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-rw-r--r--include/private/SkFloatingPoint.h23
-rw-r--r--src/core/SkOpts.cpp2
-rw-r--r--src/core/SkOpts.h3
-rw-r--r--src/opts/SkFloatingPoint_opts.h35
-rw-r--r--src/opts/SkOpts_neon.cpp2
-rw-r--r--tests/MathTest.cpp12
6 files changed, 55 insertions, 22 deletions
diff --git a/include/private/SkFloatingPoint.h b/include/private/SkFloatingPoint.h
index ffed5c0747..f7ee816b12 100644
--- a/include/private/SkFloatingPoint.h
+++ b/include/private/SkFloatingPoint.h
@@ -127,28 +127,20 @@ extern const uint32_t gIEEENegativeInfinity;
#define SK_FloatInfinity (*SkTCast<const float*>(&gIEEEInfinity))
#define SK_FloatNegativeInfinity (*SkTCast<const float*>(&gIEEENegativeInfinity))
-static inline float sk_float_rsqrt_portable(float x) {
- // Get initial estimate.
- int i = *SkTCast<int*>(&x);
- i = 0x5F1FFFF9 - (i>>1);
- float estimate = *SkTCast<float*>(&i);
-
- // One step of Newton's method to refine.
- const float estimate_sq = estimate*estimate;
- estimate *= 0.703952253f*(2.38924456f-x*estimate_sq);
- return estimate;
-}
+// We forward declare this to break an #include cycle.
+// (SkScalar -> SkFloatingPoint -> SkOpts.h -> SkXfermode -> SkColor -> SkScalar)
+namespace SkOpts { extern float (*rsqrt)(float); }
// Fast, approximate inverse square root.
// Compare to name-brand "1.0f / sk_float_sqrt(x)". Should be around 10x faster on SSE, 2x on NEON.
-static inline float sk_float_rsqrt(float x) {
+static inline float sk_float_rsqrt(const float x) {
// We want all this inlined, so we'll inline SIMD and just take the hit when we don't know we've got
// it at compile time. This is going to be too fast to productively hide behind a function pointer.
//
-// We do one step of Newton's method to refine the estimates in the NEON and portable paths. No
+// We do one step of Newton's method to refine the estimates in the NEON and null paths. No
// refinement is faster, but very innacurate. Two steps is more accurate, but slower than 1/sqrt.
//
-// Optimized constants in the portable path courtesy of http://rrrola.wz.cz/inv_sqrt.html
+// Optimized constants in the null path courtesy of http://rrrola.wz.cz/inv_sqrt.html
#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE1
return _mm_cvtss_f32(_mm_rsqrt_ss(_mm_set_ss(x)));
#elif defined(SK_ARM_HAS_NEON)
@@ -161,7 +153,8 @@ static inline float sk_float_rsqrt(float x) {
estimate = vmul_f32(estimate, vrsqrts_f32(xx, estimate_sq));
return vget_lane_f32(estimate, 0); // 1 will work fine too; the answer's in both places.
#else
- return sk_float_rsqrt_portable(x);
+ // Perhaps runtime-detected NEON, or a portable fallback.
+ return SkOpts::rsqrt(x);
#endif
}
diff --git a/src/core/SkOpts.cpp b/src/core/SkOpts.cpp
index 669401b417..28dd1afc71 100644
--- a/src/core/SkOpts.cpp
+++ b/src/core/SkOpts.cpp
@@ -13,6 +13,7 @@
#include "SkBlitRow_opts.h"
#include "SkBlurImageFilter_opts.h"
#include "SkColorCubeFilter_opts.h"
+#include "SkFloatingPoint_opts.h"
#include "SkMatrix_opts.h"
#include "SkMorphologyImageFilter_opts.h"
#include "SkSwizzler_opts.h"
@@ -54,6 +55,7 @@ namespace SkOpts {
// If our global compile options are set high enough, these defaults might even be
// CPU-specialized, e.g. a typical x86-64 machine might start with SSE2 defaults.
// They'll still get a chance to be replaced with even better ones, e.g. using SSE4.1.
+ decltype(rsqrt) rsqrt = sk_default::rsqrt;
decltype(memset16) memset16 = sk_default::memset16;
decltype(memset32) memset32 = sk_default::memset32;
decltype(create_xfermode) create_xfermode = sk_default::create_xfermode;
diff --git a/src/core/SkOpts.h b/src/core/SkOpts.h
index 41ad8ebfe8..1a9820b417 100644
--- a/src/core/SkOpts.h
+++ b/src/core/SkOpts.h
@@ -23,6 +23,9 @@ namespace SkOpts {
// Declare function pointers here...
+ // Returns a fast approximation of 1.0f/sqrtf(x).
