diff options
Diffstat (limited to 'vendor/gmp-6.3.0/mpz/ui_sub.c')
-rw-r--r-- | vendor/gmp-6.3.0/mpz/ui_sub.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/vendor/gmp-6.3.0/mpz/ui_sub.c b/vendor/gmp-6.3.0/mpz/ui_sub.c new file mode 100644 index 0000000..1d0edb9 --- /dev/null +++ b/vendor/gmp-6.3.0/mpz/ui_sub.c @@ -0,0 +1,90 @@ +/* mpz_ui_sub -- Subtract an unsigned one-word integer and an mpz_t. + +Copyright 2002, 2004, 2015 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" + +void +mpz_ui_sub (mpz_ptr w, unsigned long int uval, mpz_srcptr v) +{ + mp_ptr vp, wp; + mp_size_t vn, wn; + mp_limb_t cy; + +#if BITS_PER_ULONG > GMP_NUMB_BITS /* avoid warnings about shift amount */ + if (uval > GMP_NUMB_MAX) + { + mpz_t u; + mp_limb_t ul[2]; + PTR(u) = ul; + ul[0] = uval & GMP_NUMB_MASK; + ul[1] = uval >> GMP_NUMB_BITS; + SIZ(u) = 2; + mpz_sub (w, u, v); + return; + } +#endif + + vn = SIZ(v); + + if (vn > 1) + { + wp = MPZ_REALLOC (w, vn); + vp = PTR(v); + mpn_sub_1 (wp, vp, vn, (mp_limb_t) uval); + wn = -(vn - (wp[vn - 1] == 0)); + } + else if (vn >= 0) + { + mp_limb_t vp0; + vp0 = PTR (v)[0] & - (mp_limb_t) vn; + wp = MPZ_NEWALLOC (w, 1); + if (uval >= vp0) + { + wp[0] = uval - vp0; + wn = wp[0] != 0; + } + else + { + wp[0] = vp0 - uval; + wn = -1; + } + } + else /* (vn < 0) */ + { + vn = -vn; + wp = MPZ_REALLOC (w, vn + 1); + vp = PTR(v); + cy = mpn_add_1 (wp, vp, vn, (mp_limb_t) uval); + wp[vn] = cy; + wn = vn + (cy != 0); + } + + SIZ(w) = wn; +} |