1 /* 2 * Copyright 2006 The Android Open Source Project 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkFixed_DEFINED 9 #define SkFixed_DEFINED 10 11 #include "SkTypes.h" 12 13 /** \file SkFixed.h 14 15 Types and macros for 16.16 fixed point 16 */ 17 18 /** 32 bit signed integer used to represent fractions values with 16 bits to the right of the decimal point 19 */ 20 typedef int32_t SkFixed; 21 #define SK_Fixed1 (1 << 16) 22 #define SK_FixedHalf (1 << 15) 23 #define SK_FixedMax (0x7FFFFFFF) 24 #define SK_FixedMin (-SK_FixedMax) 25 #define SK_FixedNaN ((int) 0x80000000) 26 #define SK_FixedPI (0x3243F) 27 #define SK_FixedSqrt2 (92682) 28 #define SK_FixedTanPIOver8 (0x6A0A) 29 #define SK_FixedRoot2Over2 (0xB505) 30 31 #define SkFixedToFloat(x) ((x) * 1.52587890625e-5f) 32 #if 1 33 #define SkFloatToFixed(x) ((SkFixed)((x) * SK_Fixed1)) 34 #else 35 // pins over/under flows to max/min int32 (slower than just a cast) 36 static inline SkFixed SkFloatToFixed(float x) { 37 int64_t n = x * SK_Fixed1; 38 return (SkFixed)n; 39 } 40 #endif 41 42 #ifdef SK_DEBUG 43 static inline SkFixed SkFloatToFixed_Check(float x) { 44 int64_t n64 = (int64_t)(x * SK_Fixed1); 45 SkFixed n32 = (SkFixed)n64; 46 SkASSERT(n64 == n32); 47 return n32; 48 } 49 #else 50 #define SkFloatToFixed_Check(x) SkFloatToFixed(x) 51 #endif 52 53 #define SkFixedToDouble(x) ((x) * 1.52587890625e-5) 54 #define SkDoubleToFixed(x) ((SkFixed)((x) * SK_Fixed1)) 55 56 /** Converts an integer to a SkFixed, asserting that the result does not overflow 57 a 32 bit signed integer 58 */ 59 #ifdef SK_DEBUG 60 inline SkFixed SkIntToFixed(int n) 61 { 62 SkASSERT(n >= -32768 && n <= 32767); 63 return n << 16; 64 } 65 #else 66 // force the cast to SkFixed to ensure that the answer is signed (like the debug version) 67 #define SkIntToFixed(n) (SkFixed)((n) << 16) 68 #endif 69 70 #define SkFixedRoundToInt(x) (((x) + SK_FixedHalf) >> 16) 71 #define SkFixedCeilToInt(x) (((x) + SK_Fixed1 - 1) >> 16) 72 #define SkFixedFloorToInt(x) ((x) >> 16) 73 74 #define SkFixedRoundToFixed(x) (((x) + SK_FixedHalf) & 0xFFFF0000) 75 #define SkFixedCeilToFixed(x) (((x) + SK_Fixed1 - 1) & 0xFFFF0000) 76 #define SkFixedFloorToFixed(x) ((x) & 0xFFFF0000) 77 78 #define SkFixedAbs(x) SkAbs32(x) 79 #define SkFixedAve(a, b) (((a) + (b)) >> 1) 80 81 #define SkFixedDiv(numer, denom) SkDivBits(numer, denom, 16) 82 83 ////////////////////////////////////////////////////////////////////////////////////////////////////// 84 // Now look for ASM overrides for our portable versions (should consider putting this in its own file) 85 86 inline SkFixed SkFixedMul_longlong(SkFixed a, SkFixed b) { 87 return (SkFixed)((int64_t)a * b >> 16); 88 } 89 #define SkFixedMul(a,b) SkFixedMul_longlong(a,b) 90 91 92 #if defined(SK_CPU_ARM32) 93 /* This guy does not handle NaN or other obscurities, but is faster than 94 than (int)(x*65536). When built on Android with -Os, needs forcing 95 to inline or we lose the speed benefit. 96 */ 97 SK_ALWAYS_INLINE SkFixed SkFloatToFixed_arm(float x) 98 { 99 int32_t y, z; 100 asm("movs %1, %3, lsl #1 \n" 101 "mov %2, #0x8E \n" 102 "sub %1, %2, %1, lsr #24 \n" 103 "mov %2, %3, lsl #8 \n" 104 "orr %2, %2, #0x80000000 \n" 105 "mov %1, %2, lsr %1 \n" 106 "it cs \n" 107 "rsbcs %1, %1, #0 \n" 108 : "=r"(x), "=&r"(y), "=&r"(z) 109 : "r"(x) 110 : "cc" 111 ); 112 return y; 113 } 114 inline SkFixed SkFixedMul_arm(SkFixed x, SkFixed y) 115 { 116 int32_t t; 117 asm("smull %0, %2, %1, %3 \n" 118 "mov %0, %0, lsr #16 \n" 119 "orr %0, %0, %2, lsl #16 \n" 120 : "=r"(x), "=&r"(y), "=r"(t) 121 : "r"(x), "1"(y) 122 : 123 ); 124 return x; 125 } 126 #undef SkFixedMul 127 #define SkFixedMul(x, y) SkFixedMul_arm(x, y) 128 129 #undef SkFloatToFixed 130 #define SkFloatToFixed(x) SkFloatToFixed_arm(x) 131 #endif 132 133 /////////////////////////////////////////////////////////////////////////////// 134 135 typedef int64_t SkFixed3232; // 32.32 136 137 #define SkIntToFixed3232(x) ((SkFixed3232)(x) << 32) 138 #define SkFixed3232ToInt(x) ((int)((x) >> 32)) 139 #define SkFixedToFixed3232(x) ((SkFixed3232)(x) << 16) 140 #define SkFixed3232ToFixed(x) ((SkFixed)((x) >> 16)) 141 #define SkFloatToFixed3232(x) ((SkFixed3232)((x) * (65536.0f * 65536.0f))) 142 143 #define SkScalarToFixed3232(x) SkFloatToFixed3232(x) 144 145 /////////////////////////////////////////////////////////////////////////////// 146 147 // 64bits wide, with a 16bit bias. Useful when accumulating lots of 16.16 so 148 // we don't overflow along the way 149 typedef int64_t Sk48Dot16; 150 151 #define Sk48Dot16FloorToInt(x) static_cast<int>((x) >> 16) 152 153 static inline float Sk48Dot16ToScalar(Sk48Dot16 x) { 154 return static_cast<float>(x * 1.5258789e-5); // x * (1.0f / (1 << 16)) 155 } 156 #define SkFloatTo48Dot16(x) (static_cast<Sk48Dot16>((x) * (1 << 16))) 157 158 #define SkScalarTo48Dot16(x) SkFloatTo48Dot16(x) 159 160 #endif 161
