mirror of
https://github.com/ZDoom/gzdoom.git
synced 2025-04-29 14:01:02 +00:00
104 lines
2 KiB
C
104 lines
2 KiB
C
|
// Emacs style mode select -*- C++ -*-
|
||
|
|
//-----------------------------------------------------------------------------
|
||
|
|
//
|
||
|
|
// $Id:$
|
||
|
|
//
|
||
|
|
// Copyright (C) 1993-1996 by id Software, Inc.
|
||
|
|
//
|
||
|
|
// This source is available for distribution and/or modification
|
||
|
|
// only under the terms of the DOOM Source Code License as
|
||
|
|
// published by id Software. All rights reserved.
|
||
|
|
//
|
||
|
|
// The source is distributed in the hope that it will be useful,
|
||
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
|
||
|
|
// for more details.
|
||
|
|
//
|
||
|
|
// $Log:$
|
||
|
|
//
|
||
|
|
// DESCRIPTION:
|
||
|
|
// Fixed point implementation.
|
||
|
|
//
|
||
|
|
//-----------------------------------------------------------------------------
|
||
|
|
|
||
|
|
|
||
|
|
static const char
|
||
|
|
rcsid[] = "$Id: m_bbox.c,v 1.1 1997/02/03 22:45:10 b1 Exp $";
|
||
|
|
|
||
|
|
#include "doomtype.h"
|
||
|
|
#include "i_system.h"
|
||
|
|
|
||
|
|
#ifdef __GNUG__
|
||
|
|
#pragma implementation "m_fixed.h"
|
||
|
|
#endif
|
||
|
|
#include "m_fixed.h"
|
||
|
|
|
||
|
|
|
||
|
|
#define abs(x) (((x)<0)?(-(x)):(x))
|
||
|
|
|
||
|
|
|
||
|
|
#if !defined(USEASM) || !defined(_M_IX86) || !defined(_MSC_VER)
|
||
|
|
|
||
|
|
// C routines
|
||
|
|
|
||
|
|
fixed_t FixedMul (fixed_t a, fixed_t b)
|
||
|
|
{
|
||
|
|
return (fixed_t)(((__int64) a * (__int64) b) >> FRACBITS);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
fixed_t FixedDiv (fixed_t a, fixed_t b)
|
||
|
|
{
|
||
|
|
if ((abs (a) >> 14) >= abs(b))
|
||
|
|
return (a^b)<0 ? MININT : MAXINT;
|
||
|
|
|
||
|
|
{
|
||
|
|
#if 0
|
||
|
|
long long c;
|
||
|
|
c = ((long long)a<<16) / ((long long)b);
|
||
|
|
return (fixed_t) c;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
double c;
|
||
|
|
|
||
|
|
c = ((double)a) / ((double)b) * FRACUNIT;
|
||
|
|
|
||
|
|
if (c >= 2147483648.0 || c < -2147483648.0)
|
||
|
|
I_Error("FixedDiv: divide by zero");
|
||
|
|
return (fixed_t) c;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#else
|
||
|
|
|
||
|
|
// Optimized (?) assembly versions
|
||
|
|
|
||
|
|
#pragma warning(disable: 4035)
|
||
|
|
|
||
|
|
fixed_t FixedMul (fixed_t a, fixed_t b)
|
||
|
|
{
|
||
|
|
__asm {
|
||
|
|
mov eax,a
|
||
|
|
imul b
|
||
|
|
shrd eax,edx,16
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
fixed_t FixedDiv (fixed_t a, fixed_t b)
|
||
|
|
{
|
||
|
|
if ((abs (a) >> 14) >= abs(b))
|
||
|
|
return (a^b)<0 ? MININT : MAXINT;
|
||
|
|
|
||
|
|
__asm {
|
||
|
|
mov eax,a // u (eax = aaaaAAAA)
|
||
|
|
mov edx,a // v (edx = aaaaAAAA)
|
||
|
|
shl eax,16 // u (eax = AAAA0000)
|
||
|
|
sar edx,16 // v (edx = ----aaaa)
|
||
|
|
idiv b // np
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#pragma warning(default: 4035)
|
||
|
|
|
||
|
|
#endif
|