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player.asm @ 1

Last change on this file since 1 was 1, checked in by svn, 6 years ago
Import initial
File size: 1.4 KB

Rev	Line
[1]	1	****************************************************************
	2	****************************************************************
	3	(main)player.asm
	4
	5	ORG $9000
	6
	7	PSHS U,X,DP,B,A,CC
	8
	9	ORCC #$50
	10	LDA #$FB
	11	ANDA $E7CF
	12	STA $E7CF
	13	LDA #$3F
	14	STA $E7CD
	15	LDA #$04
	16	ORA $E7CF
	17	STA $E7CF
	18	LDX #$A000
	19	STX pos_song
	20	BRA loop
	21
	22	PULS U,X,DP,B,A,CC
	23	RTS
	24
	25	fine fcb 0
	26	pos_song fcb $A0,$00
	27
	28
	29
	30
	31	****************************************************************
	32	*
	33	*
	34	* bank 5
	35	* read pattern info
	36	* switch to bank
	37	* read pattern data
	38	* output to DAC
	39	* advance in pattern
	40	* if necessary, advance in song
	41	* try to be less than 64, fixed timing
	42	*
	43	****************************************************************
	44
	45	loop
	46	LDB #05
	47	STB $E7E5
	48	LDX pos_song
	49	LDB ,x+
	50	LDA ,x+
	51	TFR x,y
	52	* switch to pattern bank
	53	STB $E7E5
	54	CLRB
	55	ADDA #$A0
	56	TFR D,X
	57	LDB fine
	58	ABX
	59	LDA ,x
	60	STA $E7CD
	61	INCB
	62	CMPB #160
	63	BEQ end_chunk
	64	STB fine
	65	BRA wait1
	66	wait1 BRA wait2
	67	wait2 BRA end
	68	end_chunk
	69	CLR fine
	70	STY pos_song
	71
	72	end
	73	* 85 cycles for now ... wait 43
	74	MUL
	75	MUL
	76	MUL
	77	NOP
	78	NOP
	79	BRA pre_end
	80	pre_end BRA loop
	81
	82
	83
	84	****************************************************************
	85	*
	86	* Attente de la VBL
	87	*
	88	****************************************************************
	89	VSYNC
	90	VSYNC_1
	91	TST $E7E7
	92	BPL VSYNC_1
	93	VSYNC_2
	94	TST $E7E7
	95	BMI VSYNC_2
	96
	97	RTS
	98
	99

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