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1 | 1 |
2 /* | 2 /* |
3 * Copyright 2006 The Android Open Source Project | 3 * Copyright 2006 The Android Open Source Project |
4 * | 4 * |
5 * Use of this source code is governed by a BSD-style license that can be | 5 * Use of this source code is governed by a BSD-style license that can be |
6 * found in the LICENSE file. | 6 * found in the LICENSE file. |
7 */ | 7 */ |
8 | 8 |
9 | 9 |
10 #ifndef SkFloatingPoint_DEFINED | 10 #ifndef SkFloatingPoint_DEFINED |
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89 #define sk_float_ceil2int(x) (int)sk_float_ceil(x) | 89 #define sk_float_ceil2int(x) (int)sk_float_ceil(x) |
90 #endif | 90 #endif |
91 | 91 |
92 extern const uint32_t gIEEENotANumber; | 92 extern const uint32_t gIEEENotANumber; |
93 extern const uint32_t gIEEEInfinity; | 93 extern const uint32_t gIEEEInfinity; |
94 extern const uint32_t gIEEENegativeInfinity; | 94 extern const uint32_t gIEEENegativeInfinity; |
95 | 95 |
96 #define SK_FloatNaN (*SkTCast<const float*>(&gIEEENotANumber)) | 96 #define SK_FloatNaN (*SkTCast<const float*>(&gIEEENotANumber)) |
97 #define SK_FloatInfinity (*SkTCast<const float*>(&gIEEEInfinity)) | 97 #define SK_FloatInfinity (*SkTCast<const float*>(&gIEEEInfinity)) |
98 #define SK_FloatNegativeInfinity (*SkTCast<const float*>(&gIEEENegativeInfini ty)) | 98 #define SK_FloatNegativeInfinity (*SkTCast<const float*>(&gIEEENegativeInfini ty)) |
99 | |
100 #ifdef __SSE__ | |
101 #include <xmmintrin.h> | |
99 #endif | 102 #endif |
103 | |
104 // Fast, approximate inverse square root. | |
105 // Compare to name-brand "1.0f / sk_float_sqrt(x)". | |
106 inline float sk_float_rsqrt(float x) { | |
reed1
2013/11/07 22:28:44
static ...
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107 // We want all this inlined, so we'll inline SIMD and just take the hit when we don't know we've got | |
108 // it at compile time. This is going to be too fast to productively hide behind a function pointer. | |
109 #ifdef __SSE__ | |
110 float result; | |
111 _mm_store_ss(&result, _mm_rsqrt_ss(_mm_set_ss(x))); | |
112 return result; | |
113 #else | |
114 // TODO(mtklein): NEON | |
115 float xhalf = 0.5f*x; | |
116 int i = *SkTCast<int*>(&x); | |
117 i = 0x5f3759df - (i>>1); | |
118 x = *SkTCast<float*>(&i); | |
119 x = x*(1.5f-xhalf*x*x); | |
120 // x = x*(1.5f-xhalf*x*x); // this line takes err from 10^-3 to 10^-6, but at what cost!?!? | |
121 return x; | |
122 #endif | |
123 } | |
124 | |
125 #endif | |
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