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Flavioweb
Registered: Nov 2011
Posts: 447 |
Screen on or screen off... this is the question!
I have this code
.C:c000 78 SEI
.C:c001 A9 80 LDA #$80
.C:c003 CD 12 D0 CMP $D012
.C:c006 D0 FB BNE $C003
.C:c008 A9 00 LDA #$00
.C:c00a 8D 11 D0 STA $D011
.C:c00d 2C 11 D0 BIT $D011
.C:c010 10 FB BPL $C00D
.C:c012 A9 80 LDA #$80
.C:c014 CD 12 D0 CMP $D012
.C:c017 D0 FB BNE $C014
.C:c019 A9 1B LDA #$1B
.C:c01b 8D 11 D0 STA $D011
.C:c01e 60 RTS
Using Vice, if i set a break point at $C019, i would expect to have the screen turned off here... but is not so.
I have only a black "fld" line in the middle of the screen
Is it a correct behavior? |
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Fresh
Registered: Jan 2005
Posts: 101 |
Here it's working fine in both X64 and X64SC (Version 3.1).
If you're using VICE on Windows you may have to trigger a redraw (ie cover the emulator window with another app and then remove it).
Don't know if this apply to other OSes. |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
I'm using x64sc 3.1 r34148 (GTK+) compiled from sources on openSUSE Tumbleweed...
Better double check my codes on RH. |
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Han
Registered: Apr 2017
Posts: 8 |
Are you trying to disable the screen only partially? Unfortunately that's not possible. |
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JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: Are you trying to disable the screen only partially? Unfortunately that's not possible.
It most definetly is by doing a reverse side border opening. But it requires cycle precise timing per raster line closed, i.e. totally useless. |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
Quote: Are you trying to disable the screen only partially? Unfortunately that's not possible.
No... I'm just testing when the video is turned off.
Since, as written in Vic Article, DEN bit is checked somewhere in raster line $30, i'm expecting that clearing it at line $80 and then wait for line $80 again, in next frame, screen should be off.
But i can't see this in Vice.
In the "next frame" i can just see some DMA artifacts... but screen still ON (since, at least, at the end of second frame).
So i'm thinking if this "frame" is part of the normal behavior of the VIC or it happen just in (my) Vice. |
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Han
Registered: Apr 2017
Posts: 8 |
Oh, now I see what you are doing. And Fresh is right: you have to force a redraw. When I grab the emulator window and move it, the upper half of the screen is suddenly disabled. |
