[A83] Re: variable horizontal line routine?
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[A83] Re: variable horizontal line routine?
At 16:03 2001-06-01, you wrote:
>At 14:47 2001-06-01, you wrote:
> >copybytes:
> > ld (hl),a
> > inc hl
> > ld a,$ff ;write $ff to all the other bytes
> > djnz copybytes
>
>
>ld (hl),$ff doesn't exist?
>
>if it doesn't you should anyway put ld a,$ff outside of the loop and do an
>extra ld (hl),a, otherwise it is a slowdown.
>we are optimizing for speed here, not size.
And the first partially filled byte, should be or:ed with the graphbuf, or
it would erase pixels it shouldn't erase.
I forgot about timeings too, the loop should be
ld a,$ff
loop:
inc hl
ld (hl),a
djnz loop
not useing ld (hl),$ff, for one pass this loop is slower, but on an avarage
it is faster.
///Olle
References: