;---------------------------------------------------------------------------
; * Subject: [stella] Christmas program
; * From: Piero Cavina
; * Date: Thu, 25 Dec 1997 23:28:47 +0100
; * Reply-To: stella@biglist.com
;---------------------------------------------------------------------------
; chrdem01.asm
; Piero Cavina's "it's Christmas and I can't leave my 2600 alone demo v 0.1"
; 25/12/1997
processor 6502
VSYNC = $00
VBLANK = $01
WSYNC = $02
NUSIZ0 = $04
NUSIZ1 = $05
COLUP0 = $06
COLUP1 = $07
COLUPF = $08
COLUBK = $09
CTRLPF = $0A
REFP0 = $0B
REFP1 = $0C
PF0 = $0D
PF1 = $0E
PF2 = $0F
RESP0 = $10
RESP1 = $11
RESM0 = $12
RESM1 = $13
RESBL = $14
AUDC0 = $15
AUDF0 = $17
AUDV0 = $19
AUDC1 = $16
AUDF1 = $18
AUDV1 = $1A
GRP0 = $1B
GRP1 = $1C
ENAM0 = $1D
ENAM1 = $1E
ENABL = $1F
HMP0 = $20
HMP1 = $21
HMM0 = $22
HMM1 = $23
HMBL = $24
RESMP0 = $28
RESMP1 = $29
HMOVE = $2A
HMCLR = $2B
CXCLR = $2C
CXM0P = $30
CXP1FB = $33
SWCHA = $0280
SWACNT = $0281
SWCHB = $0282
SWBCNT = $0283
INTIM = $0284
TIM8T = $0295
TIM64T = $0296
CXPPMM = $7
INPT0 = $8
INPT3 = $A
INPT4 = $3C
COUNT = $80
ORG $F000
CLD
LDX #$FF
TXS
INX
TXA
LPC: STA VSYNC,X
INX
BNE LPC
STA SWBCNT
STA SWACNT
MAIN:
LDX #0
LDA #$02
STA WSYNC
STA WSYNC
STA WSYNC
STA VSYNC
STA WSYNC
STA WSYNC
STA WSYNC
STX VSYNC
; -------------------------
LDA #$35
STA TIM64T
; -------------------------
STA WSYNC
LDX #7
LPP:
DEX
BPL LPP
STA RESM1
STA RESM0
; -------------------------
; Finisici il tempo di Vblank
LF20C: LDA INTIM
BNE LF20C
STA WSYNC
STA VBLANK
STA HMCLR
; -------------------------
; Kernel
LDA #$FF
STA ENAM1
STA ENAM0
INC COUNT
; try to uncomment these lines..
; LDA COUNT
; STA NUSIZ0
; STA NUSIZ1
LDX #191
LK:
TXA
ADC COUNT
ASL
ASL
STA HMM1
EOR #$FF
STA HMM0
STA COLUP1
STA COLUP0
STA WSYNC
STA HMOVE
DEX
BNE LK
; -------------------------
STX ENAM1
STX ENAM0
STA WSYNC
LDA #$02
STA WSYNC
STA VBLANK
; -------------------------
LDA #$2A
STA TIM64T
; ------------------------
OVRS:
LDA INTIM
BNE OVRS
JMP MAIN
ORG $FFFC
.byte $00,$F0,$00,$F0