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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>
62 lines
1.6 KiB
C++
62 lines
1.6 KiB
C++
/*
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* Floating point arithmetic implementation
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*
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* The code in this source file is derived from release 2a of the SoftFloat
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* IEC/IEEE Floating-point Arithmetic Package. Those parts of the code (and
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* some later contributions) are provided under that license, as detailed below.
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* It has subsequently been modified by contributors to the QEMU Project,
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* so some portions are provided under:
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* the SoftFloat-2a license
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* the BSD license
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* GPL-v2-or-later
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*
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* Any future contributions to this file after December 1st 2014 will be
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* taken to be licensed under the Softfloat-2a license unless specifically
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* indicated otherwise.
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*/
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static void partsN(add_normal)(FloatPartsN *a, FloatPartsN *b)
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{
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int exp_diff = a->exp - b->exp;
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if (exp_diff > 0) {
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frac_shrjam(b, exp_diff);
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} else if (exp_diff < 0) {
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frac_shrjam(a, -exp_diff);
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a->exp = b->exp;
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}
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if (frac_add(a, a, b)) {
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frac_shrjam(a, 1);
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a->frac_hi |= DECOMPOSED_IMPLICIT_BIT;
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a->exp += 1;
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}
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}
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static bool partsN(sub_normal)(FloatPartsN *a, FloatPartsN *b)
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{
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int exp_diff = a->exp - b->exp;
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int shift;
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if (exp_diff > 0) {
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frac_shrjam(b, exp_diff);
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frac_sub(a, a, b);
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} else if (exp_diff < 0) {
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a->exp = b->exp;
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a->sign ^= 1;
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frac_shrjam(a, -exp_diff);
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frac_sub(a, b, a);
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} else if (frac_sub(a, a, b)) {
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/* Overflow means that A was less than B. */
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frac_neg(a);
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a->sign ^= 1;
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}
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shift = frac_normalize(a);
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if (likely(shift < N)) {
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a->exp -= shift;
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return true;
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}
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a->cls = float_class_zero;
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return false;
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}
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