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softfloat: Add float_cmask and constants

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Testing more than one class at a time is better done with masks.
This reduces the static branch count.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2020-09-23 15:00:13 -07:00
parent 9793c1e224
commit 134eda00e9
1 changed files with 23 additions and 7 deletions
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30
fpu/softfloat.c
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@ -469,6 +469,20 @@ typedef enum __attribute__ ((__packed__)) {
float_class_snan,
} FloatClass;
#define float_cmask(bit) (1u << (bit))
enum {
float_cmask_zero = float_cmask(float_class_zero),
float_cmask_normal = float_cmask(float_class_normal),
float_cmask_inf = float_cmask(float_class_inf),
float_cmask_qnan = float_cmask(float_class_qnan),
float_cmask_snan = float_cmask(float_class_snan),
float_cmask_infzero = float_cmask_zero | float_cmask_inf,
float_cmask_anynan = float_cmask_qnan | float_cmask_snan,
};
/* Simple helpers for checking if, or what kind of, NaN we have */
static inline __attribute__((unused)) bool is_nan(FloatClass c)
{
@ -1338,26 +1352,28 @@ bfloat16 QEMU_FLATTEN bfloat16_mul(bfloat16 a, bfloat16 b, float_status *status)
static FloatParts muladd_floats(FloatParts a, FloatParts b, FloatParts c,
int flags, float_status *s)
{
bool inf_zero = ((1 << a.cls) | (1 << b.cls)) ==
((1 << float_class_inf) | (1 << float_class_zero));
bool p_sign;
bool inf_zero, p_sign;
bool sign_flip = flags & float_muladd_negate_result;
FloatClass p_class;
uint64_t hi, lo;
int p_exp;
int ab_mask, abc_mask;
ab_mask = float_cmask(a.cls) | float_cmask(b.cls);
abc_mask = float_cmask(c.cls) | ab_mask;
inf_zero = ab_mask == float_cmask_infzero;
/* It is implementation-defined whether the cases of (0,inf,qnan)
* and (inf,0,qnan) raise InvalidOperation or not (and what QNaN
* they return if they do), so we have to hand this information
* off to the target-specific pick-a-NaN routine.
*/
if (is_nan(a.cls) || is_nan(b.cls) || is_nan(c.cls)) {
if (unlikely(abc_mask & float_cmask_anynan)) {
return pick_nan_muladd(a, b, c, inf_zero, s);
}
if (inf_zero) {
float_raise(float_flag_invalid, s);
s->float_exception_flags |= float_flag_invalid;
return parts_default_nan(s);
}
@ -1371,9 +1387,9 @@ static FloatParts muladd_floats(FloatParts a, FloatParts b, FloatParts c,
p_sign ^= 1;
}
if (a.cls == float_class_inf || b.cls == float_class_inf) {
if (ab_mask & float_cmask_inf) {
p_class = float_class_inf;
} else if (a.cls == float_class_zero || b.cls == float_class_zero) {
} else if (ab_mask & float_cmask_zero) {
p_class = float_class_zero;
} else {
p_class = float_class_normal;