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It's now possible to build SDL without any C runtime at all on Windows, using Visual C++ 2005
author Sam Lantinga <slouken@libsdl.org>
date Mon, 06 Feb 2006 08:28:51 +0000
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children 62802d9d7c87
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1329:bc67bbf87818 1330:450721ad5436
1 /*
2 * ====================================================
3 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
4 *
5 * Developed at SunPro, a Sun Microsystems, Inc. business.
6 * Permission to use, copy, modify, and distribute this
7 * software is freely granted, provided that this notice
8 * is preserved.
9 * ====================================================
10 */
11
12 /*
13 * from: @(#)fdlibm.h 5.1 93/09/24
14 * $Id$
15 */
16
17 #ifndef _MATH_PRIVATE_H_
18 #define _MATH_PRIVATE_H_
19
20 #include "SDL_endian.h"
21
22 typedef Sint32 int32_t;
23 typedef Uint32 u_int32_t;
24
25 /* The original fdlibm code used statements like:
26 n0 = ((*(int*)&one)>>29)^1; * index of high word *
27 ix0 = *(n0+(int*)&x); * high word of x *
28 ix1 = *((1-n0)+(int*)&x); * low word of x *
29 to dig two 32 bit words out of the 64 bit IEEE floating point
30 value. That is non-ANSI, and, moreover, the gcc instruction
31 scheduler gets it wrong. We instead use the following macros.
32 Unlike the original code, we determine the endianness at compile
33 time, not at run time; I don't see much benefit to selecting
34 endianness at run time. */
35
36 /* A union which permits us to convert between a double and two 32 bit
37 ints. */
38
39 /*
40 * Math on arm is special:
41 * For FPA, float words are always big-endian.
42 * For VFP, floats words follow the memory system mode.
43 */
44
45 #if (SDL_BYTEORDER == SDL_BIG_ENDIAN) || \
46 (!defined(__VFP_FP__) && (defined(__arm__) || defined(__thumb__)))
47
48 typedef union
49 {
50 double value;
51 struct
52 {
53 u_int32_t msw;
54 u_int32_t lsw;
55 } parts;
56 } ieee_double_shape_type;
57
58 #else
59
60 typedef union
61 {
62 double value;
63 struct
64 {
65 u_int32_t lsw;
66 u_int32_t msw;
67 } parts;
68 } ieee_double_shape_type;
69
70 #endif
71
72 /* Get two 32 bit ints from a double. */
73
74 #define EXTRACT_WORDS(ix0,ix1,d) \
75 do { \
76 ieee_double_shape_type ew_u; \
77 ew_u.value = (d); \
78 (ix0) = ew_u.parts.msw; \
79 (ix1) = ew_u.parts.lsw; \
80 } while (0)
81
82 /* Get the more significant 32 bit int from a double. */
83
84 #define GET_HIGH_WORD(i,d) \
85 do { \
86 ieee_double_shape_type gh_u; \
87 gh_u.value = (d); \
88 (i) = gh_u.parts.msw; \
89 } while (0)
90
91 /* Get the less significant 32 bit int from a double. */
92
93 #define GET_LOW_WORD(i,d) \
94 do { \
95 ieee_double_shape_type gl_u; \
96 gl_u.value = (d); \
97 (i) = gl_u.parts.lsw; \
98 } while (0)
99
100 /* Set a double from two 32 bit ints. */
101
102 #define INSERT_WORDS(d,ix0,ix1) \
103 do { \
104 ieee_double_shape_type iw_u; \
105 iw_u.parts.msw = (ix0); \
106 iw_u.parts.lsw = (ix1); \
107 (d) = iw_u.value; \
108 } while (0)
109
110 /* Set the more significant 32 bits of a double from an int. */
111
112 #define SET_HIGH_WORD(d,v) \
113 do { \
114 ieee_double_shape_type sh_u; \
115 sh_u.value = (d); \
116 sh_u.parts.msw = (v); \
117 (d) = sh_u.value; \
118 } while (0)
119
120 /* Set the less significant 32 bits of a double from an int. */
121
122 #define SET_LOW_WORD(d,v) \
123 do { \
124 ieee_double_shape_type sl_u; \
125 sl_u.value = (d); \
126 sl_u.parts.lsw = (v); \
127 (d) = sl_u.value; \
128 } while (0)
129
130 /* A union which permits us to convert between a float and a 32 bit
131 int. */
132
133 typedef union
134 {
135 float value;
136 u_int32_t word;
137 } ieee_float_shape_type;
138
139 /* Get a 32 bit int from a float. */
140
141 #define GET_FLOAT_WORD(i,d) \
142 do { \
143 ieee_float_shape_type gf_u; \
144 gf_u.value = (d); \
145 (i) = gf_u.word; \
146 } while (0)
147
148 /* Set a float from a 32 bit int. */
149
150 #define SET_FLOAT_WORD(d,i) \
151 do { \
152 ieee_float_shape_type sf_u; \
153 sf_u.word = (i); \
154 (d) = sf_u.value; \
155 } while (0)
156
157
158 #ifdef __STDC__
159 static const double
160 #else
161 static double
162 #endif
163 zero = 0.0,
164 one = 1.0,
165 two = 2.0,
166 two53 = 9007199254740992.0, /* 0x43400000, 0x00000000 */
167 two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
168 twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
169 huge = 1.0e+300,
170 tiny = 1.0e-300;
171
172 #endif /* _MATH_PRIVATE_H_ */