Changeset 35639 in webkit for trunk/JavaScriptCore/kjs/JSNumberCell.h

Timestamp:

Aug 8, 2008, 2:48:10 AM (17 years ago)

Author:

[email protected]

Message:

Improve performance of arithmetic operators

Reviewed by Cameron Zwarich

Added a fast (non-virtual) mechanism to determine if a non-immediate JSValue*
is a JSNumberCell. We then use this to allow improved specialisation in many
arithmetic operators. SunSpider reports a 2.5% progression overall, with greater
than 10% progressions on a number of arithmetic heavy tests.

File:

• trunk/JavaScriptCore/kjs/JSNumberCell.h (modified) (2 diffs)

trunk/JavaScriptCore/kjs/JSNumberCell.h

@@ -59 +59 @@
         virtual JSObject* toThisObject(ExecState*) const;
         virtual JSValue* getJSNumber();
+        int32_t fastToInt32() const;
+        uint32_t fastToUInt32() const;
 
         void* operator new(size_t size, ExecState* exec)
@@ -147 +149 @@
     }
 
+    inline int32_t JSNumberCell::fastToInt32() const
+    {
+        if (m_value >= -2147483648.0 && m_value < 2147483648.0)
+            return static_cast<int32_t>(m_value);
+        bool scratch;
+        return JSValue::toInt32SlowCase(m_value, scratch);
+    }
+
+    inline uint32_t JSNumberCell::fastToUInt32() const
+    {
+        if (m_value >= 0.0 && m_value < 4294967296.0)
+            return static_cast<uint32_t>(m_value);
+        bool scratch;
+        return JSValue::toUInt32SlowCase(m_value, scratch);
+    }
+
     ALWAYS_INLINE JSValue* JSValue::toJSNumber(ExecState* exec) const
     {