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Change mp_add and mp_sub to not allocate a temporary variable unless it's

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really necessary.


git-svn-id: svn://10.0.0.236/trunk@76073 18797224-902f-48f8-a5cc-f745e15eee43
This commit is contained in:
nelsonb%netscape.com
2000-08-11 01:58:20 +00:00
parent 76985c2924
commit adc94749ec
1 changed files with 54 additions and 52 deletions
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106
mozilla/security/nss/lib/freebl/mpi/mpi.c
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@@ -35,7 +35,7 @@
* the GPL. If you do not delete the provisions above, a recipient
* may use your version of this file under either the MPL or the GPL.
*
* $Id: mpi.c,v 1.17 2000-08-10 21:43:16 nelsonb%netscape.com Exp $
* $Id: mpi.c,v 1.18 2000-08-11 01:58:20 nelsonb%netscape.com Exp $
*/
#include "mpi-priv.h"
@@ -82,6 +82,8 @@ static const char *s_dmap_1 =
unsigned long mp_allocs;
unsigned long mp_frees;
#define MP_CHECKOK(x) if (MP_OKAY > (res = (x))) goto CLEANUP
/* {{{ Default precision manipulation */
/* Default precision for newly created mp_int's */
@@ -136,6 +138,7 @@ mp_err mp_init_size(mp_int *mp, mp_size prec)
{
ARGCHK(mp != NULL && prec > 0, MP_BADARG);
prec = MP_ROUNDUP(prec, s_mp_defprec);
if((DIGITS(mp) = s_mp_alloc(prec, sizeof(mp_digit))) == NULL)
return MP_MEM;
@@ -704,32 +707,30 @@ mp_err mp_add(const mp_int *a, const mp_int *b, mp_int *c)
ARGCHK(a != NULL && b != NULL && c != NULL, MP_BADARG);
if(SIGN(a) == SIGN(b)) { /* same sign: add values, keep sign */
if((res = mp_init_copy(&tmp, a)) != MP_OKAY)
return res;
if((res = s_mp_add(&tmp, b)) != MP_OKAY)
goto CLEANUP;
} else if(s_mp_cmp(a, b) >= 0) { /* different sign: a >= b */
if((res = mp_init_copy(&tmp, a)) != MP_OKAY)
return res;
if((res = s_mp_sub(&tmp, b)) != MP_OKAY)
goto CLEANUP;
} else { /* different sign: a < b */
if((res = mp_init_copy(&tmp, b)) != MP_OKAY)
return res;
if((res = s_mp_sub(&tmp, a)) != MP_OKAY)
goto CLEANUP;
MP_DIGITS(&tmp) = 0;
if (c == a) {
MP_CHECKOK( mp_init_copy(&tmp, a) );
a = &tmp;
if (c == b)
b = &tmp;
} else if (c == b) {
MP_CHECKOK( mp_init_copy(&tmp, b) );
b = &tmp;
}
if(s_mp_cmp_d(&tmp, 0) == MP_EQ)
SIGN(&tmp) = ZPOS;
if(SIGN(a) == SIGN(b)) { /* same sign: add values, keep sign */
MP_CHECKOK( mp_copy(a, c) );
MP_CHECKOK( s_mp_add(c, b) );
} else if(s_mp_cmp(a, b) >= 0) { /* different sign: a >= b */
MP_CHECKOK( mp_copy(a, c) );
MP_CHECKOK( s_mp_sub(c, b) );
} else { /* different sign: a < b */
MP_CHECKOK( mp_copy(b, c) );
MP_CHECKOK( s_mp_sub(c, a) );
}
s_mp_exch(&tmp, c);
if (s_mp_cmp_d(c, 0) == MP_EQ)
SIGN(c) = ZPOS;
CLEANUP:
mp_clear(&tmp);
@@ -751,41 +752,44 @@ mp_err mp_sub(const mp_int *a, const mp_int *b, mp_int *c)
{
mp_int tmp;
mp_err res;
int diffSign;
ARGCHK(a != NULL && b != NULL && c != NULL, MP_BADARG);
if(SIGN(a) != SIGN(b)) {
if((res = mp_init_copy(&tmp, a)) != MP_OKAY)
return res;
if((res = s_mp_add(&tmp, b)) != MP_OKAY)
goto CLEANUP;
} else if(s_mp_cmp(a, b) >= 0) {
if((res = mp_init_copy(&tmp, a)) != MP_OKAY)
return res;
if((res = s_mp_sub(&tmp, b)) != MP_OKAY)
goto CLEANUP;
} else {
if((res = mp_init_copy(&tmp, b)) != MP_OKAY)
return res;
if((res = s_mp_sub(&tmp, a)) != MP_OKAY)
goto CLEANUP;
SIGN(&tmp) = (SIGN(a) == NEG) ? ZPOS : NEG;
MP_DIGITS(&tmp) = 0;
if (a == b) {
mp_zero(c);
return MP_OKAY;
}
if (c == a) {
MP_CHECKOK( mp_init_copy(&tmp, a) );
a = &tmp;
} else if (c == b) {
MP_CHECKOK( mp_init_copy(&tmp, b) );
b = &tmp;
}
if(s_mp_cmp_d(&tmp, 0) == 0)
SIGN(&tmp) = ZPOS;
if (MP_SIGN(a) != MP_SIGN(b)) {
MP_CHECKOK( mp_copy(a, c) );
MP_CHECKOK( s_mp_add(c, b) );
} else if (!(diffSign = s_mp_cmp(a, b))) {
mp_zero(c);
res = MP_OKAY;
} else if (diffSign > 0) {
MP_CHECKOK( mp_copy(a, c) );
MP_CHECKOK( s_mp_sub(c, b) );
} else {
MP_CHECKOK( mp_copy(b, c) );
MP_CHECKOK( s_mp_sub(c, a) );
MP_SIGN(c) = !MP_SIGN(a);
}
s_mp_exch(&tmp, c);
if (s_mp_cmp_d(c, 0) == MP_EQ)
MP_SIGN(c) = MP_ZPOS;
CLEANUP:
mp_clear(&tmp);
return MP_OKAY;
return res;
} /* end mp_sub() */
@@ -2039,8 +2043,6 @@ mp_err s_mp_almost_inverse(const mp_int *a, const mp_int *p, mp_int *c)
ARGCHK(a && p && c, MP_BADARG);
#define MP_CHECKOK(x) if (MP_OKAY > (res = (x))) goto CLEANUP
MP_DIGITS(&d) = 0;
MP_DIGITS(&f) = 0;
MP_DIGITS(&g) = 0;