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digarok/deatertweeter.txt

Created March 8, 2021 14:47
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deatertweeter.txt
* Disassembly of @deater object tweet https://twitter.com/deater78/status/1368790980237791232
* by @65816guy / digarok/ Dagen Brock
00/00E7: 20 D8 F3 JSR F3D8 ; HGR2 -- set hi-res, page2, full graphics
00/00EA: 8A TXA
00/00EB: 20 11 F4 JSR F411 ; HPOS2 - positions hi-res cursor without plotting
; (A) = Y-coordinate, (Y,X) = X-coordinate
00/00EE: A2 01 LDX #01
00/00F0: A0 F0 LDY #F0
00/00F2: 20 5D F6 JSR F65D ; XDRAW - Draws a shape inverting dots (eor/xor) on screen.
; (A) = rotation, (Y,X) = address of the shape table
00/00F5: F0 F7 BEQ 00EE {-09}
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digarok commented Mar 8, 2021

From @deater:

the code loads at $E7 so that the the $20 from the JSR also acts as the SCALE size without having to load/store it

you can point the shape table anywhere in memory, I tried out a bunch of locations until I found one that looked cool, but there are probably better ones

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