> Well, you could also change your set up of your ISRs (Interrupt
> Service Routine) with your line interrupts (r#19). First of all, disable
> the V_BLANK interrupt, so you are left with only the line interrupts
> from r#19.
But I still have to set VDP(18) back to its original value at line 212, so
that won't be of any use...
> Secondly, make s#2 (status register) standard (set r#15 to
> 2), so you can check very fast if the VDP commands are finished. Make
> sure, though, that you still read out s#0 to clear the IRQ signal.
I've already done that (this way, I also won't need to disable the
interrupts when testing the TR-flag before executing a VDP-command.
By the way, wasn't the screensplit-int-flag located in s#1???
> Preferably, at the *end* of each interrupt, so you have a quick response
> time to the IRQ. Especially if you also set the address to jump to for
> the ISR at the next line interrupt. So you ISR starts with
>
> ld hl,(ISR_vector)
> jp (hl)
>
> and ends with
>
> setreg 15,0
> inreg
> setreg 15,2
> setreg 19,line_x
> ld hl,ISR_x
> ld (ISR_vector),hl
> reti
Oh... yes!
I always test the statusregister, but this is also possible!!!
However, it will give trouble if there are other interrupts generated, like
interrupts of the MoonSound...
> So, how does this help you? You can simulate the V_BLANK interrupt by
> setting r#19 to 212 after the line interrupt at line 160. The nice thing
> is that you can also change r#19 also to 230 or even to 240 and the
> interrupt is still granted! This gives you more time to complete your
> VDP commands.
Ah... so that gives me more time to copy between the two interrupts...
Great idea!!!
> Or you can forget about the second line interrupt alltogether. Execute
> the large copies from line 160 onwards and change r#18 when you are sure
> (some of) the large copies are finished *and* that you are somewhere in
> the black border (the VDP is displaying lines 212 and beyond). This
> might requiring some timing, but it should also work.
Hmmm hmmm... I'll think 'bout that.
Hey! Thanks, this is great!
Maybe it's a good idea to compile some booklet filled with all kinds of tips
like this... I still have some in stock... I would really like to read such
a book... (Book, not webpage).
~Grauw
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