mirror of https://gitee.com/openkylin/qemu.git
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>
This commit is contained in:
Alex Bennée
parent
0bfc9f1952
commit
8936006707
227
fpu/softfloat.c
227
fpu/softfloat.c
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@ -1663,6 +1663,126 @@ float64 uint16_to_float64(uint16_t a, float_status *status)
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return uint64_to_float64(a, status);
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}
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/* Float Min/Max */
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/* min() and max() functions. These can't be implemented as
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* 'compare and pick one input' because that would mishandle
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* NaNs and +0 vs -0.
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*
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* minnum() and maxnum() functions. These are similar to the min()
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* and max() functions but if one of the arguments is a QNaN and
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* the other is numerical then the numerical argument is returned.
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* SNaNs will get quietened before being returned.
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* minnum() and maxnum correspond to the IEEE 754-2008 minNum()
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* and maxNum() operations. min() and max() are the typical min/max
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* semantics provided by many CPUs which predate that specification.
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*
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* minnummag() and maxnummag() functions correspond to minNumMag()
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* and minNumMag() from the IEEE-754 2008.
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*/
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static FloatParts minmax_floats(FloatParts a, FloatParts b, bool ismin,
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bool ieee, bool ismag, float_status *s)
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{
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if (unlikely(is_nan(a.cls) || is_nan(b.cls))) {
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if (ieee) {
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/* Takes two floating-point values `a' and `b', one of
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* which is a NaN, and returns the appropriate NaN
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* result. If either `a' or `b' is a signaling NaN,
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* the invalid exception is raised.
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*/
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if (is_snan(a.cls) || is_snan(b.cls)) {
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return pick_nan(a, b, s);
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} else if (is_nan(a.cls) && !is_nan(b.cls)) {
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return b;
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} else if (is_nan(b.cls) && !is_nan(a.cls)) {
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return a;
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}
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}
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return pick_nan(a, b, s);
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} else {
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int a_exp, b_exp;
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bool a_sign, b_sign;
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switch (a.cls) {
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case float_class_normal:
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a_exp = a.exp;
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break;
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case float_class_inf:
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a_exp = INT_MAX;
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break;
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case float_class_zero:
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a_exp = INT_MIN;
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break;
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default:
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g_assert_not_reached();
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break;
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}
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switch (b.cls) {
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case float_class_normal:
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b_exp = b.exp;
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break;
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case float_class_inf:
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b_exp = INT_MAX;
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break;
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case float_class_zero:
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b_exp = INT_MIN;
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break;
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default:
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g_assert_not_reached();
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break;
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}
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a_sign = a.sign;
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b_sign = b.sign;
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if (ismag) {
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a_sign = b_sign = 0;
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}
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if (a_sign == b_sign) {
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bool a_less = a_exp < b_exp;
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if (a_exp == b_exp) {
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a_less = a.frac < b.frac;
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}
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return a_sign ^ a_less ^ ismin ? b : a;
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} else {
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return a_sign ^ ismin ? b : a;
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}
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}
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}
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#define MINMAX(sz, name, ismin, isiee, ismag) \
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float ## sz float ## sz ## _ ## name(float ## sz a, float ## sz b, \
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float_status *s) \
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{ \
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FloatParts pa = float ## sz ## _unpack_canonical(a, s); \
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FloatParts pb = float ## sz ## _unpack_canonical(b, s); \
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FloatParts pr = minmax_floats(pa, pb, ismin, isiee, ismag, s); \
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\
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return float ## sz ## _round_pack_canonical(pr, s); \
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}
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MINMAX(16, min, true, false, false)
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MINMAX(16, minnum, true, true, false)
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MINMAX(16, minnummag, true, true, true)
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MINMAX(16, max, false, false, false)
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MINMAX(16, maxnum, false, true, false)
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MINMAX(16, maxnummag, false, true, true)
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MINMAX(32, min, true, false, false)
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MINMAX(32, minnum, true, true, false)
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MINMAX(32, minnummag, true, true, true)
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MINMAX(32, max, false, false, false)
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MINMAX(32, maxnum, false, true, false)
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MINMAX(32, maxnummag, false, true, true)
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MINMAX(64, min, true, false, false)
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MINMAX(64, minnum, true, true, false)
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MINMAX(64, minnummag, true, true, true)
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MINMAX(64, max, false, false, false)
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MINMAX(64, maxnum, false, true, false)
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MINMAX(64, maxnummag, false, true, true)
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#undef MINMAX
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/* Multiply A by 2 raised to the power N. */
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static FloatParts scalbn_decomposed(FloatParts a, int n, float_status *s)
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{
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@ -6912,113 +7032,6 @@ int float128_compare_quiet(float128 a, float128 b, float_status *status)
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return float128_compare_internal(a, b, 1, status);
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}
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/* min() and max() functions. These can't be implemented as
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* 'compare and pick one input' because that would mishandle
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* NaNs and +0 vs -0.
