dropbear/libtommath/bn_mp_add.c
Steffen Jaeckel 615ed4e46a update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
* make key-generation compliant to FIPS 186.4

* fix includes in tommath_class.h

* update fuzzcorpus instead of error-out

* fixup fuzzing make-targets

* update Makefile.in

* apply necessary patches to ltm sources

* clean-up not required ltm files

* update to vanilla ltm 1.1.0

this already only contains the required files

* remove set/get double
2019-09-16 21:50:38 +08:00

51 lines
1.4 KiB
C

#include "tommath_private.h"
#ifdef BN_MP_ADD_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
* LibTomMath is a library that provides multiple-precision
* integer arithmetic as well as number theoretic functionality.
*
* The library was designed directly after the MPI library by
* Michael Fromberger but has been written from scratch with
* additional optimizations in place.
*
* SPDX-License-Identifier: Unlicense
*/
/* high level addition (handles signs) */
int mp_add(const mp_int *a, const mp_int *b, mp_int *c)
{
int sa, sb, res;
/* get sign of both inputs */
sa = a->sign;
sb = b->sign;
/* handle two cases, not four */
if (sa == sb) {
/* both positive or both negative */
/* add their magnitudes, copy the sign */
c->sign = sa;
res = s_mp_add(a, b, c);
} else {
/* one positive, the other negative */
/* subtract the one with the greater magnitude from */
/* the one of the lesser magnitude. The result gets */
/* the sign of the one with the greater magnitude. */
if (mp_cmp_mag(a, b) == MP_LT) {
c->sign = sb;
res = s_mp_sub(b, a, c);
} else {
c->sign = sa;
res = s_mp_sub(a, b, c);
}
}
return res;
}
#endif
/* ref: HEAD -> master, tag: v1.1.0 */
/* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
/* commit time: 2019-01-28 20:32:32 +0100 */