Imported gcc-4.4.3

[msp430-gcc.git] / gmp / mpz / remove.c

diff --git a/gmp/mpz/remove.c b/gmp/mpz/remove.c
new file mode 100644 (file)
index 0000000..1e5474b
--- /dev/null
+++ b/gmp/mpz/remove.c
@@ -0,0 +1,92 @@
+/* mpz_remove -- divide out a factor and return its multiplicity.
+
+Copyright 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+The GNU MP Library 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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+
+unsigned long int
+mpz_remove (mpz_ptr dest, mpz_srcptr src, mpz_srcptr f)
+{
+  mpz_t fpow[40];              /* inexhaustible...until year 2020 or so */
+  mpz_t x, rem;
+  unsigned long int pwr;
+  int p;
+
+  if (mpz_cmp_ui (f, 1) <= 0)
+    DIVIDE_BY_ZERO;
+
+  if (SIZ (src) == 0)
+    {
+      if (src != dest)
+        mpz_set (dest, src);
+      return 0;
+    }
+
+  if (mpz_cmp_ui (f, 2) == 0)
+    {
+      unsigned long int s0;
+      s0 = mpz_scan1 (src, 0);
+      mpz_div_2exp (dest, src, s0);
+      return s0;
+    }
+
+  /* We could perhaps compute mpz_scan1(src,0)/mpz_scan1(f,0).  It is an
+     upper bound of the result we're seeking.  We could also shift down the
+     operands so that they become odd, to make intermediate values smaller.  */
+
+  mpz_init (rem);
+  mpz_init (x);
+
+  pwr = 0;
+  mpz_init (fpow[0]);
+  mpz_set (fpow[0], f);
+  mpz_set (dest, src);
+
+  /* Divide by f, f^2, ..., f^(2^k) until we get a remainder for f^(2^k).  */
+  for (p = 0;; p++)
+    {
+      mpz_tdiv_qr (x, rem, dest, fpow[p]);
+      if (SIZ (rem) != 0)
+       break;
+      mpz_init (fpow[p + 1]);
+      mpz_mul (fpow[p + 1], fpow[p], fpow[p]);
+      mpz_set (dest, x);
+    }
+
+  pwr = (1 << p) - 1;
+
+  mpz_clear (fpow[p]);
+
+  /* Divide by f^(2^(k-1)), f^(2^(k-2)), ..., f for all divisors that give a
+     zero remainder.  */
+  while (--p >= 0)
+    {
+      mpz_tdiv_qr (x, rem, dest, fpow[p]);
+      if (SIZ (rem) == 0)
+       {
+         pwr += 1 << p;
+         mpz_set (dest, x);
+       }
+      mpz_clear (fpow[p]);
+    }
+
+  mpz_clear (x);
+  mpz_clear (rem);
+  return pwr;
+}