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: