| Index: gcc/gmp/mpf/div_2exp.c
|
| diff --git a/gcc/gmp/mpf/div_2exp.c b/gcc/gmp/mpf/div_2exp.c
|
| deleted file mode 100644
|
| index eea5de3bc88122f2a0020f109542a7bb709260c6..0000000000000000000000000000000000000000
|
| --- a/gcc/gmp/mpf/div_2exp.c
|
| +++ /dev/null
|
| @@ -1,129 +0,0 @@
|
| -/* mpf_div_2exp -- Divide a float by 2^n.
|
| -
|
| -Copyright 1993, 1994, 1996, 2000, 2001, 2002, 2004 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"
|
| -
|
| -
|
| -/* Multiples of GMP_NUMB_BITS in exp simply mean an amount subtracted from
|
| - EXP(u) to set EXP(r). The remainder exp%GMP_NUMB_BITS is then a right
|
| - shift for the limb data.
|
| -
|
| - If exp%GMP_NUMB_BITS == 0 then there's no shifting, we effectively just
|
| - do an mpz_set with changed EXP(r). Like mpz_set we take prec+1 limbs in
|
| - this case. Although just prec would suffice, it's nice to have
|
| - mpf_div_2exp with exp==0 come out the same as mpz_set.
|
| -
|
| - When shifting we take up to prec many limbs from the input. Our shift is
|
| - cy = mpn_rshift (PTR(r)+1, PTR(u)+k, ...), where k is the number of low
|
| - limbs dropped from u, and the carry out is stored to PTR(r)[0]. We don't
|
| - try to work extra bits from PTR(u)[k-1] (when k>=1 makes it available)
|
| - into that low carry limb. Just prec limbs (with the high non-zero) from
|
| - the input is enough bits for the application requested precision, no need
|
| - to do extra work.
|
| -
|
| - If r==u the shift will have overlapping operands. When k>=1 (ie. when
|
| - usize > prec), the overlap is in the style supported by rshift (ie. dst
|
| - <= src).
|
| -
|
| - But when r==u and k==0 (ie. usize <= prec), we would have an invalid
|
| - overlap (mpn_rshift (rp+1, rp, ...)). In this case we must instead use
|
| - mpn_lshift (PTR(r), PTR(u), size, NUMB-shift). An lshift by NUMB-shift
|
| - bits gives identical data of course, it's just its overlap restrictions
|
| - which differ.
|
| -
|
| - In both shift cases, the resulting data is abs_usize+1 limbs. "adj" is
|
| - used to add +1 to that size if the high is non-zero (it may of course
|
| - have become zero by the shifting). EXP(u) is the exponent just above
|
| - those abs_usize+1 limbs, so it gets -1+adj, which means -1 if the high is
|
| - zero, or no change if the high is non-zero.
|
| -
|
| - Enhancements:
|
| -
|
| - The way mpn_lshift is used means successive mpf_div_2exp calls on the
|
| - same operand will accumulate low zero limbs, until prec+1 limbs is
|
| - reached. This is wasteful for subsequent operations. When abs_usize <=
|
| - prec, we should test the low exp%GMP_NUMB_BITS many bits of PTR(u)[0],
|
| - ie. those which would be shifted out by an mpn_rshift. If they're zero
|
| - then use that mpn_rshift. */
|
| -
|
| -void
|
| -mpf_div_2exp (mpf_ptr r, mpf_srcptr u, unsigned long int exp)
|
| -{
|
| - mp_srcptr up;
|
| - mp_ptr rp = r->_mp_d;
|
| - mp_size_t usize;
|
| - mp_size_t abs_usize;
|
| - mp_size_t prec = r->_mp_prec;
|
| - mp_exp_t uexp = u->_mp_exp;
|
| -
|
| - usize = u->_mp_size;
|
| -
|
| - if (UNLIKELY (usize == 0))
|
| - {
|
| - r->_mp_size = 0;
|
| - r->_mp_exp = 0;
|
| - return;
|
| - }
|
| -
|
| - abs_usize = ABS (usize);
|
| - up = u->_mp_d;
|
| -
|
| - if (exp % GMP_NUMB_BITS == 0)
|
| - {
|
| - prec++; /* retain more precision here as we don't need
|
| - to account for carry-out here */
|
| - if (abs_usize > prec)
|
| - {
|
| - up += abs_usize - prec;
|
| - abs_usize = prec;
|
| - }
|
| - if (rp != up)
|
| - MPN_COPY_INCR (rp, up, abs_usize);
|
| - r->_mp_exp = uexp - exp / GMP_NUMB_BITS;
|
| - }
|
| - else
|
| - {
|
| - mp_limb_t cy_limb;
|
| - mp_size_t adj;
|
| - if (abs_usize > prec)
|
| - {
|
| - up += abs_usize - prec;
|
| - abs_usize = prec;
|
| - /* Use mpn_rshift since mpn_lshift operates downwards, and we
|
| - therefore would clobber part of U before using that part, in case
|
| - R is the same variable as U. */
|
| - cy_limb = mpn_rshift (rp + 1, up, abs_usize, exp % GMP_NUMB_BITS);
|
| - rp[0] = cy_limb;
|
| - adj = rp[abs_usize] != 0;
|
| - }
|
| - else
|
| - {
|
| - cy_limb = mpn_lshift (rp, up, abs_usize,
|
| - GMP_NUMB_BITS - exp % GMP_NUMB_BITS);
|
| - rp[abs_usize] = cy_limb;
|
| - adj = cy_limb != 0;
|
| - }
|
| -
|
| - abs_usize += adj;
|
| - r->_mp_exp = uexp - exp / GMP_NUMB_BITS - 1 + adj;
|
| - }
|
| - r->_mp_size = usize >= 0 ? abs_usize : -abs_usize;
|
| -}
|
|
|