--- /dev/null
+/* __gmp_extract_double -- convert from double to array of mp_limb_t.
+
+Copyright 1996, 1999, 2000, 2001, 2002, 2006 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"
+
+#ifdef XDEBUG
+#undef _GMP_IEEE_FLOATS
+#endif
+
+#ifndef _GMP_IEEE_FLOATS
+#define _GMP_IEEE_FLOATS 0
+#endif
+
+#define BITS_IN_MANTISSA 53
+
+/* Extract a non-negative double in d. */
+
+int
+__gmp_extract_double (mp_ptr rp, double d)
+{
+ long exp;
+ unsigned sc;
+#ifdef _LONG_LONG_LIMB
+#define BITS_PER_PART 64 /* somewhat bogus */
+ unsigned long long int manl;
+#else
+#define BITS_PER_PART GMP_LIMB_BITS
+ unsigned long int manh, manl;
+#endif
+
+ /* BUGS
+
+ 1. Should handle Inf and NaN in IEEE specific code.
+ 2. Handle Inf and NaN also in default code, to avoid hangs.
+ 3. Generalize to handle all GMP_LIMB_BITS >= 32.
+ 4. This lits is incomplete and misspelled.
+ */
+
+ ASSERT (d >= 0.0);
+
+ if (d == 0.0)
+ {
+ MPN_ZERO (rp, LIMBS_PER_DOUBLE);
+ return 0;
+ }
+
+#if _GMP_IEEE_FLOATS
+ {
+#if defined (__alpha) && __GNUC__ == 2 && __GNUC_MINOR__ == 8
+ /* Work around alpha-specific bug in GCC 2.8.x. */
+ volatile
+#endif
+ union ieee_double_extract x;
+ x.d = d;
+ exp = x.s.exp;
+#if BITS_PER_PART == 64 /* generalize this to BITS_PER_PART > BITS_IN_MANTISSA */
+ manl = (((mp_limb_t) 1 << 63)
+ | ((mp_limb_t) x.s.manh << 43) | ((mp_limb_t) x.s.manl << 11));
+ if (exp == 0)
+ {
+ /* Denormalized number. Don't try to be clever about this,
+ since it is not an important case to make fast. */
+ exp = 1;
+ do
+ {
+ manl = manl << 1;
+ exp--;
+ }
+ while ((manl & GMP_LIMB_HIGHBIT) == 0);
+ }
+#endif
+#if BITS_PER_PART == 32
+ manh = ((mp_limb_t) 1 << 31) | (x.s.manh << 11) | (x.s.manl >> 21);
+ manl = x.s.manl << 11;
+ if (exp == 0)
+ {
+ /* Denormalized number. Don't try to be clever about this,
+ since it is not an important case to make fast. */
+ exp = 1;
+ do
+ {
+ manh = (manh << 1) | (manl >> 31);
+ manl = manl << 1;
+ exp--;
+ }
+ while ((manh & GMP_LIMB_HIGHBIT) == 0);
+ }
+#endif
+#if BITS_PER_PART != 32 && BITS_PER_PART != 64
+ You need to generalize the code above to handle this.
+#endif
+ exp -= 1022; /* Remove IEEE bias. */
+ }
+#else
+ {
+ /* Unknown (or known to be non-IEEE) double format. */
+ exp = 0;
+ if (d >= 1.0)
+ {
+ ASSERT_ALWAYS (d * 0.5 != d);
+
+ while (d >= 32768.0)
+ {
+ d *= (1.0 / 65536.0);
+ exp += 16;
+ }
+ while (d >= 1.0)
+ {
+ d *= 0.5;
+ exp += 1;
+ }
+ }
+ else if (d < 0.5)
+ {
+ while (d < (1.0 / 65536.0))
+ {
+ d *= 65536.0;
+ exp -= 16;
+ }
+ while (d < 0.5)
+ {
+ d *= 2.0;
+ exp -= 1;
+ }
+ }
+
+ d *= (4.0 * ((unsigned long int) 1 << (BITS_PER_PART - 2)));
+#if BITS_PER_PART == 64
+ manl = d;
+#endif
+#if BITS_PER_PART == 32
+ manh = d;
+ manl = (d - manh) * (4.0 * ((unsigned long int) 1 << (BITS_PER_PART - 2)));
+#endif
+ }
+#endif /* IEEE */
+
+ sc = (unsigned) (exp + 64 * GMP_NUMB_BITS) % GMP_NUMB_BITS;
+
+ /* We add something here to get rounding right. */
+ exp = (exp + 64 * GMP_NUMB_BITS) / GMP_NUMB_BITS - 64 * GMP_NUMB_BITS / GMP_NUMB_BITS + 1;
+
+#if BITS_PER_PART == 64 && LIMBS_PER_DOUBLE == 2
+#if GMP_NAIL_BITS == 0
+ if (sc != 0)
