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Diffstat (limited to 'gnu/lib/libgmp/mpf/set_q.c')
| -rw-r--r-- | gnu/lib/libgmp/mpf/set_q.c | 170 |
1 files changed, 0 insertions, 170 deletions
diff --git a/gnu/lib/libgmp/mpf/set_q.c b/gnu/lib/libgmp/mpf/set_q.c deleted file mode 100644 index 69d81e3..0000000 --- a/gnu/lib/libgmp/mpf/set_q.c +++ /dev/null @@ -1,170 +0,0 @@ -/* mpf_set_q (mpf_t rop, mpq_t op) -- Convert the rational op to the float rop. - -Copyright (C) 1996 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 Library General Public License as published by -the Free Software Foundation; either version 2 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 Library General Public -License for more details. - -You should have received a copy of the GNU Library General Public License -along with the GNU MP Library; see the file COPYING.LIB. If not, write to -the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, -MA 02111-1307, USA. */ - -#include "gmp.h" -#include "gmp-impl.h" -#include "longlong.h" - -/* Algorithm: - 1. Develop >= n bits of src.num / src.den, where n is the number of bits - in a double. This (partial) division will use all bits from the - denominator. - 2. Use the remainder to determine how to round the result. - 3. Assign the integral result to a temporary double. - 4. Scale the temporary double, and return the result. - - An alternative algorithm, that would be faster: - 0. Let n be somewhat larger than the number of significant bits in a double. - 1. Extract the most significant n bits of the denominator, and an equal - number of bits from the numerator. - 2. Interpret the extracted numbers as integers, call them a and b - respectively, and develop n bits of the fractions ((a + 1) / b) and - (a / (b + 1)) using mpn_divrem. - 3. If the computed values are identical UP TO THE POSITION WE CARE ABOUT, - we are done. If they are different, repeat the algorithm from step 1, - but first let n = n * 2. - 4. If we end up using all bits from the numerator and denominator, fall - back to the first algorithm above. - 5. Just to make life harder, The computation of a + 1 and b + 1 above - might give carry-out... Needs special handling. It might work to - subtract 1 in both cases instead. -*/ - -void -#if __STDC__ -mpf_set_q (mpf_t r, mpq_srcptr q) -#else -mpf_set_q (r, q) - mpf_t r; - mpq_srcptr q; -#endif -{ - mp_ptr np, dp; - mp_ptr rp; - mp_size_t nsize, dsize; - mp_size_t qsize, rsize; - mp_size_t sign_quotient; - unsigned normalization_steps; - mp_limb_t qlimb; - mp_ptr qp; - mp_size_t prec; - mp_exp_t exp; - TMP_DECL (marker); - - nsize = SIZ (&q->_mp_num); - dsize = SIZ (&q->_mp_den); - - if (nsize == 0) - { - SIZ (r) = 0; - EXP (r) = 0; - return; - } - - prec = PREC (r) + 1; - - TMP_MARK (marker); - - qp = PTR (r); - - sign_quotient = nsize ^ dsize; - nsize = ABS (nsize); - dsize = ABS (dsize); - np = PTR (&q->_mp_num); - dp = PTR (&q->_mp_den); - - exp = nsize - dsize; - - if (nsize > prec) - { - np += nsize - prec; - nsize = prec; - } - if (dsize > prec) - { - dp += dsize - prec; - dsize = prec; - } - - rsize = MAX (nsize, dsize); - rp = (mp_ptr) TMP_ALLOC ((rsize + 1) * BYTES_PER_MP_LIMB); - - count_leading_zeros (normalization_steps, dp[dsize - 1]); - - /* Normalize the denominator, i.e. make its most significant bit set by - shifting it NORMALIZATION_STEPS bits to the left. Also shift the - numerator the same number of steps (to keep the quotient the same!). */ - if (normalization_steps != 0) - { - mp_ptr tp; - mp_limb_t nlimb; - - /* Shift up the denominator setting the most significant bit of - the most significant limb. Use temporary storage not to clobber - the original contents of the denominator. */ - tp = (mp_ptr) TMP_ALLOC (dsize * BYTES_PER_MP_LIMB); - mpn_lshift (tp, dp, dsize, normalization_steps); - dp = tp; - - if (rsize != nsize) - { - MPN_ZERO (rp, rsize - nsize); - nlimb = mpn_lshift (rp + (rsize - nsize), - np, nsize, normalization_steps); - } - else - { - nlimb = mpn_lshift (rp, np, nsize, normalization_steps); - } - if (nlimb != 0) - { - rp[rsize] = nlimb; - rsize++; - exp++; - } - } - else - { - if (rsize != nsize) - { - MPN_ZERO (rp, rsize - nsize); - MPN_COPY (rp + (rsize - nsize), np, nsize); - } - else - { - MPN_COPY (rp, np, rsize); - } - } - - qlimb = mpn_divrem (qp, prec - 1 - (rsize - dsize), rp, rsize, dp, dsize); - qsize = prec - 1; - if (qlimb) - { - qp[qsize] = qlimb; - qsize++; - exp++; - } - - EXP (r) = exp; - SIZ (r) = qsize; - - TMP_FREE (marker); -} |
