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Old 25 February 2014, 14:30   #85
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Join Date: Aug 2004
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Originally Posted by Toni Wilen View Post
It is OCS/ECS confirmed, perhaps this hardware feature was fixed in AGA (and emulation should only do this if OCS/ECS, need some more tests).

I just ECS re-tested by booting OS3.9 with A3000, set interlaced max overscan, last scanline is blank.

This needs to be emulated, there is at least one demo that sets display ending vertical line higher than last line, waits for last line, starts doing some copperlist modifications, if display DMA is not disabled, DMA will steal cycles from CPU and code will take too long and display has glitches..
It's surprising no-one at Commodore ever noticed it. In interlaced modes, the last three lines are blanked (not two like I said earlier). Or at least, that's what happens with WinUAE 2.7.1b9...

In fact I just noticed something strange about this. Using a PAL/ECS config boot BorderSpritesTest.adf which I attached to this post. Double-click MaxOverscanECS.pre.
Double-click PAL_HighResLaced.pre. Notice the bottom three lines are blank (colour 00).
Double-click NTSC_HighResLaced.pre. Only the bottom one line is blank.
Double-click PAL_HighResLaced.pre again. Now the bottom five lines are blank!
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