Re: [cc65] tgi interrupts?

From: Ullrich von Bassewitz <>
Date: 2009-09-09 16:50:45
Karri Kaksonen wrote:
> In all my programs I have a VBL interrupt handler in order to swap
> tgi_drawpage and tgi_showpage at a time when the user won't notice the
> change.
> Somehow it would be nice to include this service to the cc65 libraries.
> Perhaps a separate tgi_utils.s ?

I don't like the idea of having separate platform dependent code outside the

Did you know that the driver can receive interrupts? There's an IRQ vector in
the driver that - when it is not zero - is called on each interrupt.
Prerequisite is that the startup code sets up an IRQ handler that calls
callirq. So you could move tgi_swap into the driver. 

The frame counter should probably get replaced by a separate function called
in the IRQ. It is then also possible to implement a clock() function. Maybe
the two can go into one module?

Once the IRQ handler calls callirq, new IRQ functions can be simply declared
with .interruptor.



Ullrich von Bassewitz                        
To unsubscribe from the list send mail to with
the string "unsubscribe cc65" in the body(!) of the mail.
Received on Wed Sep 9 16:52:44 2009

This archive was generated by hypermail 2.1.8 : 2009-09-09 16:52:47 CEST