mirror of
https://github.com/sehugg/8bitworkshop.git
synced 2024-12-24 09:30:45 +00:00
90 lines
2.3 KiB
Plaintext
90 lines
2.3 KiB
Plaintext
|
|
processor 6502
|
|
include "vcs.h"
|
|
include "macro.h"
|
|
include "xmacro.h"
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
|
|
seg.u Variables
|
|
org $80
|
|
|
|
Temp .byte
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
|
|
seg Code
|
|
org $f000
|
|
|
|
Start
|
|
CLEAN_START
|
|
lda #0
|
|
sta Temp
|
|
|
|
NextFrame
|
|
VERTICAL_SYNC
|
|
|
|
TIMER_SETUP 37
|
|
inc Temp
|
|
TIMER_WAIT
|
|
|
|
TIMER_SETUP 213
|
|
|
|
lda Temp
|
|
and #$7f
|
|
jsr WaitForScanline
|
|
sta COLUBK
|
|
lda #180
|
|
jsr WaitForScanline
|
|
lda #0
|
|
sta COLUBK
|
|
lda #192
|
|
jsr WaitForScanline
|
|
jmp TimerDone
|
|
|
|
TimerDone
|
|
lda #0
|
|
sta COLUBK
|
|
|
|
TIMER_SETUP 30
|
|
TIMER_WAIT
|
|
jmp NextFrame
|
|
|
|
align $10
|
|
WaitForScanline subroutine
|
|
ldy INTIM ; Fetch timer value
|
|
.Wait
|
|
cpy INTIM
|
|
beq .Wait ; Wait for it to change
|
|
sta WSYNC ; Sync with scan line
|
|
cmp Timer2Scanline,y
|
|
bcs WaitForScanline
|
|
rts
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
|
|
align $100
|
|
Timer2Scanline
|
|
.byte 215, 0,214,213,212,211,210, 0,209,208,207,206,205,204, 0,203
|
|
.byte 202,201,200,199, 0,198,197,196,195,194, 0,193,192,191,190,189
|
|
.byte 188, 0,187,186,185,184,183, 0,182,181,180,179,178, 0,177,176
|
|
.byte 175,174,173,172, 0,171,170,169,168,167, 0,166,165,164,163,162
|
|
.byte 0,161,160,159,158,157,156, 0,155,154,153,152,151, 0,150,149
|
|
.byte 148,147,146, 0,145,144,143,142,141,140, 0,139,138,137,136,135
|
|
.byte 0,134,133,132,131,130, 0,129,128,127,126,125,124, 0,123,122
|
|
.byte 121,120,119, 0,118,117,116,115,114, 0,113,112,111,110,109,108
|
|
.byte 0,107,106,105,104,103, 0,102,101,100, 99, 98, 0, 97, 96, 95
|
|
.byte 94, 93, 92, 0, 91, 90, 89, 88, 87, 0, 86, 85, 84, 83, 82, 0
|
|
.byte 81, 80, 79, 78, 77, 76, 0, 75, 74, 73, 72, 71, 0, 70, 69, 68
|
|
.byte 67, 66, 0, 65, 64, 63, 62, 61, 60, 0, 59, 58, 57, 56, 55, 0
|
|
.byte 54, 53, 52, 51, 50, 0, 49, 48, 47, 46, 45, 44, 0, 43, 42, 41
|
|
.byte 40, 39, 0, 38, 37, 36, 35, 34, 0, 33, 32, 31, 30, 29, 28, 0
|
|
.byte 27, 26, 25, 24, 23, 0, 22, 21, 20, 19, 18, 0, 17, 16, 15, 14
|
|
.byte 13, 12, 0, 11, 10, 9, 8, 7, 0, 6, 5, 4, 3, 2, 0, 1
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; Epilogue
|
|
org $fffc
|
|
.word Start
|
|
.word Start
|