| 1 | /* mpf_trunc -- truncate an mpf to an integer. |
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| 2 | |
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| 3 | Copyright 2001 Free Software Foundation, Inc. |
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| 4 | |
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| 5 | This file is part of the GNU MP Library. |
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| 6 | |
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| 7 | The GNU MP Library is free software; you can redistribute it and/or modify |
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| 8 | it under the terms of the GNU Lesser General Public License as published by |
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| 9 | the Free Software Foundation; either version 2.1 of the License, or (at your |
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| 10 | option) any later version. |
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| 11 | |
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| 12 | The GNU MP Library is distributed in the hope that it will be useful, but |
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| 13 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
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| 14 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
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| 15 | License for more details. |
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| 16 | |
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| 17 | You should have received a copy of the GNU Lesser General Public License |
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| 18 | along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
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| 19 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
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| 20 | MA 02111-1307, USA. */ |
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| 21 | |
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| 22 | #include "gmp.h" |
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| 23 | #include "gmp-impl.h" |
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| 24 | |
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| 25 | |
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| 26 | /* Notice the use of prec+1 ensures mpf_trunc is equivalent to mpf_set if u |
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| 27 | is already an integer. */ |
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| 28 | |
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| 29 | void |
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| 30 | mpf_trunc (mpf_ptr r, mpf_srcptr u) |
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| 31 | { |
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| 32 | mp_ptr rp; |
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| 33 | mp_srcptr up; |
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| 34 | mp_size_t size, asize, prec; |
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| 35 | mp_exp_t exp; |
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| 36 | |
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| 37 | exp = EXP(u); |
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| 38 | size = SIZ(u); |
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| 39 | if (size == 0 || exp <= 0) |
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| 40 | { |
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| 41 | /* u is only a fraction */ |
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| 42 | SIZ(r) = 0; |
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| 43 | EXP(r) = 0; |
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| 44 | return; |
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| 45 | } |
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| 46 | |
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| 47 | up = PTR(u); |
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| 48 | EXP(r) = exp; |
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| 49 | asize = ABS (size); |
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| 50 | up += asize; |
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| 51 | |
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| 52 | /* skip fraction part of u */ |
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| 53 | asize = MIN (asize, exp); |
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| 54 | |
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| 55 | /* don't lose precision in the copy */ |
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| 56 | prec = PREC(r) + 1; |
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| 57 | |
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| 58 | /* skip excess over target precision */ |
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| 59 | asize = MIN (asize, prec); |
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| 60 | |
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| 61 | up -= asize; |
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| 62 | rp = PTR(r); |
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| 63 | SIZ(r) = (size >= 0 ? asize : -asize); |
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| 64 | if (rp != up) |
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| 65 | MPN_COPY_INCR (rp, up, asize); |
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| 66 | } |
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