utils/u_math: break dependency on gallium/utils
[mesa.git] / src / util / u_math.c
1 /**************************************************************************
2 *
3 * Copyright 2008 VMware, Inc.
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14 * The above copyright notice and this permission notice (including the
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16 * of the Software.
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26 **************************************************************************/
27
28
29
30 #include "pipe/p_config.h"
31 #include "util/u_math.h"
32 #include "x86/common_x86_features.h"
33
34 #if defined(PIPE_ARCH_SSE)
35 #include <xmmintrin.h>
36 /* This is defined in pmmintrin.h, but it can only be included when -msse3 is
37 * used, so just define it here to avoid further. */
38 #define _MM_DENORMALS_ZERO_MASK 0x0040
39 #endif
40
41
42 /** 2^x, for x in [-1.0, 1.0) */
43 float pow2_table[POW2_TABLE_SIZE];
44
45
46 static void
47 init_pow2_table(void)
48 {
49 int i;
50 for (i = 0; i < POW2_TABLE_SIZE; i++)
51 pow2_table[i] = exp2f((i - POW2_TABLE_OFFSET) / POW2_TABLE_SCALE);
52 }
53
54
55 /** log2(x), for x in [1.0, 2.0) */
56 float log2_table[LOG2_TABLE_SIZE];
57
58
59 static void
60 init_log2_table(void)
61 {
62 unsigned i;
63 for (i = 0; i < LOG2_TABLE_SIZE; i++)
64 log2_table[i] = (float) log2(1.0 + i * (1.0 / LOG2_TABLE_SCALE));
65 }
66
67
68 /**
69 * One time init for math utilities.
70 */
71 void
72 util_init_math(void)
73 {
74 static boolean initialized = FALSE;
75 if (!initialized) {
76 init_pow2_table();
77 init_log2_table();
78 initialized = TRUE;
79 }
80 }
81
82 /**
83 * Fetches the contents of the fpstate (mxcsr on x86) register.
84 *
85 * On platforms without support for it just returns 0.
86 */
87 unsigned
88 util_fpstate_get(void)
89 {
90 unsigned mxcsr = 0;
91
92 #if defined(PIPE_ARCH_SSE)
93 if (cpu_has_xmm) {
94 mxcsr = _mm_getcsr();
95 }
96 #endif
97
98 return mxcsr;
99 }
100
101 /* TODO: this was copied from u_cpu_detection. It's another case of duplication
102 * between gallium and core mesa, and it would be nice to get rid of that
103 * duplication as well.
104 */
105 #if defined(PIPE_ARCH_X86)
106 PIPE_ALIGN_STACK static inline bool sse2_has_daz(void)
107 {
108 struct {
109 uint32_t pad1[7];
110 uint32_t mxcsr_mask;
111 uint32_t pad2[128-8];
112 } PIPE_ALIGN_VAR(16) fxarea;
113
114 fxarea.mxcsr_mask = 0;
115 #if defined(PIPE_CC_GCC)
116 __asm __volatile ("fxsave %0" : "+m" (fxarea));
117 #elif defined(PIPE_CC_MSVC) || defined(PIPE_CC_ICL)
118 _fxsave(&fxarea);
119 #else
120 fxarea.mxcsr_mask = 0;
121 #endif
122 return !!(fxarea.mxcsr_mask & (1 << 6));
123 }
124 #endif
125
126 /**
127 * Make sure that the fp treats the denormalized floating
128 * point numbers as zero.
129 *
130 * This is the behavior required by D3D10. OpenGL doesn't care.
131 */
132 unsigned
133 util_fpstate_set_denorms_to_zero(unsigned current_mxcsr)
134 {
135 #if defined(PIPE_ARCH_SSE)
136 if (cpu_has_xmm) {
137 /* Enable flush to zero mode */
138 current_mxcsr |= _MM_FLUSH_ZERO_MASK;
139 /* x86_64 cpus always have daz, as do cpus with sse3 in fact, there's
140 * basically only a handful of very early pentium 4's that have sse2 but
141 * not daz.
142 */
143 # if !defined(PIPE_ARCH_x86_64) && !defined(PIPE_ARCH_SSSE3)
144 if (sse2_has_daz()) {
145 # endif
146 /* Enable denormals are zero mode */
147 current_mxcsr |= _MM_DENORMALS_ZERO_MASK;
148 # if !defined(PIPE_ARCH_x86_64) && !defined(PIPE_ARCH_SSSE3)
149 }
150 #endif
151 util_fpstate_set(current_mxcsr);
152 }
153 #endif
154 return current_mxcsr;
155 }
156
157 /**
158 * Set the state of the fpstate (mxcsr on x86) register.
159 *
160 * On platforms without support for it's a noop.
161 */
162 void
163 util_fpstate_set(unsigned mxcsr)
164 {
165 #if defined(PIPE_ARCH_SSE)
166 if (cpu_has_xmm) {
167 _mm_setcsr(mxcsr);
168 }
169 #endif
170 }