[MacRuby-devel] [MacRuby] #748: 32bit Number Limit and Conversion

[MacRuby]

#748: 32bit Number Limit and Conversion
-----------------------------+----------------------------------------------
 Reporter:  lp@…             |       Owner:  lsansonetti@…        
     Type:  defect           |      Status:  new                  
 Priority:  major            |   Milestone:  MacRuby 0.7          
Component:  MacRuby          |    Keywords:  32bit number         
-----------------------------+----------------------------------------------
 there seems to be a bug in the 32bit release of 0.6 with numbers

 arch -arch i386 macirb --simple-prompt
 >> 0x44485250
 # reality check
 => 1145590352
 >> NSNumber.numberWithInt(0x44485250)                              # then
 see all 32 NSNumber are weird...
 => 71848528
 >> NSNumber.numberWithFloat(0x44485250)
 => 1145590272.0
 >> NSNumber.numberWithInt(1145590352)
 => 71848528
 >> NSNumber.numberWithFloat(1145590352)
 => 1145590272.0

 versus:

 arch -arch x86_64 macirb --simple-prompt
 >> 0x44485250
 # reality check
 => 1145590352
 >> NSNumber.numberWithInt(0x44485250)
 => 1145590352
 >> NSNumber.numberWithFloat(0x44485250)
 => 1145590400.0
 >> NSNumber.numberWithInt(1145590352)
 => 1145590352
 >> NSNumber.numberWithFloat(1145590352.0)                      # this is
 weird again...
 => 1145590400.0

 to look a bit further, the bug turning point seems to be here for the
 32bit release:

 >> NSNumber.numberWithInt(536870910)
 => 536870910
 >> NSNumber.numberWithInt(536870911)
 => 536870911
 >> NSNumber.numberWithInt(536870912)
 => -536870912
 >> NSNumber.numberWithInt(536870913)
 => -536870911

 and here in the 64 bit:

 >> NSNumber.numberWithInt(2147483646)
 => 2147483646
 >> NSNumber.numberWithInt(2147483647)
 => 2147483647
 >> NSNumber.numberWithInt(2147483648)
 => -2147483648
 >> NSNumber.numberWithInt(2147483649)
 => -2147483647


 also an other detail:

 32bit turning point:
 >> 536870911 / 16
 => 33554431

 64bit turning point:
 >> 2147483647 / 64
 => 33554431

-- 
Ticket URL: <http://www.macruby.org/trac/ticket/748>
MacRuby <http://macruby.org/>