888734 - Some calculation is unpredictable when add a neglect number.

Status: RESOLVED INVALID

(Core :: JavaScript Engine, defect)

Description

[dindog]

These are some results in console:
< 1.3+1.4
> 2.7

< 1.3+(-2)
> -0.7

< 1.3-2.1
> -0.8
Everything seems fines.

< 2.3- 4.23
> -1.9300000000000006
?????

The stable version of Firefox ( 22 ) is affected. Not sure is it reported or not.

Comment 1

[dindog]

...oh, other browsers gave the same results, it's a false alarm? 
Sorry guys. I should have checked that before I reported. 

Would be grateful if there is somebody fill me in why it works like this.

Comment 2

[Till Schneidereit [:till]]

This is not an issue with JavaScript, it's a limitation of how IEEE-754, the floating point format used in pretty much all computer systems, represents numbers.

See[1] and the various resources linked from there for more details.

[1]: http://stackoverflow.com/questions/588004/is-javascripts-floating-point-math-broken