Imported gcc-4.4.3

[msp430-gcc.git] / gmp / mpf / eq.c

diff --git a/gmp/mpf/eq.c b/gmp/mpf/eq.c
new file mode 100644 (file)
index 0000000..9395b68
--- /dev/null
+++ b/gmp/mpf/eq.c
@@ -0,0 +1,119 @@
+/* mpf_eq -- Compare two floats up to a specified bit #.
+
+Copyright 1993, 1995, 1996, 2001, 2002, 2008 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
+mpf_eq (mpf_srcptr u, mpf_srcptr v, unsigned long int n_bits)
+{
+  mp_srcptr up, vp;
+  mp_size_t usize, vsize, size, i;
+  mp_exp_t uexp, vexp;
+  mp_limb_t diff;
+  int cnt;
+
+  uexp = u->_mp_exp;
+  vexp = v->_mp_exp;
+
+  usize = u->_mp_size;
+  vsize = v->_mp_size;
+
+  /* 1. Are the signs different?  */
+  if ((usize ^ vsize) >= 0)
+    {
+      /* U and V are both non-negative or both negative.  */
+      if (usize == 0)
+       return vsize == 0;
+      if (vsize == 0)
+       return 0;
+
+      /* Fall out.  */
+    }
+  else
+    {
+      /* Either U or V is negative, but not both.  */
+      return 0;
+    }
+
+  /* U and V have the same sign and are both non-zero.  */
+
+  /* 2. Are the exponents different?  */
+  if (uexp != vexp)
+    return 0;
+
+  usize = ABS (usize);
+  vsize = ABS (vsize);
+
+  up = u->_mp_d;
+  vp = v->_mp_d;
+
+  /* Ignore zeroes at the low end of U and V.  */
+  while (up[0] == 0)
+    {
+      up++;
+      usize--;
+    }
+  while (vp[0] == 0)
+    {
+      vp++;
+      vsize--;
+    }
+
+  if (usize > vsize)
+    {
+      if (vsize * GMP_NUMB_BITS < n_bits)
+       return 0;               /* surely too different */
+      size = vsize;
+    }
+  else if (vsize > usize)
+    {
+      if (usize * GMP_NUMB_BITS < n_bits)
+       return 0;               /* surely too different */
+      size = usize;
+    }
+  else
+    {
+      size = usize;
+    }
+
+  up += usize;                 /* point just above most significant limb */
+  vp += vsize;                 /* point just above most significant limb */
+
+  count_leading_zeros (cnt, up[-1]);
+  if ((vp[-1] >> (GMP_LIMB_BITS - 1 - cnt)) != 1)
+    return 0;                  /* msb positions different */
+
+  n_bits += cnt - GMP_NAIL_BITS;
+
+  size = MIN (size, (n_bits + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS);
+
+  up -= size;                  /* point at least significant relevant limb */
+  vp -= size;                  /* point at least significant relevant limb */
+
+  for (i = size - 1; i > 0; i--)
+    {
+      if (up[i] != vp[i])
+       return 0;
+    }
+
+  diff = (up[0] ^ vp[0]) >> (GMP_NUMB_BITS - 1 - (n_bits - 1) % GMP_NUMB_BITS);
+  return diff == 0;
+}