X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/34e4f738bcba58e6d8c4cabbb0b3232a65b42a9d..c65df27983057ec76ed0e72bb370f9a5ae7dad28:/mpx.c

diff --git a/mpx.c b/mpx.c
index 1591f98..e122760 100644
--- a/mpx.c
+++ b/mpx.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: mpx.c,v 1.18 2004/04/01 12:50:09 mdw Exp $
+ * $Id: mpx.c,v 1.20 2004/04/08 01:36:15 mdw Exp $
  *
  * Low-level multiprecision arithmetic
  *
@@ -27,71 +27,6 @@
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: mpx.c,v $
- * Revision 1.18  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 1.17  2004/03/27 00:04:46  mdw
- * Implement efficient reduction for pleasant-looking primes.
- *
- * Revision 1.16  2003/05/16 09:09:24  mdw
- * Fix @mp_lsl2c@.  Turns out to be surprisingly tricky.
- *
- * Revision 1.15  2002/10/20 01:12:31  mdw
- * Two's complement I/O fixes.
- *
- * Revision 1.14  2002/10/19 18:55:08  mdw
- * Fix overflows in shift primitives.
- *
- * Revision 1.13  2002/10/19 17:56:50  mdw
- * Fix bit operations.  Test them (a bit) better.
- *
- * Revision 1.12  2002/10/06 22:52:50  mdw
- * Pile of changes for supporting two's complement properly.
- *
- * Revision 1.11  2001/04/03 19:36:05  mdw
- * Add some simple bitwise operations so that Perl can use them.
- *
- * Revision 1.10  2000/10/08 12:06:12  mdw
- * Provide @mpx_ueq@ for rapidly testing equality of two integers.
- *
- * Revision 1.9  2000/06/26 07:52:50  mdw
- * Portability fix for the bug fix.
- *
- * Revision 1.8  2000/06/25 12:59:02  mdw
- * (mpx_udiv): Fix bug in quotient digit estimation.
- *
- * Revision 1.7  1999/12/22 15:49:07  mdw
- * New function for division by a small integer.
- *
- * Revision 1.6  1999/11/20 22:43:44  mdw
- * Integrate testing for MPX routines.
- *
- * Revision 1.5  1999/11/20 22:23:27  mdw
- * Add function versions of some low-level macros with wider use.
- *
- * Revision 1.4  1999/11/17 18:04:09  mdw
- * Add two's-complement functionality.  Improve mpx_udiv a little by
- * performing the multiplication of the divisor by q with the subtraction
- * from r.
- *
- * Revision 1.3  1999/11/13 01:57:31  mdw
- * Remove stray debugging code.
- *
- * Revision 1.2  1999/11/13 01:50:59  mdw
- * Multiprecision routines finished and tested.
- *
- * Revision 1.1  1999/09/03 08:41:12  mdw
- * Initial import.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include <assert.h>
@@ -660,7 +595,7 @@ void mpx_lsr(mpw *dv, mpw *dvl, const mpw *av, const mpw *avl, size_t n)
   /* --- Single bit shifting --- */
 
   else if (n == 1) {
-    mpw w = *av++ >> 1;
+    mpw w = av < avl ? *av++ >> 1 : 0;
     while (av < avl) {
       mpw t;
       if (dv >= dvl)