ec-bin (ec_binproj): Make curve setup faster.

[u/mdw/catacomb] / mpmont-mexp.c

diff --git a/mpmont-mexp.c b/mpmont-mexp.c
index 7589990..ce46fef 100644 (file)
--- a/mpmont-mexp.c
+++ b/mpmont-mexp.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: mpmont-mexp.c,v 1.8 2004/04/01 12:50:09 mdw Exp $
+ * $Id$
  *
  * Multiple simultaneous exponentiations
  *
@@ -27,42 +27,6 @@
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: mpmont-mexp.c,v $
- * Revision 1.8  2004/04/01 12:50:09  mdw
- * Add cyclic group abstraction, with test code.  Separate off exponentation
- * functions for better static linking.  Fix a buttload of bugs on the way.
- * Generally ensure that negative exponents do inversion correctly.  Add
- * table of standard prime-field subgroups.  (Binary field subgroups are
- * currently unimplemented but easy to add if anyone ever finds a good one.)
- *
- * Revision 1.7  2002/01/13 13:49:14  mdw
- * Make @const@-correct.
- *
- * Revision 1.6  2001/06/16 13:00:20  mdw
- * Use the generic exponentiation functions.
- *
- * Revision 1.5  2000/10/08 12:11:22  mdw
- * Use @MP_EQ@ instead of @MP_CMP@.
- *
- * Revision 1.4  2000/06/17 11:45:09  mdw
- * Major memory management overhaul.  Added arena support.  Use the secure
- * arena for secret integers.  Replace and improve the MP management macros
- * (e.g., replace MP_MODIFY by MP_DEST).
- *
- * Revision 1.3  1999/12/10 23:18:39  mdw
- * Change interface for suggested destinations.
- *
- * Revision 1.2  1999/11/21 11:35:10  mdw
- * Performance improvement: use @mp_sqr@ and @mpmont_reduce@ instead of
- * @mpmont_mul@ for squaring in exponentiation.
- *
- * Revision 1.1  1999/11/19 13:19:29  mdw
- * Simultaneous exponentiation support.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include "mp.h"
@@ -93,21 +57,18 @@ static mp *mexpr(mpmont *mm, mp *d, mp_expfactor *f, size_t n)
 {
   mp *a = MP_COPY(mm->r);
   mp *spare = MP_NEW;
-  mp *g = MP_NEW;
   size_t i;
 
   for (i = 0; i < n; i++) {
     mp *t;
     if (f[i].exp->f & MP_BURN)
       spare = MP_NEWSEC;
-    if (f[i].exp->f & MP_NEG) {
+    if (MP_NEGP(f[i].exp)) {
       t = mpmont_reduce(mm, f[i].base, f[i].base);
-      mp_gcd(&g, 0, &t, mm->m, t);
-      assert(MP_EQ(g, MP_ONE));
+      t = mp_modinv(t, t, mm->m);
       f[i].base = mpmont_mul(mm, t, t, mm->r2);
     }
   }
-  mp_drop(g);
   EXP_SIMUL(a, f, n);
   mp_drop(d);
   mp_drop(spare);