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authorPeter Maydell <peter.maydell@linaro.org>2011-03-11 08:12:25 +0000
committerAurelien Jarno <aurelien@aurel32.net>2011-04-03 17:19:38 +0200
commit274f1b041e0d550750cc6992092ad0197b2c5320 (patch)
tree122064602cf7e564f761314b4fa903ae39c83adf /fpu
parent79c18be7dfe660ab48f9f535e6cabd38c9f1d73b (diff)
softfloat: Add float*_min() and float*_max() functions
Add min and max operations to softfloat. This allows us to implement propagation of NaNs and handling of negative zero correctly (unlike the approach of having target helper routines return one of the operands based on the result of a comparison op). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Diffstat (limited to 'fpu')
-rw-r--r--fpu/softfloat.c49
-rw-r--r--fpu/softfloat.h4
2 files changed, 53 insertions, 0 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 08e4ae03d..03fb9487b 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -6057,6 +6057,55 @@ int float128_compare_quiet( float128 a, float128 b STATUS_PARAM )
return float128_compare_internal(a, b, 1 STATUS_VAR);
}
+/* min() and max() functions. These can't be implemented as
+ * 'compare and pick one input' because that would mishandle
+ * NaNs and +0 vs -0.
+ */
+#define MINMAX(s, nan_exp) \
+INLINE float ## s float ## s ## _minmax(float ## s a, float ## s b, \
+ int ismin STATUS_PARAM ) \
+{ \
+ flag aSign, bSign; \
+ uint ## s ## _t av, bv; \
+ a = float ## s ## _squash_input_denormal(a STATUS_VAR); \
+ b = float ## s ## _squash_input_denormal(b STATUS_VAR); \
+ if (float ## s ## _is_any_nan(a) || \
+ float ## s ## _is_any_nan(b)) { \
+ return propagateFloat ## s ## NaN(a, b STATUS_VAR); \
+ } \
+ aSign = extractFloat ## s ## Sign(a); \
+ bSign = extractFloat ## s ## Sign(b); \
+ av = float ## s ## _val(a); \
+ bv = float ## s ## _val(b); \
+ if (aSign != bSign) { \
+ if (ismin) { \
+ return aSign ? a : b; \
+ } else { \
+ return aSign ? b : a; \
+ } \
+ } else { \
+ if (ismin) { \
+ return (aSign ^ (av < bv)) ? a : b; \
+ } else { \
+ return (aSign ^ (av < bv)) ? b : a; \
+ } \
+ } \
+} \
+ \
+float ## s float ## s ## _min(float ## s a, float ## s b STATUS_PARAM) \
+{ \
+ return float ## s ## _minmax(a, b, 1 STATUS_VAR); \
+} \
+ \
+float ## s float ## s ## _max(float ## s a, float ## s b STATUS_PARAM) \
+{ \
+ return float ## s ## _minmax(a, b, 0 STATUS_VAR); \
+}
+
+MINMAX(32, 0xff)
+MINMAX(64, 0x7ff)
+
+
/* Multiply A by 2 raised to the power N. */
float32 float32_scalbn( float32 a, int n STATUS_PARAM )
{
diff --git a/fpu/softfloat.h b/fpu/softfloat.h
index 5d05fa5cf..90f425017 100644
--- a/fpu/softfloat.h
+++ b/fpu/softfloat.h
@@ -324,6 +324,8 @@ int float32_le_quiet( float32, float32 STATUS_PARAM );
int float32_lt_quiet( float32, float32 STATUS_PARAM );
int float32_compare( float32, float32 STATUS_PARAM );
int float32_compare_quiet( float32, float32 STATUS_PARAM );
+float32 float32_min(float32, float32 STATUS_PARAM);
+float32 float32_max(float32, float32 STATUS_PARAM);
int float32_is_quiet_nan( float32 );
int float32_is_signaling_nan( float32 );
float32 float32_maybe_silence_nan( float32 );
@@ -436,6 +438,8 @@ int float64_le_quiet( float64, float64 STATUS_PARAM );
int float64_lt_quiet( float64, float64 STATUS_PARAM );
int float64_compare( float64, float64 STATUS_PARAM );
int float64_compare_quiet( float64, float64 STATUS_PARAM );
+float64 float64_min(float64, float64 STATUS_PARAM);
+float64 float64_max(float64, float64 STATUS_PARAM);
int float64_is_quiet_nan( float64 a );
int float64_is_signaling_nan( float64 );
float64 float64_maybe_silence_nan( float64 );