36bfb3f5a.tar.gz
softfloat: Revert and reimplement remaining parts of b645bb4885 and 5a6932d51d
Revert the parts of commits b645bb4885 and 5a6932d51d which are still in the codebase and under a SoftFloat-2b license. Reimplement support for architectures where the most significant bit in the mantissa is 1 for a signaling NaN rather than a quiet NaN, by adding handling for SNAN_BIT_IS_ONE being set to the functions which test values for NaN-ness. This includes restoring the bugfixes lost in the reversion where some of the float*_is_quiet_nan() functions were returning true for both signaling and quiet NaNs. [This is a mechanical squashing together of two separate "revert" and "reimplement" patches.] Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1421073508-23909-4-git-send-email-peter.maydell@linaro.org
Diffstat (limited to 'fpu')
-rw-r--r--fpu/softfloat-specialize.h57
1 files changed, 29 insertions, 28 deletions
diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h
index 39335b4d51..95e3647a43 100644
--- a/fpu/softfloat-specialize.h
+++ b/fpu/softfloat-specialize.h
@@ -33,10 +33,14 @@ this code that are retained.
===============================================================================
*/
+/* Does the target distinguish signaling NaNs from non-signaling NaNs
+ * by setting the most significant bit of the mantissa for a signaling NaN?
+ * (The more common choice is to have it be zero for SNaN and one for QNaN.)
+ */
#if defined(TARGET_MIPS) || defined(TARGET_SH4) || defined(TARGET_UNICORE32)
-#define SNAN_BIT_IS_ONE 1
+#define SNAN_BIT_IS_ONE 1
#else
-#define SNAN_BIT_IS_ONE 0
+#define SNAN_BIT_IS_ONE 0
#endif
#if defined(TARGET_XTENSA)
@@ -79,7 +83,7 @@ const float64 float64_default_nan = const_float64(LIT64( 0x7FFFFFFFFFFFFFFF ));
#elif defined(TARGET_PPC) || defined(TARGET_ARM) || defined(TARGET_ALPHA)
const float64 float64_default_nan = const_float64(LIT64( 0x7FF8000000000000 ));
#elif SNAN_BIT_IS_ONE
-const float64 float64_default_nan = const_float64(LIT64( 0x7FF7FFFFFFFFFFFF ));
+const float64 float64_default_nan = const_float64(LIT64(0x7FF7FFFFFFFFFFFF));
#else
const float64 float64_default_nan = const_float64(LIT64( 0xFFF8000000000000 ));
#endif
@@ -89,7 +93,7 @@ const float64 float64_default_nan = const_float64(LIT64( 0xFFF8000000000000 ));
*----------------------------------------------------------------------------*/
#if SNAN_BIT_IS_ONE
#define floatx80_default_nan_high 0x7FFF
-#define floatx80_default_nan_low LIT64( 0xBFFFFFFFFFFFFFFF )
+#define floatx80_default_nan_low LIT64(0xBFFFFFFFFFFFFFFF)
#else
#define floatx80_default_nan_high 0xFFFF
#define floatx80_default_nan_low LIT64( 0xC000000000000000 )
@@ -103,8 +107,8 @@ const floatx80 floatx80_default_nan
| `low' values hold the most- and least-significant bits, respectively.
*----------------------------------------------------------------------------*/
#if SNAN_BIT_IS_ONE
-#define float128_default_nan_high LIT64( 0x7FFF7FFFFFFFFFFF )
-#define float128_default_nan_low LIT64( 0xFFFFFFFFFFFFFFFF )
+#define float128_default_nan_high LIT64(0x7FFF7FFFFFFFFFFF)
+#define float128_default_nan_low LIT64(0xFFFFFFFFFFFFFFFF)
#else
#define float128_default_nan_high LIT64( 0xFFFF800000000000 )
#define float128_default_nan_low LIT64( 0x0000000000000000 )
@@ -255,9 +259,9 @@ int float32_is_quiet_nan( float32 a_ )
{
uint32_t a = float32_val(a_);
#if SNAN_BIT_IS_ONE
- return ( ( ( a>>22 ) & 0x1FF ) == 0x1FE ) && ( a & 0x003FFFFF );
+ return (((a >> 22) & 0x1ff) == 0x1fe) && (a & 0x003fffff);
#else
- return ( 0xFF800000 <= (uint32_t) ( a<<1 ) );
+ return ((uint32_t)(a << 1) >= 0xff800000);
#endif
}
@@ -270,7 +274,7 @@ int float32_is_signaling_nan( float32 a_ )
{
uint32_t a = float32_val(a_);
#if SNAN_BIT_IS_ONE
- return ( 0xFF800000 <= (uint32_t) ( a<<1 ) );
+ return ((uint32_t)(a << 1) >= 0xff800000);
#else
return ( ( ( a>>22 ) & 0x1FF ) == 0x1FE ) && ( a & 0x003FFFFF );
#endif
@@ -663,11 +667,10 @@ int float64_is_quiet_nan( float64 a_ )
{
uint64_t a = float64_val(a_);
#if SNAN_BIT_IS_ONE
- return
- ( ( ( a>>51 ) & 0xFFF ) == 0xFFE )
- && ( a & LIT64( 0x0007FFFFFFFFFFFF ) );
+ return (((a >> 51) & 0xfff) == 0xffe)
+ && (a & 0x0007ffffffffffffULL);
#else
- return ( LIT64( 0xFFF0000000000000 ) <= (uint64_t) ( a<<1 ) );
+ return ((a << 1) >= 0xfff0000000000000ULL);
#endif
}
@@ -680,7 +683,7 @@ int float64_is_signaling_nan( float64 a_ )
{
uint64_t a = float64_val(a_);
#if SNAN_BIT_IS_ONE
- return ( LIT64( 0xFFF0000000000000 ) <= (uint64_t) ( a<<1 ) );
+ return ((a << 1) >= 0xfff0000000000000ULL);
#else
return
( ( ( a>>51 ) & 0xFFF ) == 0xFFE )
@@ -864,11 +867,10 @@ int floatx80_is_quiet_nan( floatx80 a )
#if SNAN_BIT_IS_ONE
uint64_t aLow;
- aLow = a.low & ~ LIT64( 0x4000000000000000 );
- return
- ( ( a.high & 0x7FFF ) == 0x7FFF )
- && (uint64_t) ( aLow<<1 )
- && ( a.low == aLow );
+ aLow = a.low & ~0x4000000000000000ULL;
+ return ((a.high & 0x7fff) == 0x7fff)
+ && (aLow << 1)
+ && (a.low == aLow);
#else
return ( ( a.high & 0x7FFF ) == 0x7FFF )
&& (LIT64( 0x8000000000000000 ) <= ((uint64_t) ( a.low<<1 )));
@@ -884,8 +886,8 @@ int floatx80_is_quiet_nan( floatx80 a )
int floatx80_is_signaling_nan( floatx80 a )
{
#if SNAN_BIT_IS_ONE
- return ( ( a.high & 0x7FFF ) == 0x7FFF )
- && (LIT64( 0x8000000000000000 ) <= ((uint64_t) ( a.low<<1 )));
+ return ((a.high & 0x7fff) == 0x7fff)
+ && ((a.low << 1) >= 0x8000000000000000ULL);
#else
uint64_t aLow;
@@ -1029,13 +1031,12 @@ int float128_is_signaling_nan(float128 a_)
int float128_is_quiet_nan( float128 a )
{
#if SNAN_BIT_IS_ONE
- return
- ( ( ( a.high>>47 ) & 0xFFFF ) == 0xFFFE )
- && ( a.low || ( a.high & LIT64( 0x00007FFFFFFFFFFF ) ) );
+ return (((a.high >> 47) & 0xffff) == 0xfffe)
+ && (a.low || (a.high & 0x00007fffffffffffULL));
#else
return
- ( LIT64( 0xFFFE000000000000 ) <= (uint64_t) ( a.high<<1 ) )
- && ( a.low || ( a.high & LIT64( 0x0000FFFFFFFFFFFF ) ) );
+ ((a.high << 1) >= 0xffff000000000000ULL)
+ && (a.low || (a.high & 0x0000ffffffffffffULL));
#endif
}
@@ -1048,8 +1049,8 @@ int float128_is_signaling_nan( float128 a )
{
#if SNAN_BIT_IS_ONE
return
- ( LIT64( 0xFFFE000000000000 ) <= (uint64_t) ( a.high<<1 ) )
- && ( a.low || ( a.high & LIT64( 0x0000FFFFFFFFFFFF ) ) );
+ ((a.high << 1) >= 0xffff000000000000ULL)
+ && (a.low || (a.high & 0x0000ffffffffffffULL));
#else
return
( ( ( a.high>>47 ) & 0xFFFF ) == 0xFFFE )