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authorAlex Bennée <alex.bennee@linaro.org>2017-12-05 12:36:01 +0000
committerAlex Bennée <alex.bennee@linaro.org>2018-02-21 10:21:41 +0000
commit89360067071b1844bf745682e18db7dde74cdb8d (patch)
tree1fc3ea9f970e2a18df96ca31bbf00da9e21cacf9 /fpu
parent0bfc9f195209593e91a98cf2233753f56a2e5c02 (diff)
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fpu/softfloat: re-factor minmax
Let's do the same re-factor treatment for minmax functions. I still use the MACRO trick to expand but now all the checking code is common. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'fpu')
-rw-r--r--fpu/softfloat.c227
1 files changed, 120 insertions, 107 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index a07b855..7a53c36 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -1663,6 +1663,126 @@ float64 uint16_to_float64(uint16_t a, float_status *status)
return uint64_to_float64(a, status);
}
+/* Float Min/Max */
+/* min() and max() functions. These can't be implemented as
+ * 'compare and pick one input' because that would mishandle
+ * NaNs and +0 vs -0.
+ *
+ * minnum() and maxnum() functions. These are similar to the min()
+ * and max() functions but if one of the arguments is a QNaN and
+ * the other is numerical then the numerical argument is returned.
+ * SNaNs will get quietened before being returned.
+ * minnum() and maxnum correspond to the IEEE 754-2008 minNum()
+ * and maxNum() operations. min() and max() are the typical min/max
+ * semantics provided by many CPUs which predate that specification.
+ *
+ * minnummag() and maxnummag() functions correspond to minNumMag()
+ * and minNumMag() from the IEEE-754 2008.
+ */
+static FloatParts minmax_floats(FloatParts a, FloatParts b, bool ismin,
+ bool ieee, bool ismag, float_status *s)
+{
+ if (unlikely(is_nan(a.cls) || is_nan(b.cls))) {
+ if (ieee) {
+ /* Takes two floating-point values `a' and `b', one of
+ * which is a NaN, and returns the appropriate NaN
+ * result. If either `a' or `b' is a signaling NaN,
+ * the invalid exception is raised.
+ */
+ if (is_snan(a.cls) || is_snan(b.cls)) {
+ return pick_nan(a, b, s);
+ } else if (is_nan(a.cls) && !is_nan(b.cls)) {
+ return b;
+ } else if (is_nan(b.cls) && !is_nan(a.cls)) {
+ return a;
+ }
+ }
+ return pick_nan(a, b, s);
+ } else {
+ int a_exp, b_exp;
+ bool a_sign, b_sign;
+
+ switch (a.cls) {
+ case float_class_normal:
+ a_exp = a.exp;
+ break;
+ case float_class_inf:
+ a_exp = INT_MAX;
+ break;
+ case float_class_zero:
+ a_exp = INT_MIN;
+ break;
+ default:
+ g_assert_not_reached();
+ break;
+ }
+ switch (b.cls) {
+ case float_class_normal:
+ b_exp = b.exp;
+ break;
+ case float_class_inf:
+ b_exp = INT_MAX;
+ break;
+ case float_class_zero:
+ b_exp = INT_MIN;
+ break;
+ default:
+ g_assert_not_reached();
+ break;
+ }
+
+ a_sign = a.sign;
+ b_sign = b.sign;
+ if (ismag) {
+ a_sign = b_sign = 0;
+ }
+
+ if (a_sign == b_sign) {
+ bool a_less = a_exp < b_exp;
+ if (a_exp == b_exp) {
+ a_less = a.frac < b.frac;
+ }
+ return a_sign ^ a_less ^ ismin ? b : a;
+ } else {
+ return a_sign ^ ismin ? b : a;
+ }
+ }
+}
+
+#define MINMAX(sz, name, ismin, isiee, ismag) \
+float ## sz float ## sz ## _ ## name(float ## sz a, float ## sz b, \
+ float_status *s) \
+{ \
+ FloatParts pa = float ## sz ## _unpack_canonical(a, s); \
+ FloatParts pb = float ## sz ## _unpack_canonical(b, s); \
+ FloatParts pr = minmax_floats(pa, pb, ismin, isiee, ismag, s); \
+ \
+ return float ## sz ## _round_pack_canonical(pr, s); \
+}
+
+MINMAX(16, min, true, false, false)
+MINMAX(16, minnum, true, true, false)
+MINMAX(16, minnummag, true, true, true)
+MINMAX(16, max, false, false, false)
+MINMAX(16, maxnum, false, true, false)
+MINMAX(16, maxnummag, false, true, true)
+
+MINMAX(32, min, true, false, false)
+MINMAX(32, minnum, true, true, false)
+MINMAX(32, minnummag, true, true, true)
+MINMAX(32, max, false, false, false)
+MINMAX(32, maxnum, false, true, false)
+MINMAX(32, maxnummag, false, true, true)
+
+MINMAX(64, min, true, false, false)
+MINMAX(64, minnum, true, true, false)
+MINMAX(64, minnummag, true, true, true)
+MINMAX(64, max, false, false, false)
+MINMAX(64, maxnum, false, true, false)
+MINMAX(64, maxnummag, false, true, true)
+
+#undef MINMAX
+
/* Multiply A by 2 raised to the power N. */
static FloatParts scalbn_decomposed(FloatParts a, int n, float_status *s)
{
@@ -6912,113 +7032,6 @@ int float128_compare_quiet(float128 a, float128 b, float_status *status)
return float128_compare_internal(a, b, 1, status);
}
-/* min() and max() functions. These can't be implemented as
- * 'compare and pick one input' because that would mishandle
- * NaNs and +0 vs -0.
