src/util/u_math.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2008 VMware, Inc.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28
  29
  30 #include "pipe/p_config.h"
  31 #include "util/u_math.h"
  32 #include "util/u_cpu_detect.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 #ifndef _MM_DENORMALS_ZERO_MASK
  39 #define _MM_DENORMALS_ZERO_MASK 0x0040
  40 #endif
  41 #endif
  42
  43
  44 /** 2^x, for x in [-1.0, 1.0) */
  45 float pow2_table[POW2_TABLE_SIZE];
  46
  47
  48 static void
  49 init_pow2_table(void)
  50 {
  51    int i;
  52    for (i = 0; i < POW2_TABLE_SIZE; i++)
  53       pow2_table[i] = exp2f((i - POW2_TABLE_OFFSET) / POW2_TABLE_SCALE);
  54 }
  55
  56
  57 /** log2(x), for x in [1.0, 2.0) */
  58 float log2_table[LOG2_TABLE_SIZE];
  59
  60
  61 static void
  62 init_log2_table(void)
  63 {
  64    unsigned i;
  65    for (i = 0; i < LOG2_TABLE_SIZE; i++)
  66       log2_table[i] = (float) log2(1.0 + i * (1.0 / LOG2_TABLE_SCALE));
  67 }
  68
  69
  70 /**
  71  * One time init for math utilities.
  72  */
  73 void
  74 util_init_math(void)
  75 {
  76    static bool initialized = false;
  77    if (!initialized) {
  78       init_pow2_table();
  79       init_log2_table();
  80       initialized = true;
  81    }
  82 }
  83
  84 /**
  85  * Fetches the contents of the fpstate (mxcsr on x86) register.
  86  *
  87  * On platforms without support for it just returns 0.
  88  */
  89 unsigned
  90 util_fpstate_get(void)
  91 {
  92    unsigned mxcsr = 0;
  93
  94 #if defined(PIPE_ARCH_SSE)
  95    if (util_cpu_caps.has_sse) {
  96       mxcsr = _mm_getcsr();
  97    }
  98 #endif
  99
 100    return mxcsr;
 101 }
 102
 103 /**
 104  * Make sure that the fp treats the denormalized floating
 105  * point numbers as zero.
 106  *
 107  * This is the behavior required by D3D10. OpenGL doesn't care.
 108  */
 109 unsigned
 110 util_fpstate_set_denorms_to_zero(unsigned current_mxcsr)
 111 {
 112 #if defined(PIPE_ARCH_SSE)
 113    if (util_cpu_caps.has_sse) {
 114       /* Enable flush to zero mode */
 115       current_mxcsr |= _MM_FLUSH_ZERO_MASK;
 116       if (util_cpu_caps.has_daz) {
 117          /* Enable denormals are zero mode */
 118          current_mxcsr |= _MM_DENORMALS_ZERO_MASK;
 119       }
 120       util_fpstate_set(current_mxcsr);
 121    }
 122 #endif
 123    return current_mxcsr;
 124 }
 125
 126 /**
 127  * Set the state of the fpstate (mxcsr on x86) register.
 128  *
 129  * On platforms without support for it's a noop.
 130  */
 131 void
 132 util_fpstate_set(unsigned mxcsr)
 133 {
 134 #if defined(PIPE_ARCH_SSE)
 135    if (util_cpu_caps.has_sse) {
 136       _mm_setcsr(mxcsr);
 137    }
 138 #endif
 139 }