1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id: m_fixed.c 8 2005-07-23 16:44:57Z fraggle $
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005 Simon Howard
//
// 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.
//
// $Log$
// Revision 1.2 2005/07/23 16:44:55 fraggle
// Update copyright to GNU GPL
//
// Revision 1.1.1.1 2005/07/23 16:19:54 fraggle
// Initial import
//
//
// DESCRIPTION:
// Fixed point implementation.
//
//-----------------------------------------------------------------------------
static const char
rcsid[] = "$Id: m_fixed.c 8 2005-07-23 16:44:57Z fraggle $";
#include "stdlib.h"
#include "doomtype.h"
#include "i_system.h"
#ifdef __GNUG__
#pragma implementation "m_fixed.h"
#endif
#include "m_fixed.h"
// Fixme. __USE_C_FIXED__ or something.
fixed_t
FixedMul
( fixed_t a,
fixed_t b )
{
return ((long long) a * (long long) b) >> FRACBITS;
}
//
// FixedDiv, C version.
//
fixed_t
FixedDiv
( fixed_t a,
fixed_t b )
{
if ( (abs(a)>>14) >= abs(b))
return (a^b)<0 ? MININT : MAXINT;
return FixedDiv2 (a,b);
}
fixed_t
FixedDiv2
( fixed_t a,
fixed_t b )
{
#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;
}
|
