X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/b817bfc642225b8c3c0b6a7e42d1fb949b61a606..95ccefe3ce59a0773f915aca6948d5b6f1f7c882:/gf-arith.c

diff --git a/gf-arith.c b/gf-arith.c
index c23aa19..5a7b3f2 100644
--- a/gf-arith.c
+++ b/gf-arith.c
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: gf-arith.c,v 1.4 2004/04/08 01:36:15 mdw Exp $
+ * $Id$
  *
  * Basic arithmetic on binary polynomials
  *
  * (c) 2004 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of Catacomb.
  *
@@ -15,12 +15,12 @@
  * it under the terms of the GNU Library General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
- * 
+ *
  * Catacomb is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Library General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Library General Public
  * License along with Catacomb; if not, write to the Free
  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
@@ -179,11 +179,17 @@ void gf_div(mp **qq, mp **rr, mp *a, mp *b)
 
 int gf_irreduciblep(mp *f)
 {
-  unsigned long m = mp_bits(f) - 1;
+  unsigned long m;
   mp *u = MP_TWO;
   mp *v = MP_NEW;
 
-  m /= 2;
+  if (MP_ZEROP(f))
+    return (0);
+  else if (MP_LEN(f) == 1) {
+    if (f->v[0] < 2) return (0);
+    if (f->v[0] < 4) return (1);
+  }
+  m = (mp_bits(f) - 1)/2;
   while (m) {
     u = gf_sqr(u, u);
     gf_div(0, &u, u, f);
@@ -205,8 +211,8 @@ static int verify(const char *op, mp *expect, mp *result, mp *a, mp *b)
 {
   if (!MP_EQ(expect, result)) {
     fprintf(stderr, "\n*** %s failed", op);
-    fputs("\n*** a      = ", stderr); mp_writefile(a, stderr, 16);
-    fputs("\n*** b      = ", stderr); mp_writefile(b, stderr, 16);
+    fputs("\n*** a	= ", stderr); mp_writefile(a, stderr, 16);
+    fputs("\n*** b	= ", stderr); mp_writefile(b, stderr, 16);
     fputs("\n*** result = ", stderr); mp_writefile(result, stderr, 16);
     fputs("\n*** expect = ", stderr); mp_writefile(expect, stderr, 16);
     fputc('\n', stderr);
@@ -230,6 +236,7 @@ static int verify(const char *op, mp *expect, mp *result, mp *a, mp *b)
 
 RIG(add, gf_add)
 RIG(mul, gf_mul)
+RIG(exp, gf_exp)
 
 #undef RIG
 
@@ -271,9 +278,9 @@ static int tirred(dstr *v)
   if (r != c) {
     ok = 0;
     fprintf(stderr, "\n*** irred failed");
-    fputs("\n*** a      = ", stderr); mp_writefile(a, stderr, 16);
-    fprintf(stderr, "\n*** r      = %d\n", r);
-    fprintf(stderr, "*** c      = %d\n", c);
+    fputs("\n*** a	= ", stderr); mp_writefile(a, stderr, 16);
+    fprintf(stderr, "\n*** r	  = %d\n", r);
+    fprintf(stderr, "*** c	= %d\n", c);
   }
   mp_drop(a);
   assert(mparena_count(MPARENA_GLOBAL) == 0);
@@ -285,6 +292,7 @@ static test_chunk tests[] = {
   { "mul", tmul, { &type_mp, &type_mp, &type_mp, 0 } },
   { "sqr", tsqr, { &type_mp, &type_mp, 0 } },
   { "div", tdiv, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } },
+  { "exp", texp, { &type_mp, &type_mp, &type_mp, 0 } },
   { "irred", tirred, { &type_mp, &type_int, 0 } },
   { 0, 0, { 0 } },
 };