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Fix TFM mp_set_int to handle long. Enhance mp_set_int to use mp_set if less than max mp_digit. Added new MP_SET_CHUNK_BITS to eliminate hard coded const’s and allow build time adjustment.

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This commit is contained in:
David Garske
2017-03-15 12:23:50 -07:00
parent 4725a8aea6
commit 5a24fd9237
4 changed files with 57 additions and 14 deletions
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27
wolfcrypt/src/integer.c
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@@ -3903,25 +3903,32 @@ int fast_s_mp_mul_high_digs (mp_int * a, mp_int * b, mp_int * c, int digs)
}
/* set a 32-bit const */
#ifndef MP_SET_CHUNK_BITS
#define MP_SET_CHUNK_BITS 4
#endif
int mp_set_int (mp_int * a, unsigned long b)
{
int x, res;
int x, res;
/* use direct mp_set if b is less than mp_digit max */
if (b < MP_DIGIT_MAX) {
return mp_set (a, b);
}
mp_zero (a);
/* set four bits at a time */
for (x = 0; x < 8; x++) {
/* shift the number up four bits */
if ((res = mp_mul_2d (a, 4, a)) != MP_OKAY) {
/* set chunk bits at a time */
for (x = 0; x < (int)(sizeof(long) * 8) / MP_SET_CHUNK_BITS; x++) {
/* shift the number up chunk bits */
if ((res = mp_mul_2d (a, MP_SET_CHUNK_BITS, a)) != MP_OKAY) {
return res;
}
/* OR in the top four bits of the source */
a->dp[0] |= (b >> 28) & 15;
/* OR in the top bits of the source */
a->dp[0] |= (b >> (32 - MP_SET_CHUNK_BITS)) & ((1 << MP_SET_CHUNK_BITS) - 1);
/* shift the source up to the next four bits */
b <<= 4;
/* shift the source up to the next chunk bits */
b <<= MP_SET_CHUNK_BITS;
/* ensure that digits are not clamped off */
a->used += 1;