Go to most recent revision | Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 3584 | sourcerer | 1 | /* |
| 2 | * This file is part of LibCSS. |
||
| 3 | * Licensed under the MIT License, |
||
| 4 | * http://www.opensource.org/licenses/mit-license.php |
||
| 5 | * Copyright 2008 John-Mark Bell |
||
| 6 | */ |
||
| 7 | |||
| 8 | #ifndef libcss_fpmath_h_ |
||
| 9 | #define libcss_fpmath_h_ |
||
| 10 | |||
| 11 | #ifdef __cplusplus |
||
| 12 | extern "C" |
||
| 13 | { |
||
| 14 | #endif |
||
| 15 | |||
| 16 | #include |
||
| 17 | #include |
||
| 18 | |||
| 19 | /* 22:10 fixed point math */ |
||
| 20 | #define CSS_RADIX_POINT 10 |
||
| 21 | |||
| 22 | /* type for fixed point numbers */ |
||
| 23 | typedef int32_t css_fixed; |
||
| 24 | |||
| 25 | static inline css_fixed |
||
| 26 | css_add_fixed(const css_fixed x, const css_fixed y) { |
||
| 27 | int32_t ux = x; |
||
| 28 | int32_t uy = y; |
||
| 29 | int32_t res = ux + uy; |
||
| 30 | |||
| 31 | /* Calculate overflowed result. (Don't change the sign bit of ux) */ |
||
| 32 | ux = (ux >> 31) + INT_MAX; |
||
| 33 | |||
| 34 | /* Force compiler to use cmovns instruction */ |
||
| 35 | if ((int32_t) ((ux ^ uy) | ~(uy ^ res)) >= 0) { |
||
| 36 | res = ux; |
||
| 37 | } |
||
| 38 | |||
| 39 | return res; |
||
| 40 | } |
||
| 41 | |||
| 42 | static inline css_fixed |
||
| 43 | css_subtract_fixed(const css_fixed x, const css_fixed y) { |
||
| 44 | int32_t ux = x; |
||
| 45 | int32_t uy = y; |
||
| 46 | int32_t res = ux - uy; |
||
| 47 | |||
| 48 | ux = (ux >> 31) + INT_MAX; |
||
| 49 | |||
| 50 | /* Force compiler to use cmovns instruction */ |
||
| 51 | if ((int32_t)((ux ^ uy) & (ux ^ res)) < 0) { |
||
| 52 | res = ux; |
||
| 53 | } |
||
| 54 | |||
| 55 | return res; |
||
| 56 | } |
||
| 57 | |||
| 58 | static inline css_fixed |
||
| 59 | css_divide_fixed(const css_fixed x, const css_fixed y) { |
||
| 60 | int64_t xx = ((int64_t)x << CSS_RADIX_POINT) / y; |
||
| 61 | |||
| 62 | if (xx < INT_MIN) |
||
| 63 | xx = INT_MIN; |
||
| 64 | |||
| 65 | if (xx > INT_MAX) |
||
| 66 | xx = INT_MAX; |
||
| 67 | |||
| 68 | return xx; |
||
| 69 | } |
||
| 70 | |||
| 71 | static inline css_fixed |
||
| 72 | css_multiply_fixed(const css_fixed x, const css_fixed y) { |
||
| 73 | int64_t xx = ((int64_t)x * (int64_t)y) >> CSS_RADIX_POINT; |
||
| 74 | |||
| 75 | if (xx < INT_MIN) |
||
| 76 | xx = INT_MIN; |
||
| 77 | |||
| 78 | if (xx > INT_MAX) |
||
| 79 | xx = INT_MAX; |
||
| 80 | |||
| 81 | return xx; |
||
| 82 | } |
||
| 83 | |||
| 84 | static inline css_fixed |
||
| 85 | css_int_to_fixed(const int a) { |
||
| 86 | int64_t xx = ((int64_t) a) << CSS_RADIX_POINT; |
||
| 87 | |||
| 88 | if (xx < INT_MIN) |
||
| 89 | xx = INT_MIN; |
||
| 90 | |||
| 91 | if (xx > INT_MAX) |
||
| 92 | xx = INT_MAX; |
||
| 93 | |||
| 94 | return xx; |
||
| 95 | } |
||
| 96 | |||
| 97 | static inline css_fixed |
||
| 98 | css_float_to_fixed(const float a) { |
||
| 99 | float xx = a * (float) (1 << CSS_RADIX_POINT); |
||
| 100 | |||
| 101 | if (xx < INT_MIN) |
||
| 102 | xx = INT_MIN; |
||
| 103 | |||
| 104 | if (xx > INT_MAX) |
||
| 105 | xx = INT_MAX; |
||
| 106 | |||
| 107 | return (css_fixed) xx; |
||
| 108 | } |
||
| 109 | |||
| 110 | /* Add two fixed point values */ |
||
| 111 | #define FADD(a, b) (css_add_fixed((a), (b))) |
||
| 112 | /* Subtract two fixed point values */ |
||
| 113 | #define FSUB(a, b) (css_subtract_fixed((a), (b))) |
||
| 114 | /* Multiply two fixed point values */ |
||
| 115 | #define FMUL(a, b) (css_multiply_fixed((a), (b))) |
||
| 116 | /* Divide two fixed point values */ |
||
| 117 | #define FDIV(a, b) (css_divide_fixed((a), (b))) |
||
| 118 | |||
| 119 | /* Convert a floating point value to fixed point */ |
||
| 120 | #define FLTTOFIX(a) ((css_fixed) ((a) * (float) (1 << CSS_RADIX_POINT))) |
||
| 121 | /* Convert a fixed point value to floating point */ |
||
| 122 | #define FIXTOFLT(a) ((float) (a) / (float) (1 << CSS_RADIX_POINT)) |
||
| 123 | |||
| 124 | /* Convert an integer to a fixed point value */ |
||
| 125 | #define INTTOFIX(a) (css_int_to_fixed(a)) |
||
| 126 | /* Convert a fixed point value to an integer */ |
||
| 127 | #define FIXTOINT(a) ((a) >> CSS_RADIX_POINT) |
||
| 128 | |||
| 129 | /* truncate a fixed point value */ |
||
| 130 | #define TRUNCATEFIX(a) (a & ~((1 << CSS_RADIX_POINT)- 1 )) |
||
| 131 | |||
| 132 | /* Useful values */ |
||
| 133 | #define F_PI_2 0x00000648 /* 1.5708 (PI/2) */ |
||
| 134 | #define F_PI 0x00000c91 /* 3.1415 (PI) */ |
||
| 135 | #define F_3PI_2 0x000012d9 /* 4.7124 (3PI/2) */ |
||
| 136 | #define F_2PI 0x00001922 /* 6.2831 (2 PI) */ |
||
| 137 | |||
| 138 | #define F_90 0x00016800 /* 90 */ |
||
| 139 | #define F_180 0x0002d000 /* 180 */ |
||
| 140 | #define F_270 0x00043800 /* 270 */ |
||
| 141 | #define F_360 0x0005a000 /* 360 */ |
||
| 142 | |||
| 143 | #define F_0_5 0x00000200 /* 0.5 */ |
||
| 144 | #define F_1 0x00000400 /* 1 */ |
||
| 145 | #define F_10 0x00002800 /* 10 */ |
||
| 146 | #define F_72 0x00012000 /* 72 */ |
||
| 147 | #define F_100 0x00019000 /* 100 */ |
||
| 148 | #define F_200 0x00032000 /* 200 */ |
||
| 149 | #define F_255 0x0003FC00 /* 255 */ |
||
| 150 | #define F_300 0x0004b000 /* 300 */ |
||
| 151 | #define F_400 0x00064000 /* 400 */ |
||
| 152 | |||
| 153 | #ifdef __cplusplus |
||
| 154 | } |
||
| 155 | #endif |
||
| 156 | |||
| 157 | #endif |
||
| 158 |