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*
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* minnum() and maxnum() functions. These are similar to the min()
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* and max() functions but if one of the arguments is a QNaN and
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* the other is numerical then the numerical argument is returned.
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* minnum() and maxnum correspond to the IEEE 754-2008 minNum()
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* and maxNum() operations. min() and max() are the typical min/max
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* semantics provided by many CPUs which predate that specification.
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*
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* minnummag() and maxnummag() functions correspond to minNumMag()
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* and minNumMag() from the IEEE-754 2008.
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*/
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#define MINMAX(s) \
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static inline float ## s float ## s ## _minmax(float ## s a, float ## s b, \
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int ismin, int isieee, \
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int ismag, \
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float_status *status) \
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{ \
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flag aSign, bSign; \
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uint ## s ## _t av, bv, aav, abv; \
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a = float ## s ## _squash_input_denormal(a, status); \
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b = float ## s ## _squash_input_denormal(b, status); \
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if (float ## s ## _is_any_nan(a) || \
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float ## s ## _is_any_nan(b)) { \
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if (isieee) { \
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if (float ## s ## _is_quiet_nan(a, status) && \
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!float ## s ##_is_any_nan(b)) { \
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return b; \
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} else if (float ## s ## _is_quiet_nan(b, status) && \
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!float ## s ## _is_any_nan(a)) { \
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return a; \
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} \
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} \
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return propagateFloat ## s ## NaN(a, b, status); \
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} \
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aSign = extractFloat ## s ## Sign(a); \
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bSign = extractFloat ## s ## Sign(b); \
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av = float ## s ## _val(a); \
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bv = float ## s ## _val(b); \
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if (ismag) { \
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aav = float ## s ## _abs(av); \
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abv = float ## s ## _abs(bv); \
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if (aav != abv) { \
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if (ismin) { \
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return (aav < abv) ? a : b; \
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} else { \
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return (aav < abv) ? b : a; \
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} \
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} \
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} \
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if (aSign != bSign) { \
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if (ismin) { \
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return aSign ? a : b; \
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} else { \
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return aSign ? b : a; \
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} \
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} else { \
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if (ismin) { \
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return (aSign ^ (av < bv)) ? a : b; \
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} else { \
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return (aSign ^ (av < bv)) ? b : a; \
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} \
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} \
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} \
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\
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float ## s float ## s ## _min(float ## s a, float ## s b, \
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float_status *status) \
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{ \
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return float ## s ## _minmax(a, b, 1, 0, 0, status); \
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} \
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\
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float ## s float ## s ## _max(float ## s a, float ## s b, \
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float_status *status) \
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{ \
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return float ## s ## _minmax(a, b, 0, 0, 0, status); \
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} \
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\
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float ## s float ## s ## _minnum(float ## s a, float ## s b, \
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float_status *status) \
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{ \
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return float ## s ## _minmax(a, b, 1, 1, 0, status); \
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} \
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\
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float ## s float ## s ## _maxnum(float ## s a, float ## s b, \
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float_status *status) \
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{ \
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return float ## s ## _minmax(a, b, 0, 1, 0, status); \
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} \
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\
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float ## s float ## s ## _minnummag(float ## s a, float ## s b, \
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float_status *status) \
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{ \
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return float ## s ## _minmax(a, b, 1, 1, 1, status); \
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} \
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\
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float ## s float ## s ## _maxnummag(float ## s a, float ## s b, \
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float_status *status) \
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{ \
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return float ## s ## _minmax(a, b, 0, 1, 1, status); \
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}
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MINMAX(32)
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MINMAX(64)
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floatx80 floatx80_scalbn(floatx80 a, int n, float_status *status)
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{
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flag aSign;
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@ -245,6 +245,12 @@ float16 float16_mul(float16, float16, float_status *status);
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float16 float16_muladd(float16, float16, float16, int, float_status *status);
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float16 float16_div(float16, float16, float_status *status);
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float16 float16_scalbn(float16, int, float_status *status);
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float16 float16_min(float16, float16, float_status *status);
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float16 float16_max(float16, float16, float_status *status);
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float16 float16_minnum(float16, float16, float_status *status);
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float16 float16_maxnum(float16, float16, float_status *status);
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float16 float16_minnummag(float16, float16, float_status *status);
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float16 float16_maxnummag(float16, float16, float_status *status);
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int float16_is_quiet_nan(float16, float_status *status);
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int float16_is_signaling_nan(float16, float_status *status);
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