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      1 //
      2 // Copyright (c) 2002-2012 The ANGLE Project Authors. All rights reserved.
      3 // Use of this source code is governed by a BSD-style license that can be
      4 // found in the LICENSE file.
      5 //
      6 
      7 // mathutil.h: Math and bit manipulation functions.
      8 
      9 #ifndef LIBGLESV2_MATHUTIL_H_
     10 #define LIBGLESV2_MATHUTIL_H_
     11 
     12 #include <intrin.h>
     13 
     14 #include "common/system.h"
     15 #include "common/debug.h"
     16 
     17 namespace gl
     18 {
     19 struct Vector4
     20 {
     21     Vector4() {}
     22     Vector4(float x, float y, float z, float w) : x(x), y(y), z(z), w(w) {}
     23 
     24     float x;
     25     float y;
     26     float z;
     27     float w;
     28 };
     29 
     30 inline bool isPow2(int x)
     31 {
     32     return (x & (x - 1)) == 0 && (x != 0);
     33 }
     34 
     35 inline int log2(int x)
     36 {
     37     int r = 0;
     38     while ((x >> r) > 1) r++;
     39     return r;
     40 }
     41 
     42 inline unsigned int ceilPow2(unsigned int x)
     43 {
     44     if (x != 0) x--;
     45     x |= x >> 1;
     46     x |= x >> 2;
     47     x |= x >> 4;
     48     x |= x >> 8;
     49     x |= x >> 16;
     50     x++;
     51 
     52     return x;
     53 }
     54 
     55 template<typename T, typename MIN, typename MAX>
     56 inline T clamp(T x, MIN min, MAX max)
     57 {
     58     // Since NaNs fail all comparison tests, a NaN value will default to min
     59     return x > min ? (x > max ? max : x) : min;
     60 }
     61 
     62 inline float clamp01(float x)
     63 {
     64     return clamp(x, 0.0f, 1.0f);
     65 }
     66 
     67 template<const int n>
     68 inline unsigned int unorm(float x)
     69 {
     70     const unsigned int max = 0xFFFFFFFF >> (32 - n);
     71 
     72     if (x > 1)
     73     {
     74         return max;
     75     }
     76     else if (x < 0)
     77     {
     78         return 0;
     79     }
     80     else
     81     {
     82         return (unsigned int)(max * x + 0.5f);
     83     }
     84 }
     85 
     86 inline bool supportsSSE2()
     87 {
     88     static bool checked = false;
     89     static bool supports = false;
     90 
     91     if (checked)
     92     {
     93         return supports;
     94     }
     95 
     96     int info[4];
     97     __cpuid(info, 0);
     98 
     99     if (info[0] >= 1)
    100     {
    101         __cpuid(info, 1);
    102 
    103         supports = (info[3] >> 26) & 1;
    104     }
    105 
    106     checked = true;
    107 
    108     return supports;
    109 }
    110 
    111 inline unsigned short float32ToFloat16(float fp32)
    112 {
    113     unsigned int fp32i = (unsigned int&)fp32;
    114     unsigned int sign = (fp32i & 0x80000000) >> 16;
    115     unsigned int abs = fp32i & 0x7FFFFFFF;
    116 
    117     if(abs > 0x47FFEFFF)   // Infinity
    118     {
    119         return sign | 0x7FFF;
    120     }
    121     else if(abs < 0x38800000)   // Denormal
    122     {
    123         unsigned int mantissa = (abs & 0x007FFFFF) | 0x00800000;
    124         int e = 113 - (abs >> 23);
    125 
    126         if(e < 24)
    127         {
    128             abs = mantissa >> e;
    129         }
    130         else
    131         {
    132             abs = 0;
    133         }
    134 
    135         return sign | (abs + 0x00000FFF + ((abs >> 13) & 1)) >> 13;
    136     }
    137     else
    138     {
    139         return sign | (abs + 0xC8000000 + 0x00000FFF + ((abs >> 13) & 1)) >> 13;
    140     }
    141 }
    142 
    143 float float16ToFloat32(unsigned short h);
    144 
    145 }
    146 
    147 namespace rx
    148 {
    149 
    150 struct Range
    151 {
    152     Range() {}
    153     Range(int lo, int hi) : start(lo), end(hi) { ASSERT(lo <= hi); }
    154 
    155     int start;
    156     int end;
    157 };
    158 
    159 }
    160 
    161 #endif   // LIBGLESV2_MATHUTIL_H_
    162