[stella] Assymetrical Maze 2LK... help?

["J Parlee" <lost_monkey@xxxxxxxxxxxx>]

Greetings All!

I have put the project I last posted about (summer 2002) on the back burner
to try something a little easier, and hopefully something I will be able to
finish.

I am working on a port of KC Munckin from the O2 to the 2600.

I've spent a few hours on it now, and I have come to a point of frustration
with the assymetrical playfield and a 2LK... I've dug through the DIG and
the Stella list archives and I cannot find any info on how to keep the
second playfield writes from bleeding onto the first on the second line...

I've attached the bin to demonstrate the way the playfield is behaving.  For
the record, the playfield displays fine (assymetrically) if the 2nd line of
the kernel is commented out...

Here is the text of the kernel (everything is in odd places right now and
the cycle count is useless as I've been shuffling things around...)

     LDY #90
     STY ScanLine

ScanLoop

     TYA                       ;[57]+2 = 59
     TAX                       ;[61]+2 = 63
     STA     WSYNC
     LDA     #00            ;waste
     LDA     PFData0,X     ;[3] +4 = 7
     STA     PF0                 ;[7] +3 = *13*   < 23
     LDA     PFData1,X           ;[13]+4 = 17
     STA     PF1                 ;[14]+3 = *20*  < 29
     LDA     PFData2,X           ;[17]+4
     STA     PF2                 ;[21]+3 = *27*  < 40
     LDA     PFRData0,X   ;[24]+4 = 28
     STA     PF0                   ;[28]+3 = *31*
     LDA     PFRData1,X  ;[31]+4 = 35
     STA     PF1                   ;[35]+3 = *38*
     LDA     PFRData2,X  ;[38]+4 = 42
     STA     PF2
     LDY     ScanLine
     TYA
     SEC                       ;[56]+2 = 58
     SBC     yPos0  ;[58]+3 = 61
     ADC     P0Size  ;[]+3 = 73
     STA     WSYNC
     BCC     SkipDraw  ;[73]+2 = 75 3
     TAY                       ;[75]+2 = 79
     LDA     KcData1,Y  ;[79]+4 = 83
     STA     GRP0  ;[0]+3 = *3*
Next
     DEC     ScanLine
     LDY     ScanLine
     BNE     ScanLoop  ;[54]+2 = 56
     STA     WSYNC  ;Finish this scanline.
     LDY     #10
DrawScore
     LDA     KcData1,Y
     STA     GRP0
     LDA     #00
     STA     PF0
     STA     PF1
     STA     PF2
     STA     WSYNC
     DEY
     BPL     DrawScore
EndScreen
     LDA     #2
     STA     VBLANK

Any insights or common knowledge and sarcasm would be appreciated.  No
public berating could be too harsh.. ;)

Thanks!

Jason

Attachment: kc.bin
Description: Binary data