1. ver 4.0 and_bits question

  • Posted by bernie Mar 31, 2009
  • 1033 views 
-- test.exw  program using SVN 1539 on WIN98 
 
include std/math.e 
 
atom x 
 
x = 16777220 
? and_bits(x,#F) 
 
x = #1000004 
? and_bits(x,#F) 
 
x = -16777220 
? and_bits(x,#F) -- <-- why does this return a different result 
 
x = -#1000004 
? and_bits(x,#F) -- <-- why does this return a different result 
 
x = #81000004    -- <-- note high bit set 
? and_bits(x,#F) 
 
if getc(0) then 
-- pause 
end if 
 
-- end program
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2. Re: ver 4.0 and_bits question

  • Posted by mattlewis (admin) Mar 31, 2009
  • 1062 views

Bernie,

FYI, this isn't a 4.0 issue. It has to do with how euphoria interprets hex numbers. This should help with some insights: 

procedure examine( atom x ) 
	printf(1, "\nDecimal: %d\nHex:     %x\nx & 0xf: %x\n", {x,x, and_bits( x, #f)}) 
end procedure 
 
examine( 16777220 ) 
examine( #1000004 ) 
examine(-16777220 ) 
examine( -#1000004 ) 
examine( #81000004 )

This code produces: 

Decimal: 16777220 
Hex:     1000004 
x & 0xf: 4 
 
Decimal: 16777220 
Hex:     1000004 
x & 0xf: 4 
 
Decimal: -16777220 
Hex:     FEFFFFFC 
x & 0xf: C 
 
Decimal: -16777220 
Hex:     FEFFFFFC 
x & 0xf: C 
 
Decimal: 2164260868 
Hex:     81000004 
x & 0xf: 4
Matt

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