Imported gcc-4.4.3

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

diff --git a/gmp/mpz/divis_ui.c b/gmp/mpz/divis_ui.c
new file mode 100644 (file)
index 0000000..ead0ddd
--- /dev/null
+++ b/gmp/mpz/divis_ui.c
@@ -0,0 +1,70 @@
+/* mpz_divisible_ui_p -- mpz by ulong divisibility test.
+
+Copyright 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"
+#include "longlong.h"
+
+
+int
+mpz_divisible_ui_p (mpz_srcptr a, unsigned long d)
+{
+  mp_size_t  asize;
+  mp_ptr     ap;
+  unsigned   twos;
+
+  asize = SIZ(a);
+  if (UNLIKELY (d == 0))
+    return (asize == 0);
+
+  if (asize == 0)  /* 0 divisible by any d */
+    return 1;
+
+  /* For nails don't try to be clever if d is bigger than a limb, just fake
+     up an mpz_t and go to the main mpz_divisible_p.  */
+  if (d > GMP_NUMB_MAX)
+    {
+      mp_limb_t  dlimbs[2];
+      mpz_t      dz;
+      ALLOC(dz) = 2;
+      PTR(dz) = dlimbs;
+      mpz_set_ui (dz, d);
+      return mpz_divisible_p (a, dz);
+    }
+
+  ap = PTR(a);
+  asize = ABS(asize);  /* ignore sign of a */
+
+  if (BELOW_THRESHOLD (asize, MODEXACT_1_ODD_THRESHOLD))
+    return mpn_mod_1 (ap, asize, (mp_limb_t) d) == 0;
+
+  if (! (d & 1))
+    {
+      /* Strip low zero bits to get odd d required by modexact.  If d==e*2^n
+         and a is divisible by 2^n and by e, then it's divisible by d. */
+
+      if ((ap[0] & LOW_ZEROS_MASK (d)) != 0)
+        return 0;
+
+      count_trailing_zeros (twos, (mp_limb_t) d);
+      d >>= twos;
+    }
+
+  return mpn_modexact_1_odd (ap, asize, (mp_limb_t) d) == 0;
+}