+ {
+ rp[1] = manl >> (GMP_LIMB_BITS - sc);
+ rp[0] = manl << sc;
+ }
+ else
+ {
+ rp[1] = manl;
+ rp[0] = 0;
+ exp--;
+ }
+#else
+ if (sc > GMP_NAIL_BITS)
+ {
+ rp[1] = manl >> (GMP_LIMB_BITS - sc);
+ rp[0] = (manl << (sc - GMP_NAIL_BITS)) & GMP_NUMB_MASK;
+ }
+ else
+ {
+ if (sc == 0)
+ {
+ rp[1] = manl >> GMP_NAIL_BITS;
+ rp[0] = (manl << GMP_NUMB_BITS - GMP_NAIL_BITS) & GMP_NUMB_MASK;
+ exp--;
+ }
+ else
+ {
+ rp[1] = manl >> (GMP_LIMB_BITS - sc);
+ rp[0] = (manl >> (GMP_NAIL_BITS - sc)) & GMP_NUMB_MASK;
+ }
+ }
+#endif
+#endif
+
+#if BITS_PER_PART == 64 && LIMBS_PER_DOUBLE == 3
+ if (sc > GMP_NAIL_BITS)
+ {
+ rp[2] = manl >> (GMP_LIMB_BITS - sc);
+ rp[1] = (manl << sc - GMP_NAIL_BITS) & GMP_NUMB_MASK;
+ if (sc >= 2 * GMP_NAIL_BITS)
+ rp[0] = 0;
+ else
+ rp[0] = (manl << GMP_NUMB_BITS - GMP_NAIL_BITS + sc) & GMP_NUMB_MASK;
+ }
+ else
+ {
+ if (sc == 0)
+ {
+ rp[2] = manl >> GMP_NAIL_BITS;
+ rp[1] = (manl << GMP_NUMB_BITS - GMP_NAIL_BITS) & GMP_NUMB_MASK;
+ rp[0] = 0;
+ exp--;
+ }
+ else
+ {
+ rp[2] = manl >> (GMP_LIMB_BITS - sc);
+ rp[1] = (manl >> GMP_NAIL_BITS - sc) & GMP_NUMB_MASK;
+ rp[0] = (manl << GMP_NUMB_BITS - GMP_NAIL_BITS + sc) & GMP_NUMB_MASK;
+ }
+ }
+#endif
+
+#if BITS_PER_PART == 32 && LIMBS_PER_DOUBLE == 3
+#if GMP_NAIL_BITS == 0
+ if (sc != 0)
+ {
+ rp[2] = manh >> (GMP_LIMB_BITS - sc);
+ rp[1] = (manh << sc) | (manl >> (GMP_LIMB_BITS - sc));
+ rp[0] = manl << sc;
+ }
+ else
+ {
+ rp[2] = manh;
+ rp[1] = manl;
+ rp[0] = 0;
+ exp--;
+ }
+#else
+ if (sc > GMP_NAIL_BITS)
+ {
+ rp[2] = (manh >> (GMP_LIMB_BITS - sc));
+ rp[1] = ((manh << (sc - GMP_NAIL_BITS)) |
+ (manl >> (GMP_LIMB_BITS - sc + GMP_NAIL_BITS))) & GMP_NUMB_MASK;
+ if (sc >= 2 * GMP_NAIL_BITS)
+ rp[0] = (manl << sc - 2 * GMP_NAIL_BITS) & GMP_NUMB_MASK;
+ else
+ rp[0] = manl >> (2 * GMP_NAIL_BITS - sc) & GMP_NUMB_MASK;
+ }
+ else
+ {
+ if (sc == 0)
+ {
+ rp[2] = manh >> GMP_NAIL_BITS;
+ rp[1] = ((manh << GMP_NUMB_BITS - GMP_NAIL_BITS) | (manl >> 2 * GMP_NAIL_BITS)) & GMP_NUMB_MASK;
+ rp[0] = (manl << GMP_NUMB_BITS - 2 * GMP_NAIL_BITS) & GMP_NUMB_MASK;
+ exp--;
+ }
+ else
+ {
+ rp[2] = (manh >> (GMP_LIMB_BITS - sc));
+ rp[1] = (manh >> (GMP_NAIL_BITS - sc)) & GMP_NUMB_MASK;
+ rp[0] = ((manh << (GMP_NUMB_BITS - GMP_NAIL_BITS + sc))
+ | (manl >> (GMP_LIMB_BITS - (GMP_NUMB_BITS - GMP_NAIL_BITS + sc)))) & GMP_NUMB_MASK;
+ }
+ }
+#endif
+#endif
+
+#if BITS_PER_PART == 32 && LIMBS_PER_DOUBLE > 3
+ if (sc == 0)
+ {
+ int i;
+
+ for (i = LIMBS_PER_DOUBLE - 1; i >= 0; i--)
+ {
+ rp[i] = manh >> (BITS_PER_ULONG - GMP_NUMB_BITS);
+ manh = ((manh << GMP_NUMB_BITS)
+ | (manl >> (BITS_PER_ULONG - GMP_NUMB_BITS)));
+ manl = manl << GMP_NUMB_BITS;
+ }
+ exp--;
+ }
+ else
+ {
+ int i;
+
+ rp[LIMBS_PER_DOUBLE - 1] = (manh >> (GMP_LIMB_BITS - sc));
+ manh = (manh << sc) | (manl >> (GMP_LIMB_BITS - sc));
+ manl = (manl << sc);
+ for (i = LIMBS_PER_DOUBLE - 2; i >= 0; i--)
+ {
+ rp[i] = manh >> (BITS_PER_ULONG - GMP_NUMB_BITS);
+ manh = ((manh << GMP_NUMB_BITS)
+ | (manl >> (BITS_PER_ULONG - GMP_NUMB_BITS)));
+ manl = manl << GMP_NUMB_BITS;
+ }
+ }
+#endif
+
+ return exp;
+}
projects / msp430-gcc.git / blobdiff