Re: A92: testing bits of byte


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Re: A92: testing bits of byte



Eric wrote:
> 
> i need to test the bits of a byte and jump to some place if its one or
> some other place if its zero.
> i tried using btst.b but that just caused crashes. i was thinking about
> this instead:
> 
> and #%0000001,d0  ; i think this modifies d0?
> cmp.b #%0000001,d0 ; (if not this won't work)
> bne place2   ; means its zero
> bra place1   ; means its one
> 
> will that work?  am i using btst wrong?
> i tried:
> btst.b #1,d0
> bne
> bra
> ..
> 
> does btst change d0?

No, but it returns the opposite values, i.e. bne will jump if the bit
was set.


References: