mpir/mpn/generic/subadd_n.c

72 lines
1.8 KiB
C

/* Copyright 2012 The Code cavern
This file is part of the MPIR Library.
The MPIR 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 2.1 of the License, or (at
your option) any later version.
The MPIR 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 MPIR Library; see the file COPYING.LIB. If not, write
to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include "mpir.h"
#include "gmp-impl.h"
//t=x-y-z or t=x-(y+z) which explains the name
mp_limb_t mpn_subadd_n(mp_ptr t,mp_srcptr x,mp_srcptr y,mp_srcptr z,mp_size_t n)
{mp_limb_t ret;
ASSERT(n>0);
ASSERT_MPN(x,n);ASSERT_MPN(y,n);ASSERT_MPN(z,n);//ASSERT_SPACE(t,n);
ASSERT(MPN_SAME_OR_SEPARATE_P(t,x,n));
ASSERT(MPN_SAME_OR_SEPARATE_P(t,y,n));
ASSERT(MPN_SAME_OR_SEPARATE_P(t,z,n));
if(t==x && t==y && t==z)
{
return mpn_neg(t,z,n);
}
if(t==x && t==y)
{ret=mpn_sub_n(t,x,y,n);
ret+=mpn_sub_n(t,t,z,n);
return ret;
}
if(t==x && t==z)
{ret=mpn_sub_n(t,x,z,n);
ret+=mpn_sub_n(t,t,y,n);
return ret;
}
if(t==y && t==z)
{ret=mpn_add_n(t,y,z,n);
ret+=mpn_sub_n(t,x,t,n);// checkcarry
return ret;
}
if(t==x)
{ret=mpn_sub_n(t,x,y,n);
ret+=mpn_sub_n(t,t,z,n);
return ret;
}
if(t==y)
{ret=mpn_sub_n(t,x,y,n);
ret+=mpn_sub_n(t,t,z,n);
return ret;
}
if(t==z)
{ret=mpn_sub_n(t,x,z,n);
ret+=mpn_sub_n(t,t,y,n);
return ret;
}
ret=mpn_sub_n(t,x,z,n);
ret+=mpn_sub_n(t,t,y,n);
return ret;
}