source: trunk/src/half.h @ 879

Last change on this file since 879 was 879, checked in by sam, 8 years ago

core: tune the half precision code so that the best variants are being
used on the PS3 platform.

  • Property svn:keywords set to Id
File size: 3.5 KB
Line 
1//
2// Lol Engine
3//
4// Copyright: (c) 2010-2011 Sam Hocevar <sam@hocevar.net>
5//   This program is free software; you can redistribute it and/or
6//   modify it under the terms of the Do What The Fuck You Want To
7//   Public License, Version 2, as published by Sam Hocevar. See
8//   http://sam.zoy.org/projects/COPYING.WTFPL for more details.
9//
10
11//
12// The Half class
13// --------------
14//
15
16#if !defined __LOL_HALF_H__
17#define __LOL_HALF_H__
18
19#include <cstdio>
20#include <stdint.h>
21
22namespace lol
23{
24
25class half
26{
27public:
28    /* Constructors. Always inline so that the code can work in registers
29     * instead of calling routines with the hidden "this" parameter. */
30    inline half() { }
31    inline half(float f) { *this = makefast(f); }
32
33    inline int is_nan() const
34    {
35        return ((bits & 0x7c00u) == 0x7c00u) && (bits & 0x03ffu);
36    }
37
38    inline int is_finite() const
39    {
40        return (bits & 0x7c00u) != 0x7c00u;
41    }
42
43    inline int is_inf() const
44    {
45        return (uint16_t)(bits << 1) == (0x7c00u << 1);
46    }
47
48    inline int is_normal() const
49    {
50        return (is_finite() && (bits & 0x7c00u)) || ((bits & 0x7fffu) == 0);
51    }
52
53    /* Cast to other types */
54    operator float() const;
55    inline operator int() const { return (int)(float)*this; }
56
57    /* Array conversions */
58    static size_t convert(half *dst, float const *src, size_t nelem);
59    static size_t convert(float *dst, half const *src, size_t nelem);
60
61    /* Operations */
62    inline half operator -() { return makebits(bits ^ 0x8000u); }
63    inline half &operator +=(float f) { return (*this = (half)(*this + f)); }
64    inline half &operator -=(float f) { return (*this = (half)(*this - f)); }
65    inline half &operator *=(float f) { return (*this = (half)(*this * f)); }
66    inline half &operator /=(float f) { return (*this = (half)(*this / f)); }
67    inline half &operator +=(half h) { return (*this = (half)(*this + h)); }
68    inline half &operator -=(half h) { return (*this = (half)(*this - h)); }
69    inline half &operator *=(half h) { return (*this = (half)(*this * h)); }
70    inline half &operator /=(half h) { return (*this = (half)(*this / h)); }
71
72    inline float operator +(float f) const { return (float)*this + f; }
73    inline float operator -(float f) const { return (float)*this - f; }
74    inline float operator *(float f) const { return (float)*this * f; }
75    inline float operator /(float f) const { return (float)*this / f; }
76    inline float operator +(half h) const { return (float)*this + (float)h; }
77    inline float operator -(half h) const { return (float)*this - (float)h; }
78    inline float operator *(half h) const { return (float)*this * (float)h; }
79    inline float operator /(half h) const { return (float)*this / (float)h; }
80
81    /* Factories */
82    static half makefast(float f);
83    static half makeaccurate(float f);
84    static inline half makebits(uint16_t x)
85    {
86        half ret;
87        ret.bits = x;
88        return ret;
89    }
90
91    /* Internal representation */
92    uint16_t bits;
93};
94
95inline float &operator +=(float &f, half h) { return f += (float)h; }
96inline float &operator -=(float &f, half h) { return f -= (float)h; }
97inline float &operator *=(float &f, half h) { return f *= (float)h; }
98inline float &operator /=(float &f, half h) { return f /= (float)h; }
99
100inline float operator +(float f, half h) { return f + (float)h; }
101inline float operator -(float f, half h) { return f - (float)h; }
102inline float operator *(float f, half h) { return f * (float)h; }
103inline float operator /(float f, half h) { return f / (float)h; }
104
105} /* namespace lol */
106
107#endif // __LOL_HALF_H__
108
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