<rdar://problem/7909395> Math in JavaScript is inaccurate on iOS

By defalut IEEE754 denormal support is disabled on iOS;
turn it on.

Reviewed by Filip Pizlo.

* jsc.cpp:
(main):
    - clear the appropriate bit in the fpscr.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@115523 268f45cc-cd09-0410-ab3c-d52691b4dbfc

diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
index ec354bb..df935de 100644 (file)
--- a/Source/JavaScriptCore/ChangeLog
+++ b/Source/JavaScriptCore/ChangeLog
@@ -1,3 +1,16 @@
+2012-04-27  Gavin Barraclough  <barraclough@apple.com>
+
+        <rdar://problem/7909395> Math in JavaScript is inaccurate on iOS
+
+        By defalut IEEE754 denormal support is disabled on iOS;
+        turn it on.
+
+        Reviewed by Filip Pizlo.
+
+        * jsc.cpp:
+        (main):
+            - clear the appropriate bit in the fpscr.
+
 2012-04-27  Michael Saboff  <msaboff@apple.com>
 
         Memory wasted in JSString for non-rope strings

diff --git a/Source/JavaScriptCore/jsc.cpp b/Source/JavaScriptCore/jsc.cpp
index 1786e09..0a702d0 100644 (file)
--- a/Source/JavaScriptCore/jsc.cpp
+++ b/Source/JavaScriptCore/jsc.cpp
@@ -72,6 +72,11 @@
 #include <QDateTime>
 #endif
 
+#if PLATFORM(IOS)
+#include <fenv.h>
+#include <arm/arch.h>
+#endif
+
 using namespace JSC;
 using namespace WTF;
 
@@ -445,6 +450,14 @@ int jscmain(int argc, char** argv, JSGlobalData*);
 
 int main(int argc, char** argv)
 {
+#if PLATFORM(IOS)
+    // Enabled IEEE754 denormal support.
+    fenv_t env;
+    fegetenv( &env );
+    env.__fpscr &= ~0x01000000u;
+    fesetenv( &env );
+#endif
+
 #if OS(WINDOWS)
 #if !OS(WINCE)
     // Cygwin calls ::SetErrorMode(SEM_FAILCRITICALERRORS), which we will inherit. This is bad for