| /* mpz_add_ui, mpz_sub_ui -- Add or subtract an mpz_t and an unsigned |
| one-word integer. |
| |
| Copyright 1991, 1993, 1994, 1996, 1999, 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" |
| |
| |
| #ifdef OPERATION_add_ui |
| #define FUNCTION mpz_add_ui |
| #define FUNCTION2 mpz_add |
| #define VARIATION_CMP >= |
| #define VARIATION_NEG |
| #define VARIATION_UNNEG - |
| #endif |
| |
| #ifdef OPERATION_sub_ui |
| #define FUNCTION mpz_sub_ui |
| #define FUNCTION2 mpz_sub |
| #define VARIATION_CMP < |
| #define VARIATION_NEG - |
| #define VARIATION_UNNEG |
| #endif |
| |
| #ifndef FUNCTION |
| Error, need OPERATION_add_ui or OPERATION_sub_ui |
| #endif |
| |
| |
| void |
| FUNCTION (mpz_ptr w, mpz_srcptr u, unsigned long int vval) |
| { |
| mp_srcptr up; |
| mp_ptr wp; |
| mp_size_t usize, wsize; |
| mp_size_t abs_usize; |
| |
| #if BITS_PER_ULONG > GMP_NUMB_BITS /* avoid warnings about shift amount */ |
| if (vval > GMP_NUMB_MAX) |
| { |
| mpz_t v; |
| mp_limb_t vl[2]; |
| PTR(v) = vl; |
| vl[0] = vval & GMP_NUMB_MASK; |
| vl[1] = vval >> GMP_NUMB_BITS; |
| SIZ(v) = 2; |
| FUNCTION2 (w, u, v); |
| return; |
| } |
| #endif |
| |
| usize = u->_mp_size; |
| abs_usize = ABS (usize); |
| |
| /* If not space for W (and possible carry), increase space. */ |
| wsize = abs_usize + 1; |
| if (w->_mp_alloc < wsize) |
| _mpz_realloc (w, wsize); |
| |
| /* These must be after realloc (U may be the same as W). */ |
| up = u->_mp_d; |
| wp = w->_mp_d; |
| |
| if (abs_usize == 0) |
| { |
| wp[0] = vval; |
| w->_mp_size = VARIATION_NEG (vval != 0); |
| return; |
| } |
| |
| if (usize VARIATION_CMP 0) |
| { |
| mp_limb_t cy; |
| cy = mpn_add_1 (wp, up, abs_usize, (mp_limb_t) vval); |
| wp[abs_usize] = cy; |
| wsize = VARIATION_NEG (abs_usize + cy); |
| } |
| else |
| { |
| /* The signs are different. Need exact comparison to determine |
| which operand to subtract from which. */ |
| if (abs_usize == 1 && up[0] < vval) |
| { |
| wp[0] = vval - up[0]; |
| wsize = VARIATION_NEG 1; |
| } |
| else |
| { |
| mpn_sub_1 (wp, up, abs_usize, (mp_limb_t) vval); |
| /* Size can decrease with at most one limb. */ |
| wsize = VARIATION_UNNEG (abs_usize - (wp[abs_usize - 1] == 0)); |
| } |
| } |
| |
| w->_mp_size = wsize; |
| } |