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Old 08 January 2016, 18:55   #763
Toni Wilen
WinUAE developer
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 43
Posts: 20,628
Delirium (1991)(Complex)[a][A92#2] in tosec works slightly better (non-a has same problem), less glitches but some still remain.

My guess for the bug is this code sequence:

; enable blitter interrupt
00015256 3b7c 8040 009a           MOVE.W #$8040,(A5, $009a) == $00dff09a
; clear blitter interrupt request
0001525C 3b7c 0040 009c           MOVE.W #$0040,(A5, $009c) == $00dff09c
; set blitter interrupt request
00015262 3b7c 8040 009c           MOVE.W #$8040,(A5, $009c) == $00dff09c
I think this was supposed to "kickstart" blitter interrupt chain but it does it twice if blitter if blitter interrupt request is already active (and it is). Clear should be before enable.
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