+ extern float (*rsqrt)(float);
+
// See SkUtils.h
extern void (*memset16)(uint16_t[], uint16_t, int);
extern void (*memset32)(uint32_t[], uint32_t, int);
diff --git a/src/opts/SkFloatingPoint_opts.h b/src/opts/SkFloatingPoint_opts.h
new file mode 100644
index 0000000000..8b6536ad7f
--- /dev/null
+++ b/src/opts/SkFloatingPoint_opts.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkFloatingPoint_opts_DEFINED
+#define SkFloatingPoint_opts_DEFINED
+
+#include "SkFloatingPoint.h"
+
+namespace SK_OPTS_NS {
+
+#if defined(SK_ARM_HAS_NEON)
+ static float rsqrt(float x) {
+ return sk_float_rsqrt(x); // This sk_float_rsqrt copy will take the NEON compile-time path.
+ }
+#else
+ static float rsqrt(float x) {
+ // Get initial estimate.
+ int i = *SkTCast<int*>(&x);
+ i = 0x5F1FFFF9 - (i>>1);
+ float estimate = *SkTCast<float*>(&i);
+
+ // One step of Newton's method to refine.
+ const float estimate_sq = estimate*estimate;
+ estimate *= 0.703952253f*(2.38924456f-x*estimate_sq);
+ return estimate;
+ }
+#endif
+
+} // namespace SK_OPTS_NS
+
+#endif//SkFloatingPoint_opts_DEFINED
diff --git a/src/opts/SkOpts_neon.cpp b/src/opts/SkOpts_neon.cpp
index dcb057e1fe..9cff2298e4 100644
--- a/src/opts/SkOpts_neon.cpp
+++ b/src/opts/SkOpts_neon.cpp
@@ -12,6 +12,7 @@
#include "SkBlitRow_opts.h"
#include "SkBlurImageFilter_opts.h"
#include "SkColorCubeFilter_opts.h"
+#include "SkFloatingPoint_opts.h"
#include "SkMatrix_opts.h"
#include "SkMorphologyImageFilter_opts.h"
#include "SkSwizzler_opts.h"
@@ -21,6 +22,7 @@
namespace SkOpts {
void Init_neon() {
+ rsqrt = sk_neon::rsqrt;
memset16 = sk_neon::memset16;
memset32 = sk_neon::memset32;
create_xfermode = sk_neon::create_xfermode;
diff --git a/tests/MathTest.cpp b/tests/MathTest.cpp
index de7ad1db78..24e46f3097 100644
--- a/tests/MathTest.cpp
+++ b/tests/MathTest.cpp
@@ -382,15 +382,14 @@ static void unittest_half(skiatest::Reporter* reporter) {
}
-template <typename RSqrtFn>
-static void test_rsqrt(skiatest::Reporter* reporter, RSqrtFn rsqrt) {
+static void test_rsqrt(skiatest::Reporter* reporter) {
const float maxRelativeError = 6.50196699e-4f;
// test close to 0 up to 1
float input = 0.000001f;
for (int i = 0; i < 1000; ++i) {
float exact = 1.0f/sk_float_sqrt(input);
- float estimate = rsqrt(input);
+ float estimate = sk_float_rsqrt(input);
float relativeError = sk_float_abs(exact - estimate)/exact;
REPORTER_ASSERT(reporter, relativeError <= maxRelativeError);
input += 0.001f;
@@ -400,7 +399,7 @@ static void test_rsqrt(skiatest::Reporter* reporter, RSqrtFn rsqrt) {
input = 1.0f;
for (int i = 0; i < 1000; ++i) {
float exact = 1.0f/sk_float_sqrt(input);
- float estimate = rsqrt(input);
+ float estimate = sk_float_rsqrt(input);
float relativeError = sk_float_abs(exact - estimate)/exact;
REPORTER_ASSERT(reporter, relativeError <= maxRelativeError);
input += 0.01f;
@@ -410,7 +409,7 @@ static void test_rsqrt(skiatest::Reporter* reporter, RSqrtFn rsqrt) {
input = 1000000.0f;
for (int i = 0; i < 100; ++i) {
float exact = 1.0f/sk_float_sqrt(input);
- float estimate = rsqrt(input);
+ float estimate = sk_float_rsqrt(input);
float relativeError = sk_float_abs(exact - estimate)/exact;
REPORTER_ASSERT(reporter, relativeError <= maxRelativeError);
input += 754326.f;
@@ -556,8 +555,7 @@ DEF_TEST(Math, reporter) {
unittest_fastfloat(reporter);
unittest_isfinite(reporter);
unittest_half(reporter);
- test_rsqrt(reporter, sk_float_rsqrt);
- test_rsqrt(reporter, sk_float_rsqrt_portable);
+ test_rsqrt(reporter);
for (i = 0; i < 10000; i++) {
SkFixed numer = rand.nextS();
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-01 14:42:53 +0000