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replace mp_set_long() implementation by macro

This commit is contained in:
Steffen Jaeckel 2014-12-10 18:32:44 +01:00
parent 5d3ee880aa
commit f88e6a042a
2 changed files with 35 additions and 26 deletions
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27
bn_mp_set_long.c
View File

@ -16,32 +16,7 @@
*/
/* set a platform dependent unsigned long int */
int mp_set_long (mp_int * a, unsigned long b)
{
unsigned int x;
int res;
mp_zero (a);
/* set four bits at a time */
for (x = 0; x < sizeof(unsigned long) * 2; x++) {
/* shift the number up four bits */
if ((res = mp_mul_2d (a, 4, a)) != MP_OKAY) {
return res;
}
/* OR in the top four bits of the source */
a->dp[0] |= (b >> ((sizeof(unsigned long)) * 8 - 4)) & 15;
/* shift the source up to the next four bits */
b <<= 4;
/* ensure that digits are not clamped off */
a->used += 1;
}
mp_clamp (a);
return MP_OKAY;
}
MP_SET_XLONG(mp_set_long, unsigned long)
#endif
/* $Source$ */

34
tommath.h
View File

@ -596,6 +596,40 @@ void bn_reverse(unsigned char *s, int len);
extern const char *mp_s_rmap;
/* Fancy macro to set an MPI from another type.
* There are several things assumed:
* x is the counter and unsigned
* a is the pointer to the MPI
* b is the original value that should be set in the MPI.
*/
#define MP_SET_XLONG(func_name, type) \
int func_name (mp_int * a, type b) \
{ \
unsigned int x; \
int res; \
\
mp_zero (a); \
\
/* set four bits at a time */ \
for (x = 0; x < sizeof(type) * 2; x++) { \
/* shift the number up four bits */ \
if ((res = mp_mul_2d (a, 4, a)) != MP_OKAY) { \
return res; \
} \
\
/* OR in the top four bits of the source */ \
a->dp[0] |= (b >> ((sizeof(type)) * 8 - 4)) & 15; \
\
/* shift the source up to the next four bits */ \
b <<= 4; \
\
/* ensure that digits are not clamped off */ \
a->used += 1; \
} \
mp_clamp (a); \
return MP_OKAY; \
}
#ifdef __cplusplus
}
#endif