Add sk_float_rsqrt with SSE + NEON fast paths.
Current numbers:
N4:
running bench [640 480] math_fastIsqrt NONRENDERING: cmsecs = 3.12
running bench [640 480] math_slowIsqrt NONRENDERING: cmsecs = 4.82
running bench [640 480] math_sk_float_rsqrt NONRENDERING: cmsecs = 1.99
Desktop:
running bench [640 480] math_fastIsqrt NONRENDERING: cmsecs = 0.89
running bench [640 480] math_slowIsqrt NONRENDERING: cmsecs = 0.94
running bench [640 480] math_sk_float_rsqrt NONRENDERING: cmsecs = 0.09
Haven't found any other benches where this is a significant effect yet.
BUG=
R=reed@google.com
Author: mtklein@google.com
Review URL: https://codereview.chromium.org/60083014
git-svn-id: http://skia.googlecode.com/svn/trunk@12203 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/core/SkPoint.h b/include/core/SkPoint.h
index b94f730..caf2650 100644
--- a/include/core/SkPoint.h
+++ b/include/core/SkPoint.h
@@ -216,13 +216,10 @@
* Return true if the computed length of the vector is >= the internal
* tolerance (used to avoid dividing by tiny values).
*/
- static bool CanNormalize(SkScalar dx, SkScalar dy)
-#ifdef SK_SCALAR_IS_FLOAT
- // Simple enough (and performance critical sometimes) so we inline it.
- { return (dx*dx + dy*dy) > (SK_ScalarNearlyZero * SK_ScalarNearlyZero); }
-#else
- ;
-#endif
+ static bool CanNormalize(SkScalar dx, SkScalar dy) {
+ // Simple enough (and performance critical sometimes) so we inline it.
+ return (dx*dx + dy*dy) > (SK_ScalarNearlyZero * SK_ScalarNearlyZero);
+ }
bool canNormalize() const {
return CanNormalize(fX, fY);
@@ -252,6 +249,14 @@
*/
bool setLength(SkScalar x, SkScalar y, SkScalar length);
+ /** Same as setLength, but favoring speed over accuracy.
+ */
+ bool setLengthFast(SkScalar length);
+
+ /** Same as setLength, but favoring speed over accuracy.
+ */
+ bool setLengthFast(SkScalar x, SkScalar y, SkScalar length);
+
/** Scale the point's coordinates by scale, writing the answer into dst.
It is legal for dst == this.
*/
@@ -316,7 +321,6 @@
* Returns true if both X and Y are finite (not infinity or NaN)
*/
bool isFinite() const {
-#ifdef SK_SCALAR_IS_FLOAT
SkScalar accum = 0;
accum *= fX;
accum *= fY;
@@ -327,12 +331,6 @@
// value==value will be true iff value is not NaN
// TODO: is it faster to say !accum or accum==accum?
return accum == accum;
-#else
- // use bit-or for speed, since we don't care about short-circuting the
- // tests, and we expect the common case will be that we need to check all.
- int isNaN = (SK_FixedNaN == fX) | (SK_FixedNaN == fX));
- return !isNaN;
-#endif
}
/**