30 lines
833 B
C
30 lines
833 B
C
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#include "tommath_private.h"
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#ifdef MP_ADD_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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/* high level addition (handles signs) */
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mp_err mp_add(const mp_int *a, const mp_int *b, mp_int *c)
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{
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/* handle two cases, not four */
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if (a->sign == b->sign) {
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/* both positive or both negative */
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/* add their magnitudes, copy the sign */
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c->sign = a->sign;
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return s_mp_add(a, b, c);
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}
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/* one positive, the other negative */
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/* subtract the one with the greater magnitude from */
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/* the one of the lesser magnitude. The result gets */
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/* the sign of the one with the greater magnitude. */
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if (mp_cmp_mag(a, b) == MP_LT) {
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MP_EXCH(const mp_int *, a, b);
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}
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c->sign = a->sign;
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return s_mp_sub(a, b, c);
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}
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#endif
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