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Old 03 October 2009, 12:02   #48
Toni Wilen
WinUAE developer
 
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 49
Posts: 26,502
Quote:
Originally Posted by yaqube View Post
Hi Toni,

The problem observed by you is caused by an "unusable" cycle for the copper. Since the copper uses every other cycle and every scan line has odd number of memory access cycles (at least in PAL) there is a situation when two accesses could happen back to back. In such a case one of these cycles is "blocked".
Thanks, this explains the "problem" perfectly. I guess this could be called some kind of copper's real "starting point"?

EDIT: this can explain few demos that have copper waits like 32DF FFFE + move. (which should be the exact position that causes 1 cycle delay and also slowing down the blitter by 1 cycle)

Last edited by Toni Wilen; 03 October 2009 at 17:13.
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