diff options
Diffstat (limited to 'libtommath/bn_mp_sub_d.c')
| -rw-r--r-- | libtommath/bn_mp_sub_d.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/libtommath/bn_mp_sub_d.c b/libtommath/bn_mp_sub_d.c index 7016abc..4d66a90 100644 --- a/libtommath/bn_mp_sub_d.c +++ b/libtommath/bn_mp_sub_d.c @@ -16,7 +16,7 @@ */ /* single digit subtraction */ -int mp_sub_d(mp_int *a, mp_digit b, mp_int *c) +int mp_sub_d(const mp_int *a, mp_digit b, mp_int *c) { mp_digit *tmpa, *tmpc, mu; int res, ix, oldused; @@ -32,9 +32,10 @@ int mp_sub_d(mp_int *a, mp_digit b, mp_int *c) * addition [with fudged signs] */ if (a->sign == MP_NEG) { - a->sign = MP_ZPOS; - res = mp_add_d(a, b, c); - a->sign = c->sign = MP_NEG; + mp_int a_ = *a; + a_.sign = MP_ZPOS; + res = mp_add_d(&a_, b, c); + c->sign = MP_NEG; /* clamp */ mp_clamp(c); |