Re: [stella] Syncing without WSYNC

Subject: Re: [stella] Syncing without WSYNC
From: Chris Wilkson <ecwilkso@xxxxxxx>
Date: Fri, 31 Aug 2001 01:10:16 -0400 (EDT)
On Thu, 30 Aug 2001, B. Watson wrote:

> This is a case where I'm trying to do so much in one scan line that
> I can't afford the 3 cycles for the STA WSYNC... The loop was 75 cycles,
> including the DEY;BNE top_loop at the end, I changed one of my STA GRP0's to
> a STA $2000+GRP0 to make it eat one more cycle, bringing me up to 76..

Using STA.W GRP0 will force the assembler to use a 2 byte address instead of
zero page mode.  Makes the code a bit easier to read.  :)

> Of course, the last time through the loop, the BNE won't branch, so I'll be at
> the 75th cycle of the last scanline... Slowly, I'm learning this stuff :)

WHAHAHAHA!!!!!  There's never any end!  Ok, ok...I've been hacking on the
interlaced video thing again, so I'm a bit crazed at the moment.  But I
did manage to get both Field 0 and Field 1 to be recognizable.  (Anyone
who starts with "How to Draw a Playfield" is only seeing Field 1.)  I
just haven't gotten the pair to interlace yet.


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