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8bitworkshop/presets/vcs/skeleton.dasm

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2016-12-16 01:21:51 +00:00
processor 6502
include "vcs.h"
include "macro.h"
include "xmacro.h"
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Variables segment
seg.u Variables
org $80
Temp .byte
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Code segment
seg Code
org $f000
Start
CLEAN_START
NextFrame
lsr SWCHB ; test Game Reset switch
bcc Start ; reset?
; 1 + 3 lines of VSYNC
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VERTICAL_SYNC
; 37 lines of underscan
TIMER_SETUP 37
TIMER_WAIT
; 192 lines of frame
TIMER_SETUP 192
TIMER_WAIT
; 29 lines of overscan
TIMER_SETUP 29
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TIMER_WAIT
; total = 262 lines, go to next frame
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jmp NextFrame
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Epilogue
org $fffc
.word Start ; reset vector
.word Start ; BRK vector