version 1.1.1.1, 2000/01/10 15:35:22 |
version 1.1.1.3, 2003/08/25 16:06:35 |
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/* mpf_mul_2exp -- Multiply a float by 2^n. |
/* mpf_mul_2exp -- Multiply a float by 2^n. |
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Copyright (C) 1993, 1994, 1996 Free Software Foundation, Inc. |
Copyright 1993, 1994, 1996, 2000, 2001, 2002 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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The GNU MP Library is free software; you can redistribute it and/or modify |
The GNU MP Library is free software; you can redistribute it and/or modify |
it under the terms of the GNU Library General Public License as published by |
it under the terms of the GNU Lesser General Public License as published by |
the Free Software Foundation; either version 2 of the License, or (at your |
the Free Software Foundation; either version 2.1 of the License, or (at your |
option) any later version. |
option) any later version. |
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The GNU MP Library is distributed in the hope that it will be useful, but |
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 |
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public |
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
License for more details. |
License for more details. |
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You should have received a copy of the GNU Library General Public License |
You should have received a copy of the GNU Lesser General Public License |
along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
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. */ |
Line 23 MA 02111-1307, USA. */ |
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Line 23 MA 02111-1307, USA. */ |
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#include "gmp-impl.h" |
#include "gmp-impl.h" |
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void |
void |
#if __STDC__ |
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mpf_mul_2exp (mpf_ptr r, mpf_srcptr u, unsigned long int exp) |
mpf_mul_2exp (mpf_ptr r, mpf_srcptr u, unsigned long int exp) |
#else |
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mpf_mul_2exp (r, u, exp) |
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mpf_ptr r; |
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mpf_srcptr u; |
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unsigned long int exp; |
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#endif |
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{ |
{ |
mp_srcptr up; |
mp_srcptr up; |
mp_ptr rp = r->_mp_d; |
mp_ptr rp = r->_mp_d; |
Line 51 mpf_mul_2exp (r, u, exp) |
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Line 44 mpf_mul_2exp (r, u, exp) |
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abs_usize = ABS (usize); |
abs_usize = ABS (usize); |
up = u->_mp_d; |
up = u->_mp_d; |
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if (abs_usize > prec) |
if (exp % GMP_NUMB_BITS == 0) |
{ |
{ |
up += abs_usize - prec; |
prec++; /* retain more precision here as we don't need |
abs_usize = prec; |
to account for carry-out here */ |
} |
if (abs_usize > prec) |
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{ |
if (exp % BITS_PER_MP_LIMB == 0) |
up += abs_usize - prec; |
{ |
abs_usize = prec; |
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} |
if (rp != up) |
if (rp != up) |
MPN_COPY (rp, up, abs_usize); |
MPN_COPY_INCR (rp, up, abs_usize); |
r->_mp_size = usize >= 0 ? abs_usize : -abs_usize; |
r->_mp_exp = uexp + exp / GMP_NUMB_BITS; |
r->_mp_exp = uexp + exp / BITS_PER_MP_LIMB; |
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} |
} |
else |
else |
{ |
{ |
mp_limb_t cy_limb; |
mp_limb_t cy_limb; |
if (r != u) |
mp_size_t adj; |
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if (abs_usize > prec) |
{ |
{ |
cy_limb = mpn_lshift (rp, up, abs_usize, exp % BITS_PER_MP_LIMB); |
up += abs_usize - prec; |
rp[abs_usize] = cy_limb; |
abs_usize = prec; |
cy_limb = cy_limb != 0; |
/* Use mpn_rshift since mpn_lshift operates downwards, and we |
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therefore would clobber part of U before using that part, in case |
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R is the same variable as U. */ |
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cy_limb = mpn_rshift (rp + 1, up, abs_usize, |
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GMP_NUMB_BITS - exp % GMP_NUMB_BITS); |
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rp[0] = cy_limb; |
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adj = rp[abs_usize] != 0; |
} |
} |
else |
else |
{ |
{ |
/* Use mpn_rshift since mpn_lshift operates downwards, and we |
cy_limb = mpn_lshift (rp, up, abs_usize, exp % GMP_NUMB_BITS); |
therefore would clobber part of U before using that part. */ |
rp[abs_usize] = cy_limb; |
cy_limb = mpn_rshift (rp + 1, up, abs_usize, -exp % BITS_PER_MP_LIMB); |
adj = cy_limb != 0; |
rp[0] = cy_limb; |
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cy_limb = rp[abs_usize] != 0; |
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} |
} |
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abs_usize += cy_limb; |
abs_usize += adj; |
r->_mp_size = usize >= 0 ? abs_usize : -abs_usize; |
r->_mp_exp = uexp + exp / GMP_NUMB_BITS + adj; |
r->_mp_exp = uexp + exp / BITS_PER_MP_LIMB + cy_limb; |
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} |
} |
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r->_mp_size = usize >= 0 ? abs_usize : -abs_usize; |
} |
} |