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paraj · 06 November 2021, 16:21

Just a quick sanity check. I'm disassembling parts of RSI MegaDemo and it contains this small function, that the author clearly intended to wait for the blitter to be finished (it's called before blitter registers are updated):

Code:

00000a6e 0839 000e 00df f002      btst.b #$000e,$00dff002
00000a76 66f6                     bne.b #$f6 == $00000a6e
00000a78 4e75                     rts

It actually checks BLTEN though, and things just happen to work regardless, right?

(The copper isn't touching any blitter registers/dmacon, so it doesn't look like a "clever" way to synchronize with that).

06 November 2021, 16:21	#1
paraj Registered User Join Date: Feb 2017 Location: Denmark Posts: 1,104	BTST.B with memory Just a quick sanity check. I'm disassembling parts of RSI MegaDemo and it contains this small function, that the author clearly intended to wait for the blitter to be finished (it's called before blitter registers are updated): Code: 00000a6e 0839 000e 00df f002 btst.b #$000e,$00dff002 00000a76 66f6 bne.b #$f6 == $00000a6e 00000a78 4e75 rts It actually checks BLTEN though, and things just happen to work regardless, right? (The copper isn't touching any blitter registers/dmacon, so it doesn't look like a "clever" way to synchronize with that).