X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/f4535c6454395e6d56ce0091a07b6d4f7d54a47f..cc3ca08f22460b15423bb88632f3a12741b19003:/gf-arith.c

diff --git a/gf-arith.c b/gf-arith.c
index f380a35..5a7b3f2 100644
--- a/gf-arith.c
+++ b/gf-arith.c
@@ -7,7 +7,7 @@
  * (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);
@@ -272,9 +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);