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Unified Diff: src/math.js

Issue 59153007: Revert "Implement Math.sin, cos and tan using table lookup and spline interpolation." (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Created 7 years, 1 month ago
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Index: src/math.js
diff --git a/src/math.js b/src/math.js
index 1f7e327582f2ff68099882fc19f9006a3222c527..efab63a186d4f8b924894dad9c1f0be59ef9846a 100644
--- a/src/math.js
+++ b/src/math.js
@@ -79,7 +79,7 @@ function MathCeil(x) {
// ECMA 262 - 15.8.2.7
function MathCos(x) {
- return MathCosImpl(x);
+ return %_MathCos(TO_NUMBER_INLINE(x));
}
// ECMA 262 - 15.8.2.8
@@ -185,7 +185,7 @@ function MathRound(x) {
// ECMA 262 - 15.8.2.16
function MathSin(x) {
- return MathSinImpl(x);
+ return %_MathSin(TO_NUMBER_INLINE(x));
}
// ECMA 262 - 15.8.2.17
@@ -195,7 +195,7 @@ function MathSqrt(x) {
// ECMA 262 - 15.8.2.18
function MathTan(x) {
- return MathSinImpl(x) / MathCosImpl(x);
+ return %_MathTan(TO_NUMBER_INLINE(x));
}
// Non-standard extension.
@@ -204,68 +204,6 @@ function MathImul(x, y) {
}
-var MathSinImpl = function(x) {
- InitTrigonometricFunctions();
- return MathSinImpl(x);
-}
-
-
-var MathCosImpl = function(x) {
- InitTrigonometricFunctions();
- return MathCosImpl(x);
-}
-
-
-function InitTrigonometricFunctions() {
- var samples = 2048; // Table size.
- var pi = 3.1415926535897932;
- var pi_half = pi / 2;
- var inverse_pi_half = 1 / pi_half;
- var two_pi = pi * 2;
- var interval = pi_half / samples;
- var inverse_interval = samples / pi_half;
- var table_sin = new global.Float64Array(samples + 2);
- var table_cos_interval = new global.Float64Array(samples + 2);
-
- %PopulateTrigonometricTable(table_sin, table_cos_interval, samples);
-
- // This implements the following algorithm.
- // 1) Multiplication takes care of to-number conversion.
- // 2) Reduce x to the first quadrant [0, pi/2].
- // Conveniently enough, in case of +/-Infinity, we get NaN.
- // 3) Replace x by (pi/2-x) if x was in the 2nd or 4th quadrant.
- // 4) Do a table lookup for the closest samples to the left and right of x.
- // 5) Find the derivatives at those sampling points by table lookup:
- // dsin(x)/dx = cos(x) = sin(pi/2-x) for x in [0, pi/2].
- // 6) Use cubic spline interpolation to approximate sin(x).
- // 7) Negate the result if x was in the 3rd or 4th quadrant.
- // 8) Get rid of -0 by adding 0.
- MathSinImpl = function(x) {
- var multiple = %_MathFloor(x * inverse_pi_half);
- x = (multiple & 1) * pi_half +
- (1 - ((multiple & 1) << 1)) * (x - multiple * pi_half);
- var double_index = x * inverse_interval;
- var index = double_index | 0;
- var t1 = double_index - index;
- var t2 = 1 - t1;
- var y1 = table_sin[index];
- var y2 = table_sin[index + 1];
- var dy = y2 - y1;
- return (t2 * y1 + t1 * y2 +
- t1 * t2 * ((table_cos_interval[index] - dy) * t2 +
- (dy - table_cos_interval[index + 1]) * t1)) *
- (1 - (multiple & 2)) + 0;
- };
-
- MathCosImpl = function(x) {
- return MathSinImpl(x + pi_half);
- };
-
- %SetInlineBuiltinFlag(MathSinImpl);
- %SetInlineBuiltinFlag(MathCosImpl);
-}
-
-
// -------------------------------------------------------------------
function SetUpMath() {
@@ -338,10 +276,6 @@ function SetUpMath() {
"min", MathMin,
"imul", MathImul
));
-
- %SetInlineBuiltinFlag(MathSin);
- %SetInlineBuiltinFlag(MathCos);
- %SetInlineBuiltinFlag(MathTan);
}
SetUpMath();
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