95dd17737d
This reverts commit fb28cd2b13.
BUG=skia:
TBR=
Review URL: https://codereview.chromium.org/1298833002
171 lines
6.0 KiB
C++
171 lines
6.0 KiB
C++
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/*
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* Copyright 2006 The Android Open Source Project
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkFloatingPoint_DEFINED
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#define SkFloatingPoint_DEFINED
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#include "SkTypes.h"
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#include <math.h>
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#include <float.h>
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// For _POSIX_VERSION
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#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
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#include <unistd.h>
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#endif
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#include "SkFloatBits.h"
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// C++98 cmath std::pow seems to be the earliest portable way to get float pow.
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// However, on Linux including cmath undefines isfinite.
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// http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14608
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static inline float sk_float_pow(float base, float exp) {
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return powf(base, exp);
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}
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static inline float sk_float_copysign(float x, float y) {
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// c++11 contains a 'float copysign(float, float)' function in <cmath>.
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// clang-cl reports __cplusplus for clang, not the __cplusplus vc++ version _MSC_VER would report.
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#if (defined(_MSC_VER) && defined(__clang__))
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# define SK_BUILD_WITH_CLANG_CL 1
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#else
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# define SK_BUILD_WITH_CLANG_CL 0
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#endif
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#if (!SK_BUILD_WITH_CLANG_CL && __cplusplus >= 201103L) || (_MSC_VER >= 1800)
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return copysignf(x, y);
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// Posix has demanded 'float copysignf(float, float)' (from C99) since Issue 6.
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#elif defined(_POSIX_VERSION) && _POSIX_VERSION >= 200112L
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return copysignf(x, y);
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// Visual studio prior to 13 only has 'double _copysign(double, double)'.
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#elif defined(_MSC_VER)
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return (float)_copysign(x, y);
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// Otherwise convert to bits and extract sign.
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#else
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int32_t xbits = SkFloat2Bits(x);
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int32_t ybits = SkFloat2Bits(y);
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return SkBits2Float((xbits & 0x7FFFFFFF) | (ybits & 0x80000000));
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#endif
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}
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#define sk_float_sqrt(x) sqrtf(x)
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#define sk_float_sin(x) sinf(x)
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#define sk_float_cos(x) cosf(x)
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#define sk_float_tan(x) tanf(x)
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#define sk_float_floor(x) floorf(x)
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#define sk_float_ceil(x) ceilf(x)
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#ifdef SK_BUILD_FOR_MAC
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# define sk_float_acos(x) static_cast<float>(acos(x))
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# define sk_float_asin(x) static_cast<float>(asin(x))
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#else
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# define sk_float_acos(x) acosf(x)
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# define sk_float_asin(x) asinf(x)
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#endif
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#define sk_float_atan2(y,x) atan2f(y,x)
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#define sk_float_abs(x) fabsf(x)
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#define sk_float_mod(x,y) fmodf(x,y)
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#define sk_float_exp(x) expf(x)
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#define sk_float_log(x) logf(x)
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#define sk_float_round(x) sk_float_floor((x) + 0.5f)
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// can't find log2f on android, but maybe that just a tool bug?
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#ifdef SK_BUILD_FOR_ANDROID
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static inline float sk_float_log2(float x) {
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const double inv_ln_2 = 1.44269504088896;
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return (float)(log(x) * inv_ln_2);
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}
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#else
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#define sk_float_log2(x) log2f(x)
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#endif
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#ifdef SK_BUILD_FOR_WIN
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#define sk_float_isfinite(x) _finite(x)
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#define sk_float_isnan(x) _isnan(x)
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static inline int sk_float_isinf(float x) {
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int32_t bits = SkFloat2Bits(x);
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return (bits << 1) == (0xFF << 24);
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}
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#else
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#define sk_float_isfinite(x) isfinite(x)
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#define sk_float_isnan(x) isnan(x)
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#define sk_float_isinf(x) isinf(x)
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#endif
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#define sk_double_isnan(a) sk_float_isnan(a)
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#ifdef SK_USE_FLOATBITS
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#define sk_float_floor2int(x) SkFloatToIntFloor(x)
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#define sk_float_round2int(x) SkFloatToIntRound(x)
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#define sk_float_ceil2int(x) SkFloatToIntCeil(x)
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#else
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#define sk_float_floor2int(x) (int)sk_float_floor(x)
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#define sk_float_round2int(x) (int)sk_float_floor((x) + 0.5f)
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#define sk_float_ceil2int(x) (int)sk_float_ceil(x)
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#endif
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#define sk_double_floor(x) floor(x)
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#define sk_double_round(x) floor((x) + 0.5)
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#define sk_double_ceil(x) ceil(x)
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#define sk_double_floor2int(x) (int)floor(x)
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#define sk_double_round2int(x) (int)floor((x) + 0.5f)
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#define sk_double_ceil2int(x) (int)ceil(x)
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extern const uint32_t gIEEENotANumber;
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extern const uint32_t gIEEEInfinity;
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extern const uint32_t gIEEENegativeInfinity;
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#define SK_FloatNaN (*SkTCast<const float*>(&gIEEENotANumber))
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#define SK_FloatInfinity (*SkTCast<const float*>(&gIEEEInfinity))
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#define SK_FloatNegativeInfinity (*SkTCast<const float*>(&gIEEENegativeInfinity))
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// We forward declare this to break an #include cycle.
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// (SkScalar -> SkFloatingPoint -> SkOpts.h -> SkXfermode -> SkColor -> SkScalar)
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namespace SkOpts { extern float (*rsqrt)(float); }
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// Fast, approximate inverse square root.
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// Compare to name-brand "1.0f / sk_float_sqrt(x)". Should be around 10x faster on SSE, 2x on NEON.
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static inline float sk_float_rsqrt(const float x) {
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// We want all this inlined, so we'll inline SIMD and just take the hit when we don't know we've got
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// it at compile time. This is going to be too fast to productively hide behind a function pointer.
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//
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// We do one step of Newton's method to refine the estimates in the NEON and null paths. No
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// refinement is faster, but very innacurate. Two steps is more accurate, but slower than 1/sqrt.
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//
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// Optimized constants in the null path courtesy of http://rrrola.wz.cz/inv_sqrt.html
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#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE1
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return _mm_cvtss_f32(_mm_rsqrt_ss(_mm_set_ss(x)));
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#elif defined(SK_ARM_HAS_NEON)
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// Get initial estimate.
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const float32x2_t xx = vdup_n_f32(x); // Clever readers will note we're doing everything 2x.
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float32x2_t estimate = vrsqrte_f32(xx);
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// One step of Newton's method to refine.
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const float32x2_t estimate_sq = vmul_f32(estimate, estimate);
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estimate = vmul_f32(estimate, vrsqrts_f32(xx, estimate_sq));
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return vget_lane_f32(estimate, 0); // 1 will work fine too; the answer's in both places.
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#else
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// Perhaps runtime-detected NEON, or a portable fallback.
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return SkOpts::rsqrt(x);
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#endif
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}
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// This is the number of significant digits we can print in a string such that when we read that
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// string back we get the floating point number we expect. The minimum value C requires is 6, but
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// most compilers support 9
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#ifdef FLT_DECIMAL_DIG
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#define SK_FLT_DECIMAL_DIG FLT_DECIMAL_DIG
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#else
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#define SK_FLT_DECIMAL_DIG 9
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#endif
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#endif
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