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      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 #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 (util_cpu_caps.has_sse) {
     94       mxcsr = _mm_getcsr();
     95    }
     96 #endif
     97 
     98    return mxcsr;
     99 }
    100 
    101 /**
    102  * Make sure that the fp treats the denormalized floating
    103  * point numbers as zero.
    104  *
    105  * This is the behavior required by D3D10. OpenGL doesn't care.
    106  */
    107 unsigned
    108 util_fpstate_set_denorms_to_zero(unsigned current_mxcsr)
    109 {
    110 #if defined(PIPE_ARCH_SSE)
    111    if (util_cpu_caps.has_sse) {
    112       /* Enable flush to zero mode */
    113       current_mxcsr |= _MM_FLUSH_ZERO_MASK;
    114       if (util_cpu_caps.has_daz) {
    115          /* Enable denormals are zero mode */
    116          current_mxcsr |= _MM_DENORMALS_ZERO_MASK;
    117       }
    118       util_fpstate_set(current_mxcsr);
    119    }
    120 #endif
    121    return current_mxcsr;
    122 }
    123 
    124 /**
    125  * Set the state of the fpstate (mxcsr on x86) register.
    126  *
    127  * On platforms without support for it's a noop.
    128  */
    129 void
    130 util_fpstate_set(unsigned mxcsr)
    131 {
    132 #if defined(PIPE_ARCH_SSE)
    133    if (util_cpu_caps.has_sse) {
    134       _mm_setcsr(mxcsr);
    135    }
    136 #endif
    137 }
    138