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/*
* QEMU float support
*
* The code in this source file is derived from release 2a of the SoftFloat
* IEC/IEEE Floating-point Arithmetic Package. Those parts of the code (and
* some later contributions) are provided under that license, as detailed below.
* It has subsequently been modified by contributors to the QEMU Project,
* so some portions are provided under:
* the SoftFloat-2a license
* the BSD license
* GPL-v2-or-later
*
* Any future contributions to this file after December 1st 2014 will be
* taken to be licensed under the Softfloat-2a license unless specifically
* indicated otherwise.
*/
static void partsN(return_nan)(FloatPartsN *a, float_status *s)
{
switch (a->cls) {
case float_class_snan:
float_raise(float_flag_invalid, s);
if (s->default_nan_mode) {
parts_default_nan(a, s);
} else {
parts_silence_nan(a, s);
}
break;
case float_class_qnan:
if (s->default_nan_mode) {
parts_default_nan(a, s);
}
break;
default:
g_assert_not_reached();
}
}
static FloatPartsN *partsN(pick_nan)(FloatPartsN *a, FloatPartsN *b,
float_status *s)
{
if (is_snan(a->cls) || is_snan(b->cls)) {
float_raise(float_flag_invalid, s);
}
if (s->default_nan_mode) {
parts_default_nan(a, s);
} else {
int cmp = frac_cmp(a, b);
if (cmp == 0) {
cmp = a->sign < b->sign;
}
if (pickNaN(a->cls, b->cls, cmp > 0, s)) {
a = b;
}
if (is_snan(a->cls)) {
parts_silence_nan(a, s);
}
}
return a;
}
static FloatPartsN *partsN(pick_nan_muladd)(FloatPartsN *a, FloatPartsN *b,
FloatPartsN *c, float_status *s,
int ab_mask, int abc_mask)
{
int which;
if (unlikely(abc_mask & float_cmask_snan)) {
float_raise(float_flag_invalid, s);
}
which = pickNaNMulAdd(a->cls, b->cls, c->cls,
ab_mask == float_cmask_infzero, s);
if (s->default_nan_mode || which == 3) {
/*
* Note that this check is after pickNaNMulAdd so that function
* has an opportunity to set the Invalid flag for infzero.
*/
parts_default_nan(a, s);
return a;
}
switch (which) {
case 0:
break;
case 1:
a = b;
break;
case 2:
a = c;
break;
default:
g_assert_not_reached();
}
if (is_snan(a->cls)) {
parts_silence_nan(a, s);
}
return a;
}
/*
* Canonicalize the FloatParts structure. Determine the class,
* unbias the exponent, and normalize the fraction.
*/
static void partsN(canonicalize)(FloatPartsN *p, float_status *status,
const FloatFmt *fmt)
{
if (unlikely(p->exp == 0)) {
if (likely(frac_eqz(p))) {
p->cls = float_class_zero;
} else if (status->flush_inputs_to_zero) {
float_raise(float_flag_input_denormal, status);
p->cls = float_class_zero;
frac_clear(p);
} else {
int shift = frac_normalize(p);
p->cls = float_class_normal;
p->exp = fmt->frac_shift - fmt->exp_bias - shift + 1;
}
} else if (likely(p->exp < fmt->exp_max) || fmt->arm_althp) {
p->cls = float_class_normal;
p->exp -= fmt->exp_bias;
frac_shl(p, fmt->frac_shift);
p->frac_hi |= DECOMPOSED_IMPLICIT_BIT;
} else if (likely(frac_eqz(p))) {
p->cls = float_class_inf;
} else {
frac_shl(p, fmt->frac_shift);
p->cls = (parts_is_snan_frac(p->frac_hi, status)
? float_class_snan : float_class_qnan);
}
}
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