version 1.1.1.2, 2000/09/09 14:12:58 |
version 1.1.1.3, 2003/08/25 16:06:34 |
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/* mpz_sub -- Subtract two integers. |
/* mpz_sub -- subtract integers. |
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Copyright (C) 1991, 1993, 1994, 1996, 2000 Free Software Foundation, Inc. |
Copyright 2001 Free Software Foundation, Inc. |
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This file is part of the GNU MP Library. |
This file is part of the GNU MP Library. |
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Line 19 along with the GNU MP Library; see the file COPYING.LI |
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Line 19 along with the GNU MP Library; see the file COPYING.LI |
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the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
MA 02111-1307, USA. */ |
MA 02111-1307, USA. */ |
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#include "gmp.h" |
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#include "gmp-impl.h" |
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#ifdef BERKELEY_MP |
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#include "mp.h" |
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#endif |
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#ifndef BERKELEY_MP |
#define OPERATION_sub |
void |
#include "aors.h" |
#if __STDC__ |
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mpz_sub (mpz_ptr w, mpz_srcptr u, mpz_srcptr v) |
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#else |
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mpz_sub (w, u, v) |
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mpz_ptr w; |
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mpz_srcptr u; |
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mpz_srcptr v; |
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#endif |
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#else /* BERKELEY_MP */ |
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void |
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#if __STDC__ |
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msub (mpz_srcptr u, mpz_srcptr v, mpz_ptr w) |
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#else |
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msub (u, v, w) |
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mpz_srcptr u; |
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mpz_srcptr v; |
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mpz_ptr w; |
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#endif |
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#endif /* BERKELEY_MP */ |
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{ |
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mp_srcptr up, vp; |
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mp_ptr wp; |
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mp_size_t usize, vsize, wsize; |
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mp_size_t abs_usize; |
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mp_size_t abs_vsize; |
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usize = u->_mp_size; |
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vsize = -v->_mp_size; /* The "-" makes the difference from mpz_add */ |
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abs_usize = ABS (usize); |
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abs_vsize = ABS (vsize); |
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if (abs_usize < abs_vsize) |
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{ |
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/* Swap U and V. */ |
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MPZ_SRCPTR_SWAP (u, v); |
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MP_SIZE_T_SWAP (usize, vsize); |
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MP_SIZE_T_SWAP (abs_usize, abs_vsize); |
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} |
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/* True: ABS_USIZE >= ABS_VSIZE. */ |
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/* If not space for w (and possible carry), increase space. */ |
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wsize = abs_usize + 1; |
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if (w->_mp_alloc < wsize) |
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_mpz_realloc (w, wsize); |
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/* These must be after realloc (u or v may be the same as w). */ |
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up = u->_mp_d; |
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vp = v->_mp_d; |
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wp = w->_mp_d; |
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if ((usize ^ vsize) < 0) |
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{ |
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/* U and V have different sign. Need to compare them to determine |
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which operand to subtract from which. */ |
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/* This test is right since ABS_USIZE >= ABS_VSIZE. */ |
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if (abs_usize != abs_vsize) |
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{ |
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mpn_sub (wp, up, abs_usize, vp, abs_vsize); |
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wsize = abs_usize; |
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MPN_NORMALIZE (wp, wsize); |
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if (usize < 0) |
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wsize = -wsize; |
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} |
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else if (mpn_cmp (up, vp, abs_usize) < 0) |
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{ |
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mpn_sub_n (wp, vp, up, abs_usize); |
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wsize = abs_usize; |
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MPN_NORMALIZE (wp, wsize); |
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if (usize >= 0) |
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wsize = -wsize; |
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} |
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else |
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{ |
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mpn_sub_n (wp, up, vp, abs_usize); |
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wsize = abs_usize; |
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MPN_NORMALIZE (wp, wsize); |
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if (usize < 0) |
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wsize = -wsize; |
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} |
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} |
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else |
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{ |
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/* U and V have same sign. Add them. */ |
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mp_limb_t cy_limb = mpn_add (wp, up, abs_usize, vp, abs_vsize); |
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wp[abs_usize] = cy_limb; |
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wsize = abs_usize + cy_limb; |
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if (usize < 0) |
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wsize = -wsize; |
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} |
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w->_mp_size = wsize; |
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} |
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