da10a9074a
In preparation for implementing multiple sizes. Rename to parts_addsub, split out parts_add/sub_normal for future reuse with muladd. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
/*
|
|
* Floating point arithmetic implementation
|
|
*
|
|
* 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(add_normal)(FloatPartsN *a, FloatPartsN *b)
|
|
{
|
|
int exp_diff = a->exp - b->exp;
|
|
|
|
if (exp_diff > 0) {
|
|
frac_shrjam(b, exp_diff);
|
|
} else if (exp_diff < 0) {
|
|
frac_shrjam(a, -exp_diff);
|
|
a->exp = b->exp;
|
|
}
|
|
|
|
if (frac_add(a, a, b)) {
|
|
frac_shrjam(a, 1);
|
|
a->frac_hi |= DECOMPOSED_IMPLICIT_BIT;
|
|
a->exp += 1;
|
|
}
|
|
}
|
|
|
|
static bool partsN(sub_normal)(FloatPartsN *a, FloatPartsN *b)
|
|
{
|
|
int exp_diff = a->exp - b->exp;
|
|
int shift;
|
|
|
|
if (exp_diff > 0) {
|
|
frac_shrjam(b, exp_diff);
|
|
frac_sub(a, a, b);
|
|
} else if (exp_diff < 0) {
|
|
a->exp = b->exp;
|
|
a->sign ^= 1;
|
|
frac_shrjam(a, -exp_diff);
|
|
frac_sub(a, b, a);
|
|
} else if (frac_sub(a, a, b)) {
|
|
/* Overflow means that A was less than B. */
|
|
frac_neg(a);
|
|
a->sign ^= 1;
|
|
}
|
|
|
|
shift = frac_normalize(a);
|
|
if (likely(shift < N)) {
|
|
a->exp -= shift;
|
|
return true;
|
|
}
|
|
a->cls = float_class_zero;
|
|
return false;
|
|
}
|