PureBasic Forums - English

Posted: **Wed Oct 18, 2006 11:46 pm**

Just messing about with PB but I've noticed this:

a.l=b.f*c.l+1.5+9
Debug a ;debugs 10
a.l=b.f*c.l+1.5+90
Debug a ;debugs 92

Why is 1.5 being rounded to 1 in the first case, but 2 in the second?

Posted: **Thu Oct 19, 2006 3:59 pm**

The multiplication has nothing do to with it:

a.l = b.f + 1.5 + 9
Debug a ;debugs 10

a.l = b.f + 1.5 + 10
Debug a ;debugs 12

Purebasic correctly adds the float constants together:

PokeL(@a.f, 1093140480)
Debug a ; 10.5

PokeL(@a.f, 1094189056)
Debug a ; 11.5

Conclusion: The FPU FISP instruction (store a float number to an integer) uses banker's rounding mode.

Floats bug, or feature?