diff options
Diffstat (limited to 'vendor/gmp-6.3.0/mpf/get_si.c')
-rw-r--r-- | vendor/gmp-6.3.0/mpf/get_si.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/vendor/gmp-6.3.0/mpf/get_si.c b/vendor/gmp-6.3.0/mpf/get_si.c new file mode 100644 index 0000000..6ac4d44 --- /dev/null +++ b/vendor/gmp-6.3.0/mpf/get_si.c @@ -0,0 +1,86 @@ +/* mpf_get_si -- mpf to long conversion + +Copyright 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 either: + + * 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. + +or + + * the GNU General Public License as published by the Free Software + Foundation; either version 2 of the License, or (at your option) any + later version. + +or both in parallel, as here. + +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 General Public License +for more details. + +You should have received copies of the GNU General Public License and the +GNU Lesser General Public License along with the GNU MP Library. If not, +see https://www.gnu.org/licenses/. */ + +#include "gmp-impl.h" + + +/* Any fraction bits are truncated, meaning simply discarded. + + For values bigger than a long, the low bits are returned, like + mpz_get_si, but this isn't documented. + + Notice this is equivalent to mpz_set_f + mpz_get_si. + + + Implementation: + + fl is established in basically the same way as for mpf_get_ui, see that + code for explanations of the conditions. + + However unlike mpf_get_ui we need an explicit return 0 for exp<=0. When + f is a negative fraction (ie. size<0 and exp<=0) we can't let fl==0 go + through to the zany final "~ ((fl - 1) & LONG_MAX)", that would give + -0x80000000 instead of the desired 0. */ + +long +mpf_get_si (mpf_srcptr f) __GMP_NOTHROW +{ + mp_exp_t exp; + mp_size_t size, abs_size; + mp_srcptr fp; + mp_limb_t fl; + + exp = EXP (f); + size = SIZ (f); + fp = PTR (f); + + /* fraction alone truncates to zero + this also covers zero, since we have exp==0 for zero */ + if (exp <= 0) + return 0L; + + /* there are some limbs above the radix point */ + + fl = 0; + abs_size = ABS (size); + if (abs_size >= exp) + fl = fp[abs_size-exp]; + +#if BITS_PER_ULONG > GMP_NUMB_BITS + if (exp > 1 && abs_size+1 >= exp) + fl |= fp[abs_size - exp + 1] << GMP_NUMB_BITS; +#endif + + if (size > 0) + return fl & LONG_MAX; + else + /* this form necessary to correctly handle -0x80..00 */ + return -1 - (long) ((fl - 1) & LONG_MAX); +} |