Re: SX-clocks (another one)

From: silverdr_at_wfmh.org.pl
Date: Sun, 5 May 2013 12:35:52 +0200
Message-Id: <B10B46CD-7E09-4252-8211-AFA215ED29F2@wfmh.org.pl>
On 2013-05-04, at 20:46, Michał Pleban wrote:

> But probably to use the $D012 register, you would need to turn the
> display on - this is also possibly invasive.

As Segher Boessenkool already mentioned - that one is always available for polling. No need to change or set anything up. Therefore counting 30 full rasters should be as easy as:

	ldx #$1e
:	bit SCROLY	; or even lda SCROLY
	bpl :-
:	bit SCROLY
	bmi :-
	dex
	bne :--

without any preparatory steps.

And with a php/pla I can even test the I flag cheaply ;-)

-- 
SD!
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Received on 2013-05-05 11:00:34

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