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; |
-} |