- *
- * minnum() and maxnum() functions. These are similar to the min()
- * and max() functions but if one of the arguments is a QNaN and
- * the other is numerical then the numerical argument is returned.
- * minnum() and maxnum correspond to the IEEE 754-2008 minNum()
- * and maxNum() operations. min() and max() are the typical min/max
- * semantics provided by many CPUs which predate that specification.
- *
- * minnummag() and maxnummag() functions correspond to minNumMag()
- * and minNumMag() from the IEEE-754 2008.
- */
-#define MINMAX(s) \
-static inline float ## s float ## s ## _minmax(float ## s a, float ## s b, \
- int ismin, int isieee, \
- int ismag, \
- float_status *status) \
-{ \
- flag aSign, bSign; \
- uint ## s ## _t av, bv, aav, abv; \
- a = float ## s ## _squash_input_denormal(a, status); \
- b = float ## s ## _squash_input_denormal(b, status); \
- if (float ## s ## _is_any_nan(a) || \
- float ## s ## _is_any_nan(b)) { \
- if (isieee) { \
- if (float ## s ## _is_quiet_nan(a, status) && \
- !float ## s ##_is_any_nan(b)) { \
- return b; \
- } else if (float ## s ## _is_quiet_nan(b, status) && \
- !float ## s ## _is_any_nan(a)) { \
- return a; \
- } \
- } \
- return propagateFloat ## s ## NaN(a, b, status); \
- } \
- aSign = extractFloat ## s ## Sign(a); \
- bSign = extractFloat ## s ## Sign(b); \
- av = float ## s ## _val(a); \
- bv = float ## s ## _val(b); \
- if (ismag) { \
- aav = float ## s ## _abs(av); \
- abv = float ## s ## _abs(bv); \
- if (aav != abv) { \
- if (ismin) { \
- return (aav < abv) ? a : b; \
- } else { \
- return (aav < abv) ? b : a; \
- } \
- } \
- } \
- 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, \
- float_status *status) \
-{ \
- return float ## s ## _minmax(a, b, 1, 0, 0, status); \
-} \
- \
-float ## s float ## s ## _max(float ## s a, float ## s b, \
- float_status *status) \
-{ \
- return float ## s ## _minmax(a, b, 0, 0, 0, status); \
-} \
- \
-float ## s float ## s ## _minnum(float ## s a, float ## s b, \
- float_status *status) \
-{ \
- return float ## s ## _minmax(a, b, 1, 1, 0, status); \
-} \
- \
-float ## s float ## s ## _maxnum(float ## s a, float ## s b, \
- float_status *status) \
-{ \
- return float ## s ## _minmax(a, b, 0, 1, 0, status); \
-} \
- \
-float ## s float ## s ## _minnummag(float ## s a, float ## s b, \
- float_status *status) \
-{ \
- return float ## s ## _minmax(a, b, 1, 1, 1, status); \
-} \
- \
-float ## s float ## s ## _maxnummag(float ## s a, float ## s b, \
- float_status *status) \
-{ \
- return float ## s ## _minmax(a, b, 0, 1, 1, status); \
-}
-
-MINMAX(32)
-MINMAX(64)
-
-
floatx80 floatx80_scalbn(floatx80 a, int n, float_status *status)
{
flag aSign;