Imported gcc-4.4.3

[msp430-gcc.git] / mpfr / get_sj.c

diff --git a/mpfr/get_sj.c b/mpfr/get_sj.c
new file mode 100644 (file)
index 0000000..c746fc7
--- /dev/null
+++ b/mpfr/get_sj.c
@@ -0,0 +1,129 @@
+/* mpfr_get_sj -- convert a MPFR number to a huge machine signed integer
+
+Copyright 2004, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+Contributed by the Arenaire and Cacao 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 2.1 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.LIB.  If not, write to
+the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+MA 02110-1301, USA. */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"            /* for a build within gmp */
+#endif
+
+/* The ISO C99 standard specifies that in C++ implementations the
+   INTMAX_MAX, ... macros should only be defined if explicitly requested.  */
+#if defined __cplusplus
+# define __STDC_LIMIT_MACROS
+# define __STDC_CONSTANT_MACROS
+#endif
+
+#if HAVE_INTTYPES_H
+# include <inttypes.h> /* for intmax_t */
+#else
+# if HAVE_STDINT_H
+#  include <stdint.h>
+# endif
+#endif
+
+#include "mpfr-impl.h"
+
+#ifdef _MPFR_H_HAVE_INTMAX_T
+
+intmax_t
+mpfr_get_sj (mpfr_srcptr f, mpfr_rnd_t rnd)
+{
+  intmax_t r;
+  mp_prec_t prec;
+  mpfr_t x;
+
+  if (!mpfr_fits_intmax_p (f, rnd))
+    {
+      MPFR_SET_ERANGE ();
+      return MPFR_IS_NEG (f) ? INTMAX_MIN : INTMAX_MAX;
+    }
+  if (MPFR_IS_ZERO (f))
+     return (intmax_t) 0;
+
+  /* determine the precision of intmax_t */
+  for (r = INTMAX_MIN, prec = 0; r != 0; r /= 2, prec++)
+    {
+    }
+  /* Note: though INTMAX_MAX would have been sufficient for the conversion,
+     we chose INTMAX_MIN so that INTMAX_MIN - 1 is always representable in
+     precision prec; this is useful to detect overflows in GMP_RNDZ (will
+     be needed later). */
+
+  /* Now, r = 0. */
+
+  mpfr_init2 (x, prec);
+  mpfr_rint (x, f, rnd);
+  MPFR_ASSERTN (MPFR_IS_FP (x));
+
+  if (MPFR_NOTZERO (x))
+    {
+      mp_limb_t *xp;
+      int sh, n;        /* An int should be sufficient in this context. */
+
+      xp = MPFR_MANT (x);
+      sh = MPFR_GET_EXP (x);
+      MPFR_ASSERTN ((mp_prec_t) sh <= prec);
+      if (INTMAX_MIN + INTMAX_MAX != 0
+          && MPFR_UNLIKELY ((mp_prec_t) sh == prec))
+        {
+          /* 2's complement and x <= INTMAX_MIN: in the case mp_limb_t
+             has the same size as intmax_t, we cannot use the code in
+             the for loop since the operations would be performed in
+             unsigned arithmetic. */
+          MPFR_ASSERTN (MPFR_IS_NEG (x) && (mpfr_powerof2_raw (x)));
+          r = INTMAX_MIN;
+        }
+      else if (MPFR_IS_POS (x))
+        {
+          for (n = MPFR_LIMB_SIZE (x) - 1; n >= 0; n--)
+            {
+              sh -= BITS_PER_MP_LIMB;
+              /* Note the concerning the casts below:
+                 When sh >= 0, the cast must be performed before the shift
+                 for the case sizeof(intmax_t) > sizeof(mp_limb_t).
+                 When sh < 0, the cast must be performed after the shift
+                 for the case sizeof(intmax_t) == sizeof(mp_limb_t), as
+                 mp_limb_t is unsigned, therefore not representable as an
+                 intmax_t when the MSB is 1 (this is the case here). */
+              r += (sh >= 0
+                    ? (intmax_t) xp[n] << sh
+                    : (intmax_t) (xp[n] >> (-sh)));
+            }
+        }
+      else
+        {
+          for (n = MPFR_LIMB_SIZE (x) - 1; n >= 0; n--)
+            {
+              sh -= BITS_PER_MP_LIMB;
+              /* See above for the note concerning the casts. */
+              r -= (sh >= 0
+                    ? (intmax_t) xp[n] << sh
+                    : (intmax_t) (xp[n] >> (-sh)));
+            }
+        }
+    }
+
+  mpfr_clear (x);
+
+  return r;
+}
+
+#endif