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/* Emacs style mode select -*- C++ -*-
*-----------------------------------------------------------------------------
*
*
* PrBoom: a Doom port merged with LxDoom and LSDLDoom
* based on BOOM, a modified and improved DOOM engine
* Copyright (C) 1999 by
* id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
* Copyright (C) 1999-2000 by
* Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
* Copyright 2005, 2006 by
* Florian Schulze, Colin Phipps, Neil Stevens, Andrey Budko
*
* 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.
*
* DESCRIPTION:
* Fixed point arithemtics, implementation.
*
*-----------------------------------------------------------------------------*/
#ifndef __M_FIXED__
#define __M_FIXED__
#include "config.h"
#include "doomtype.h"
/*
* Fixed point, 32bit as 16.16.
*/
#define FRACBITS 16
#define FRACUNIT (1<<FRACBITS)
typedef int fixed_t;
/*
* Absolute Value
*
* killough 5/10/98: In djgpp, use inlined assembly for performance
* killough 9/05/98: better code seems to be gotten from using inlined C
*/
inline static const int D_abs(int x)
{
fixed_t _t = (x),_s;
_s = _t >> (8*sizeof _t-1);
return (_t^_s)-_s;
}
/*
* Fixed Point Multiplication
*/
/* CPhipps - made __inline__ to inline, as specified in the gcc docs
* Also made const */
inline static CONSTFUNC fixed_t FixedMul(fixed_t a, fixed_t b)
{
return (fixed_t)((int_64_t) a*b >> FRACBITS);
}
/*
* Fixed Point Division
*/
/* CPhipps - made __inline__ to inline, as specified in the gcc docs
* Also made const */
inline static CONSTFUNC fixed_t FixedDiv(fixed_t a, fixed_t b)
{
return ((unsigned)D_abs(a)>>14) >= (unsigned)D_abs(b) ? ((a^b)>>31) ^ INT_MAX :
(fixed_t)(((int_64_t) a << FRACBITS) / b);
}
/* CPhipps -
* FixedMod - returns a % b, guaranteeing 0<=a<b
* (notice that the C standard for % does not guarantee this)
*/
inline static CONSTFUNC fixed_t FixedMod(fixed_t a, fixed_t b)
{
if (b & (b-1)) {
fixed_t r = a % b;
return ((r<0) ? r+b : r);
} else
return (a & (b-1));
}
#endif
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