summaryrefslogtreecommitdiff
path: root/Build/source/libs/mpfr/mpfr-3.1.2/src/eq.c
diff options
context:
space:
mode:
Diffstat (limited to 'Build/source/libs/mpfr/mpfr-3.1.2/src/eq.c')
-rw-r--r--Build/source/libs/mpfr/mpfr-3.1.2/src/eq.c141
1 files changed, 141 insertions, 0 deletions
diff --git a/Build/source/libs/mpfr/mpfr-3.1.2/src/eq.c b/Build/source/libs/mpfr/mpfr-3.1.2/src/eq.c
new file mode 100644
index 00000000000..75890702575
--- /dev/null
+++ b/Build/source/libs/mpfr/mpfr-3.1.2/src/eq.c
@@ -0,0 +1,141 @@
+/* mpfr_eq -- Compare two floats up to a specified bit #.
+
+Copyright 1999, 2001, 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
+Contributed by the AriC and Caramel projects, INRIA.
+
+This file is part of the GNU MPFR Library.
+
+The GNU MPFR 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 MPFR 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 MPFR Library; see the file COPYING.LESSER. If not, see
+http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
+51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+
+#include "mpfr-impl.h"
+
+/* return non-zero if the first n_bits bits of u, v are equal,
+ 0 otherwise */
+int
+mpfr_eq (mpfr_srcptr u, mpfr_srcptr v, unsigned long int n_bits)
+{
+ mpfr_limb_srcptr up, vp;
+ mp_size_t usize, vsize, size, i;
+ mpfr_exp_t uexp, vexp;
+ int k;
+
+ if (MPFR_ARE_SINGULAR(u, v))
+ {
+ if (MPFR_IS_NAN(u) || MPFR_IS_NAN(v))
+ return 0; /* non equal */
+ else if (MPFR_IS_INF(u) && MPFR_IS_INF(v))
+ return (MPFR_SIGN(u) == MPFR_SIGN(v));
+ else if (MPFR_IS_ZERO(u) && MPFR_IS_ZERO(v))
+ return 1;
+ else
+ return 0;
+ }
+
+ /* 1. Are the signs different? */
+ if (MPFR_SIGN(u) != MPFR_SIGN(v))
+ return 0;
+
+ uexp = MPFR_GET_EXP (u);
+ vexp = MPFR_GET_EXP (v);
+
+ /* 2. Are the exponents different? */
+ if (uexp != vexp)
+ return 0; /* no bit agree */
+
+ usize = MPFR_LIMB_SIZE (u);
+ vsize = MPFR_LIMB_SIZE (v);
+
+ if (vsize > usize) /* exchange u and v */
+ {
+ up = MPFR_MANT(v);
+ vp = MPFR_MANT(u);
+ size = vsize;
+ vsize = usize;
+ usize = size;
+ }
+ else
+ {
+ up = MPFR_MANT(u);
+ vp = MPFR_MANT(v);
+ }
+
+ /* now usize >= vsize */
+ MPFR_ASSERTD(usize >= vsize);
+
+ if (usize > vsize)
+ {
+ if ((unsigned long) vsize * GMP_NUMB_BITS < n_bits)
+ {
+ /* check if low min(PREC(u), n_bits) - (vsize * GMP_NUMB_BITS)
+ bits from u are non-zero */
+ unsigned long remains = n_bits - (vsize * GMP_NUMB_BITS);
+ k = usize - vsize - 1;
+ while (k >= 0 && remains >= GMP_NUMB_BITS && !up[k])
+ {
+ k--;
+ remains -= GMP_NUMB_BITS;
+ }
+ /* now either k < 0: all low bits from u are zero
+ or remains < GMP_NUMB_BITS: check high bits from up[k]
+ or up[k] <> 0: different */
+ if (k >= 0 && (((remains < GMP_NUMB_BITS) &&
+ (up[k] >> (GMP_NUMB_BITS - remains))) ||
+ (remains >= GMP_NUMB_BITS && up[k])))
+ return 0; /* surely too different */
+ }
+ size = vsize;
+ }
+ else
+ {
+ size = usize;
+ }
+
+ /* now size = min (usize, vsize) */
+
+ /* If size is too large wrt n_bits, reduce it to look only at the
+ high n_bits bits.
+ Otherwise, if n_bits > size * GMP_NUMB_BITS, reduce n_bits to
+ size * GMP_NUMB_BITS, since the extra low bits of one of the
+ operands have already been check above. */
+ if ((unsigned long) size > 1 + (n_bits - 1) / GMP_NUMB_BITS)
+ size = 1 + (n_bits - 1) / GMP_NUMB_BITS;
+ else if (n_bits > (unsigned long) size * GMP_NUMB_BITS)
+ n_bits = size * GMP_NUMB_BITS;
+
+ up += usize - size;
+ vp += vsize - size;
+
+ for (i = size - 1; i > 0 && n_bits >= GMP_NUMB_BITS; i--)
+ {
+ if (up[i] != vp[i])
+ return 0;
+ n_bits -= GMP_NUMB_BITS;
+ }
+
+ /* now either i=0 or n_bits<GMP_NUMB_BITS */
+
+ /* since n_bits <= size * GMP_NUMB_BITS before the above for-loop,
+ we have the invariant n_bits <= (i+1) * GMP_NUMB_BITS, thus
+ we always have n_bits <= GMP_NUMB_BITS here */
+ MPFR_ASSERTD(n_bits <= GMP_NUMB_BITS);
+
+ if (n_bits & (GMP_NUMB_BITS - 1))
+ return (up[i] >> (GMP_NUMB_BITS - (n_bits & (GMP_NUMB_BITS - 1))) ==
+ vp[i] >> (GMP_NUMB_BITS - (n_bits & (GMP_NUMB_BITS - 1))));
+ else
+ return (up[i] == vp[i]);
+}