File renaming.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@1714 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 71 insertions, 0 deletions

diff --git a/get_z_exp.c b/get_z_exp.c
new file mode 100644
index 000000000..c98b6bdd0
--- /dev/null
+++ b/get_z_exp.c
@@ -0,0 +1,71 @@
+/* mpfr_get_z_exp -- get a multiple-precision integer and an exponent
+                     from a floating-point number
+
+Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
+
+This file is part of the MPFR Library.
+
+The 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 2.1 of the License, or (at your
+option) any later version.
+
+The 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 MPFR Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+#include "mpfr.h"
+#include "mpfr-impl.h"
+
+/* puts the mantissa of f into z, and returns 'exp' such that f = z * 2^exp
+ *
+ * 0 doesn't have an exponent, therefore the returned exponent in this case
+ * isn't really important. We choose to return __mpfr_emin because
+ *   1) it is in the exponent range [__mpfr_emin,__mpfr_emax],
+ *   2) the smaller a number is (in absolute value), the smaller its
+ *      exponent is. In other words, the f -> exp function is monotonous
+ *      on nonnegative numbers.
+ * Note that this is different from the C function frexp().
+ */
+
+mp_exp_t
+mpfr_get_z_exp (mpz_ptr z, mpfr_srcptr f)
+{
+  mp_size_t fn;
+  int sh;
+
+  MPFR_ASSERTN(MPFR_IS_FP(f));
+
+  if (MPFR_IS_ZERO(f))
+    {
+      mpz_set_ui (z, 0);
+      return __mpfr_emin;
+    }
+
+  fn = 1 + (MPFR_PREC(f) - 1) / BITS_PER_MP_LIMB;
+
+  /* check whether allocated space for z is enough */
+  if (ALLOC(z) < fn)
+    MPZ_REALLOC(z, fn);
+
+  sh = (mp_prec_t) fn * BITS_PER_MP_LIMB - MPFR_PREC(f);
+  if (sh)
+    mpn_rshift (PTR(z), MPFR_MANT(f), fn, sh);
+  else
+    MPN_COPY (PTR(z), MPFR_MANT(f), fn);
+
+  SIZ(z) = fn;
+
+  MPFR_ASSERTN((mp_exp_unsigned_t) MPFR_EXP(f) - MPFR_EMIN_MIN
+               >= (mp_exp_unsigned_t) MPFR_PREC(f));
+  return MPFR_EXP(f) - MPFR_PREC(f);
+}