up vote 5 down vote favorite

According to the documentation I have ("Hardware" by J.Schimanski) after setting the copper list COP1LCx under $dff080 it should be started by writing an arbitrary value into COPJMP1 under $dff088. However my copper list works "automatically" without the latter step. What is the right way of doing it? Do I need this starting step?

I use Amiga 500 with ECS.

share|improve this question
up vote 5 down vote accepted

The Copper list is started automatically with every vertical sync. If you need it to start at some other time you need to write to COPJMP1.

share|improve this answer
  • 1
    Can you give me an example of "at some other time"? – Adam Boczek Dec 28 '17 at 12:39
  • 3
    Well, for example you could build separate Copper lists/viewports for several screens you'd want to display simultaneously (below each other). Without merging the separate viewport lists to a single, larger one, you could write each start address to COP1LC and then write to COPJMP1 to switch to that viewport. It's a bit like an unconditional JMP for the Copper, while writing to COP1LC alone just primes the vector for the next run. – Zac67 Dec 28 '17 at 12:55

Your Answer

 

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.