--- /dev/null
+/* mpfr_set_z -- set a floating-point number from a multiple-precision integer
+
+Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 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. */
+
+#define MPFR_NEED_LONGLONG_H
+#include "mpfr-impl.h"
+
+/* set f to the integer z */
+int
+mpfr_set_z (mpfr_ptr f, mpz_srcptr z, mp_rnd_t rnd_mode)
+{
+ mp_size_t fn, zn, dif;
+ int k, sign_z, inex;
+ mp_limb_t *fp, *zp;
+ mp_exp_t exp;
+
+ sign_z = mpz_sgn (z);
+ if (MPFR_UNLIKELY (sign_z == 0))
+ {
+ MPFR_SET_ZERO(f);
+ MPFR_SET_POS(f);
+ MPFR_RET(0);
+ }
+ MPFR_ASSERTD (sign_z == MPFR_SIGN_POS || sign_z == MPFR_SIGN_NEG);
+
+ zn = ABS(SIZ(z));
+ MPFR_ASSERTD (zn >= 1);
+ if (MPFR_UNLIKELY (zn > MPFR_EMAX_MAX / BITS_PER_MP_LIMB + 1))
+ return mpfr_overflow (f, rnd_mode, sign_z);
+
+ fp = MPFR_MANT (f);
+ fn = MPFR_LIMB_SIZE (f);
+ dif = zn - fn;
+ zp = PTR(z);
+ count_leading_zeros (k, zp[zn-1]);
+ /* because zn >= __gmpfr_emax / BITS_PER_MP_LIMB + 2
+ and zn * BITS_PER_MP_LIMB >= __gmpfr_emax + BITS_PER_MP_LIMB + 1
+ and exp = zn * BITS_PER_MP_LIMB - k > __gmpfr_emax */
+
+ /* now zn <= MPFR_EMAX_MAX / BITS_PER_MP_LIMB + 1
+ thus zn * BITS_PER_MP_LIMB <= MPFR_EMAX_MAX + BITS_PER_MP_LIMB
+ and exp = zn * BITS_PER_MP_LIMB - k
+ <= MPFR_EMAX_MAX + BITS_PER_MP_LIMB */
+ exp = (mp_prec_t) zn * BITS_PER_MP_LIMB - k;
+ /* The exponent will be exp or exp + 1 (due to rounding) */
+ if (MPFR_UNLIKELY (exp > __gmpfr_emax))
+ return mpfr_overflow (f, rnd_mode, sign_z);
+ if (MPFR_UNLIKELY (exp + 1 < __gmpfr_emin))
+ return mpfr_underflow(f, rnd_mode == GMP_RNDN ? GMP_RNDZ : rnd_mode,
+ sign_z);
+
+ if (MPFR_LIKELY (dif >= 0))
+ {
+ mp_limb_t rb, sb, ulp;
+ int sh;
+
+ /* number has to be truncated */
+ if (MPFR_LIKELY (k != 0))
+ {
+ mpn_lshift (fp, &zp[dif], fn, k);
+ if (MPFR_LIKELY (dif > 0))
+ fp[0] |= zp[dif - 1] >> (BITS_PER_MP_LIMB - k);
+ }
+ else
+ MPN_COPY (fp, zp + dif, fn);
+
+ /* Compute Rounding Bit and Sticky Bit */
+ MPFR_UNSIGNED_MINUS_MODULO (sh, MPFR_PREC (f) );
+ if (MPFR_LIKELY (sh != 0))
+ {
+ mp_limb_t mask = MPFR_LIMB_ONE << (sh-1);
+ mp_limb_t limb = fp[0];
+ rb = limb & mask;
+ sb = limb & (mask-1);
+ ulp = 2*mask;
+ fp[0] = limb & ~(ulp-1);
+ }
+ else /* sh == 0 */
+ {
+ mp_limb_t mask = MPFR_LIMB_ONE << (BITS_PER_MP_LIMB - 1 - k);
+ if (MPFR_LIKELY (dif > 0))
+ {
+ rb = zp[--dif] & mask;
+ sb = zp[dif] & (mask-1);
+ }
+ else
+ rb = sb = 0;
+ k = 0;
+ ulp = MPFR_LIMB_ONE;
+ }
+ if (MPFR_UNLIKELY (sb == 0) && MPFR_LIKELY (dif > 0))
+ {
+ sb = zp[--dif];
+ if (MPFR_LIKELY (k != 0))
+ sb &= MPFR_LIMB_MASK (BITS_PER_MP_LIMB - k);
+ if (MPFR_UNLIKELY (sb == 0) && MPFR_LIKELY (dif > 0))
+ do {
+ sb = zp[--dif];
+ } while (dif > 0 && sb == 0);
+ }
+
+ /* Rounding */
+ if (MPFR_LIKELY (rnd_mode == GMP_RNDN))
+ {
+ if (rb == 0 || MPFR_UNLIKELY (sb == 0 && (fp[0] & ulp) == 0))
+ goto trunc;
+ else
+ goto addoneulp;
+ }
+ else /* Not Nearest */
+ {
+ if (MPFR_LIKELY (MPFR_IS_LIKE_RNDZ (rnd_mode, sign_z < 0))
+ || MPFR_UNLIKELY ( (sb|rb) == 0 ))
+ goto trunc;
+ else
+ goto addoneulp;
+ }
+
+ trunc:
+ inex = MPFR_LIKELY ((sb | rb) != 0) ? -1 : 0;
+ goto end;
+
+ addoneulp:
+ inex = 1;
+ if (MPFR_UNLIKELY (mpn_add_1 (fp, fp, fn, ulp)))
+ {
+ /* Pow 2 case */
+ if (MPFR_UNLIKELY (exp == __gmpfr_emax))
+ return mpfr_overflow (f, rnd_mode, sign_z);
+ exp ++;
+ fp[fn-1] = MPFR_LIMB_HIGHBIT;
+ }
+ end:
+ (void) 0;
+ }
+ else /* dif < 0: Mantissa F is strictly bigger than z's one */
+ {
+ if (MPFR_LIKELY (k != 0))
+ mpn_lshift (fp - dif, zp, zn, k);
+ else
+ MPN_COPY (fp - dif, zp, zn);
+ /* fill with zeroes */
+ MPN_ZERO (fp, -dif);
+ inex = 0; /* result is exact */
+ }
+
+ if (MPFR_UNLIKELY (exp < __gmpfr_emin))
+ {
+ if (rnd_mode == GMP_RNDN && inex == 0 && mpfr_powerof2_raw (f))
+ rnd_mode = GMP_RNDZ;
+ return mpfr_underflow(f, rnd_mode, sign_z);
+ }
+
+ MPFR_SET_EXP (f, exp);
+ MPFR_SET_SIGN (f, sign_z);
+ MPFR_RET (inex*sign_z);
+}
+
projects / msp430-gcc.git / blobdiff