[webkit-dev] Question about Floating-point operations base SH4 JIT

talking1239 at gmail.com talking1239 at gmail.com
Thu Aug 2 00:02:14 PDT 2012

My platform use the  little-endian.   


BGs/Felix Shi

At 2012-08-02 14:51:48,"Filip Pizlo" <fpizlo at apple.com> wrote:
What is the endianness of your platform?  I think that the big endian code in JavaScriptCore may have rotted.

This smells to me like the tag and payload getting flipped around, which might happen if there are parts of the code that are assuming little endian and your hardware is big endian.


On Aug 1, 2012, at 11:47 PM, talking1239 at gmail.com wrote:


I have test with follow case, and cann't get correct reslut. I find that Floating-point operations  is error, and I don't know where shold start to fixed this question. so if anybody can give some information for which function i should to check. 

Any help explaining this would be much appreciated!

My Compiler:MSVS



Javascript code of test case

function jitTestCode() {

  var tmp = -1*0;

  debug("tmp:" + tmp); 

  var result = tmp + 1;

  debug("The result should be 1,result:" + result);   //print

  var item1 =  result - 1;

  debug("The item1 should be 0,item1:" + item1); //print

  var item2 =  result - 2;

  debug("The item2 should be -1,item2:" + item2); //print



And the log information are:

[CONSOLE-DEBUG]Message is :'tmp:0'

[CONSOLE-DEBUG]Message is :'The result should be 1,result:0.0078125'

[CONSOLE-DEBUG]Message is :'The item1 should be 0,item1:0'

[CONSOLE-DEBUG]Message is :'The item2 should be -1,item2:-0.0078125'


BGs/Felix Shi

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