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/*
* fixpoint.c - Fixed point routines.
*
* Written by
* Andreas Dehmel <dehmel@forwiss.tu-muenchen.de>
*
* This file is part of VICE, the Versatile Commodore Emulator.
* See README for copyright notice.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307 USA.
*
*/
#ifndef _FIXPOINT_C
#define _FIXPOINT_C
#ifdef _FIXPOINT_H
#define FIXPOINT_FROM_HEADER
#endif
#include "fixpoint.h"
#ifdef FIXPOINT_ARITHMETIC
#ifdef INLINE_FIXPOINT_FUNCTIONS
#define FUNC_INLINE_STATEMENT static inline
#else
#define FUNC_INLINE_STATEMENT
#endif
/* Only make the function(s) visible if no inlining or inlining _and_ we're
* not compiling fixpoint.c */
#if (!defined(INLINE_FIXPOINT_FUNCTIONS) || (defined(INLINE_FIXPOINT_FUNCTIONS) && defined(FIXPOINT_FROM_HEADER)))
FUNC_INLINE_STATEMENT vreal_t fixpoint_mult(vreal_t x, vreal_t y)
{
unsigned int a, b, c, d;
int sign = ((x ^ y) < 0) ? 1 : 0;
if (x < 0) x *= -1;
if (y < 0) y *= -1;
a = (((unsigned int) x) >> FIXPOINT_PREC);
b = ( (unsigned int) x) & ~(a << FIXPOINT_PREC);
c = (((unsigned int) y) >> FIXPOINT_PREC);
d = ( (unsigned int) y) & ~(c << FIXPOINT_PREC);
a = (((a * c) << FIXPOINT_PREC)
+ (a * d + b * c)
+ (((b * d) + (1 << (FIXPOINT_PREC - 1))) >> FIXPOINT_PREC));
return sign ? -a : a;
}
FUNC_INLINE_STATEMENT soundclk_t soundclk_mult(soundclk_t a, soundclk_t b)
{
unsigned long ia, ib, fa, fb;
ia = (a>>SOUNDCLK_PREC); fa = a & ((1<<SOUNDCLK_PREC)-1);
ib = (b>>SOUNDCLK_PREC); fb = b & ((1<<SOUNDCLK_PREC)-1);
return (((ia*ib)<<SOUNDCLK_PREC) + (ia*fb+ib*fa) + ((fa*fb)>>SOUNDCLK_PREC));
}
#endif
#endif
#endif
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