* M_APM - mapmipwr.c
*
* Copyright (C) 1999 - 2007 Michael C. Ring
*
* Permission to use, copy, and distribute this software and its
* documentation for any purpose with or without fee is hereby granted,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation.
*
* Permission to modify the software is granted. Permission to distribute
* the modified code is granted. Modifications are to be distributed by
* using the file 'license.txt' as a template to modify the file header.
* 'license.txt' is available in the official MAPM distribution.
*
* This software is provided "as is" without express or implied warranty.
*/
* $Id: mapmipwr.c,v 1.6 2007/12/03 01:54:39 mike Exp $
*
* This file contains the Integer Power function.
*
* $Log: mapmipwr.c,v $
* Revision 1.6 2007/12/03 01:54:39 mike
* Update license
*
* Revision 1.5 2002/11/03 21:10:32 mike
* Updated function parameters to use the modern style
*
* Revision 1.4 2000/09/23 19:46:04 mike
* change divide call to reciprocal
*
* Revision 1.3 2000/05/24 17:03:35 mike
* return 1 when input is 0^0
*
* Revision 1.2 1999/09/18 01:34:35 mike
* minor tweaks
*
* Revision 1.1 1999/09/18 01:33:09 mike
* Initial revision
*/
#include "m_apm_lc.h"
void m_apm_integer_pow(M_APM rr, int places, M_APM aa, int mexp)
{
M_APM tmp0, tmpy, tmpz;
int nexp, ii, signflag, local_precision;
if (mexp == 0)
{
m_apm_copy(rr, MM_One);
return;
}
else
{
if (mexp > 0)
{
signflag = 0;
nexp = mexp;
}
else
{
signflag = 1;
nexp = -mexp;
}
}
if (aa->m_apm_sign == 0)
{
M_set_to_zero(rr);
return;
}
tmp0 = M_get_stack_var();
tmpy = M_get_stack_var();
tmpz = M_get_stack_var();
local_precision = places + 8;
m_apm_copy(tmpy, MM_One);
m_apm_copy(tmpz, aa);
while (TRUE)
{
ii = nexp & 1;
nexp = nexp >> 1;
if (ii != 0)
{
m_apm_multiply(tmp0, tmpy, tmpz);
m_apm_round(tmpy, local_precision, tmp0);
if (nexp == 0)
break;
}
m_apm_multiply(tmp0, tmpz, tmpz);
m_apm_round(tmpz, local_precision, tmp0);
}
if (signflag)
{
m_apm_reciprocal(rr, places, tmpy);
}
else
{
m_apm_round(rr, places, tmpy);
}
M_restore_stack(3);
}
