In bignum_remainder, replaced special case for remainder by `1' with a

special case for remainder by small power of two.

diff --git a/v7/src/microcode/bignum.c b/v7/src/microcode/bignum.c
index 8a7c70d20c7a8bffbb772d01d7fdfaf9eb92f5cb..d03fa15054e608afd2a457eb4a2a4df51dac8060 100644 (file)
--- a/v7/src/microcode/bignum.c
+++ b/v7/src/microcode/bignum.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Id: bignum.c,v 9.44 1997/04/23 05:40:11 cph Exp $
+$Id: bignum.c,v 9.45 1997/07/04 16:02:18 adams Exp $
 
 Copyright (c) 1989-97 Massachusetts Institute of Technology
 
@@ -426,8 +426,17 @@ DEFUN (bignum_remainder, (numerator, denominator),
        if ((BIGNUM_LENGTH (denominator)) == 1)
          {
            bignum_digit_type digit = (BIGNUM_REF (denominator, 0));
-           if (digit == 1)
-             return (BIGNUM_ZERO ());
+           if ((digit & (digit-1)) == 0) /* i.e. digit = 2^k, including 1 */
+             {
+               bignum_digit_type unsigned_remainder;
+               if (BIGNUM_LENGTH (numerator) == 0)
+                 return (BIGNUM_ZERO ());
+               unsigned_remainder = (digit-1) & (BIGNUM_REF (numerator, 0));
+               if (unsigned_remainder == 0)
+                 return (BIGNUM_ZERO ());
+               return (bignum_digit_to_bignum
+                       (unsigned_remainder, BIGNUM_NEGATIVE_P (numerator)));
+             }
            if (digit < BIGNUM_RADIX_ROOT)
              return
                (bignum_remainder_unsigned_small_denominator