Merge remote-tracking branch 'dbussink/master'
This commit is contained in:
commit
2e781717db
|
@ -18,7 +18,7 @@
|
|||
/* calculate c = a**b using a square-multiply algorithm */
|
||||
int mp_expt_d (mp_int * a, mp_digit b, mp_int * c)
|
||||
{
|
||||
int res, x;
|
||||
int res;
|
||||
mp_int g;
|
||||
|
||||
if ((res = mp_init_copy (&g, a)) != MP_OKAY) {
|
||||
|
@ -28,23 +28,23 @@ int mp_expt_d (mp_int * a, mp_digit b, mp_int * c)
|
|||
/* set initial result */
|
||||
mp_set (c, 1);
|
||||
|
||||
for (x = 0; x < (int) DIGIT_BIT; x++) {
|
||||
while (b > 0) {
|
||||
/* if the bit is set multiply */
|
||||
if (b & 1) {
|
||||
if ((res = mp_mul (c, &g, c)) != MP_OKAY) {
|
||||
mp_clear (&g);
|
||||
return res;
|
||||
}
|
||||
}
|
||||
|
||||
/* square */
|
||||
if ((res = mp_sqr (c, c)) != MP_OKAY) {
|
||||
if (b > 1 && (res = mp_sqr (&g, &g)) != MP_OKAY) {
|
||||
mp_clear (&g);
|
||||
return res;
|
||||
}
|
||||
|
||||
/* if the bit is set multiply */
|
||||
if ((b & (mp_digit) (((mp_digit)1) << (DIGIT_BIT - 1))) != 0) {
|
||||
if ((res = mp_mul (c, &g, c)) != MP_OKAY) {
|
||||
mp_clear (&g);
|
||||
return res;
|
||||
}
|
||||
}
|
||||
|
||||
/* shift to next bit */
|
||||
b <<= 1;
|
||||
b >>= 1;
|
||||
}
|
||||
|
||||
mp_clear (&g);
|
||||
|
|
Loading…
Reference in New Issue