Reland "Implement hyperbolic math functions for ES6."

src/harmony-math.js

Index: src/harmony-math.js
diff --git a/src/harmony-math.js b/src/harmony-math.js
index a4d3f2e8a5e9c5936630571644605402dee1199d..2bf33d63f2c81b26263abffea9e931bb9a60008e 100644
--- a/src/harmony-math.js
+++ b/src/harmony-math.js
@@ -47,13 +47,82 @@ function MathTrunc(x) {
 }
 
 
+// ES6 draft 09-27-13, section 20.2.2.30.
+function MathSinh(x) {
+  if (!IS_NUMBER(x)) x = NonNumberToNumber(x);
+  // Idempotent for NaN, +/-0 and +/-Infinity.
+  if (x === 0 || !NUMBER_IS_FINITE(x)) return x;
+  return (MathExp(x) - MathExp(-x)) / 2;
+}
+
+
+// ES6 draft 09-27-13, section 20.2.2.12.
+function MathCosh(x) {
+  if (!IS_NUMBER(x)) x = NonNumberToNumber(x);
+  // Idempotent for NaN and +/-Infinity.
+  if (!NUMBER_IS_FINITE(x)) return x;
+  return (MathExp(x) + MathExp(-x)) / 2;
+}
+
+
+// ES6 draft 09-27-13, section 20.2.2.33.
+function MathTanh(x) {
+  if (!IS_NUMBER(x)) x = NonNumberToNumber(x);
+  // Idempotent for +/-0.
+  if (x === 0) return x;
+  // Returns +/-1 for +/-Infinity.
+  if (!NUMBER_IS_FINITE(x)) return MathSign(x);
+  var exp1 = MathExp(x);
+  var exp2 = MathExp(-x);
+  return (exp1 - exp2) / (exp1 + exp2);
+}
+
+
+// ES6 draft 09-27-13, section 20.2.2.5.
+function MathAsinh(x) {
+  if (!IS_NUMBER(x)) x = NonNumberToNumber(x);
+  // Idempotent for NaN, +/-0 and +/-Infinity.
+  if (x === 0 || !NUMBER_IS_FINITE(x)) return x;
+  if (x > 0) return MathLog(x + MathSqrt(x * x + 1));
+  // This is to prevent numerical errors caused by large negative x.
+  return -MathLog(-x + MathSqrt(x * x + 1));
+}
+
+
+// ES6 draft 09-27-13, section 20.2.2.3.
+function MathAcosh(x) {
+  if (!IS_NUMBER(x)) x = NonNumberToNumber(x);
+  if (x < 1) return NAN;
+  // Idempotent for NaN and +Infinity.
+  if (!NUMBER_IS_FINITE(x)) return x;
+  return MathLog(x + MathSqrt(x + 1) * MathSqrt(x - 1));
+}
+
+
+// ES6 draft 09-27-13, section 20.2.2.7.
+function MathAtanh(x) {
+  if (!IS_NUMBER(x)) x = NonNumberToNumber(x);
+  // Idempotent for +/-0.
+  if (x === 0) return x;
+  // Returns NaN for NaN and +/- Infinity.
+  if (!NUMBER_IS_FINITE(x)) return NAN;
+  return 0.5 * MathLog((1 + x) / (1 - x));
+}
+
+
 function ExtendMath() {
   %CheckIsBootstrapping();
 
   // Set up the non-enumerable functions on the Math object.
   InstallFunctions($Math, DONT_ENUM, $Array(
     "sign", MathSign,
-    "trunc", MathTrunc
+    "trunc", MathTrunc,
+    "sinh", MathSinh,
+    "cosh", MathCosh,
+    "tanh", MathTanh,
+    "asinh", MathAsinh,
+    "acosh", MathAcosh,
+    "atanh", MathAtanh
   ));
 }