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base:256_bytes_tune_player

256 bytes tune+player by FTC/HT

Sorry, don't remember what assembler I used to assemble this. Might have been Dreamass by Doc Bacardi/The Dreams.

This tune+player was coded as a compo entry for the Tiny SID #1 competition. The aim was to make a quite long tune rather than something short with fancy instruments.

NOTE: Freshness79 wrote a post on CSDb where he said: “You can cut 2 more bytes by using $032c to “automagically” run your code. This routine gets called at the end of the load process to close all channels ($F32F). It doesn't need to be followed by particular sequences of bytes.”

; Title:  "NewKidOnTheBlock"
; Chip:   6581 C64 used when composing.
; Author: Frantic/Hack'n'Trade

;---------------------------------
; CONSTANTS
;
DEBUG			= 0
NUMBEROFVOICES		= 3	;Using all three Voices
S			= $10	;Song "speed"

;---------------------------------
; ZERO PAGE ADDRESSES
;

TICKCOUNTERS		= $02	;Use zp for tickcounters.. TICKCOUNTERS+0, TICKCOUNTERS+7,
				;TICKCOUNTERS+14 will be used.
DATAPOS			= $03	;Use zp for SONGPOSITIONS... 0, 7, 14.. 
FILTERHI		= $23

;---------------------------------
; CODE
;
	* = $326

        .word start	;Four byte init code. Shamelessly ripped from Alihs entry, who ripped it from Steven 
        .word $f6ed	;Judd... :) Since Alih "ripped" this I guess I could just as well use it too.???
        		;I hope that won't break any competition rules. Ninjas method, used in xxxlarge was
        		;nice too, but still some bytes larger even if one includes the extra code here
        		;needed for raster sync.. 

start:		sei

		ldy #$02	;Set it to $02 so the first incorrectly timed 
				;iteration won't affect anything
		sty FILTERHI	;Init filtersweep to make it a bit more deterministic.

		;Init counters and sonpositions
		lda #(NUMBEROFVOICES-1)*7	;Voice indeX
@initlp:	tax
		sta DATAPOS,x		;Init datapos+0 to 0, datapos+7 to 7 and datapos+14 to 14.
		sty TICKCOUNTERS,x	;y can be anything.. doesn't matter, but now I happen to 
					;init the filter so set it to $01 too
		sec
		sbc #7
		bpl @initlp

;--
; Main player loop		
@outerloop:
@wrast:		cpx $d012	;After the loop, x is a negative number, thus well above $3e 
				;(or whatever the critical raster value is again..)
		bne @wrast	;First iteration won't be correct though, but since the
				;counters are set to 2 initially it doesn't matter.

		#if DEBUG
			lda #1
			sta $d020
			sta $d021
		#endif

		jsr $b5ff	;hijack some BASIC ROM shit to do the filter sweep
					;b5ff looks like this:
					;	inc $23
					;	ldx $23
					;	ldy #$00
					;	rts
		stx $d416	;filter hi

		ldx #(NUMBEROFVOICES-1)*7	;Voice indeX
		;Right here is a good place for Voice specific code, if there is any reason for that.
@innerloop:
		dec TICKCOUNTERS,x
		bne @loopend
		
		;Time for new sound settings, turn gate and oscillator off..
		lda #8
		sta $d404,x

		;Turn on global volume to make sure we'll hear anything at all.
		;Reason for having this code *inside* the loop: 
		;  To make sure the player won't run too fast and get executed
		;  twice on the same rasterline.
		lda #$5f	;Hi-pass + Lo-pass filter on.
		sta $d418
		lda #$a2	;Filter used on middle (melody) voice.
		sta $d417
		
		;Parse data sequence data
		ldy DATAPOS,x
	@newseq:
		iny
		lda @musicdata-1,y	;Get databyte
		bne @nonewseq
		lda @musicdata-0,y	;Get jumpval if it's jumptime
		tay			;..and use new one instead
		bpl @newseq		;This means data may not be larger than $80 bytes
	@nonewseq:
		sty DATAPOS,x
		pha
		and #$0f		;Note value
		tay
		lda @freqhi,y
		sta $d401,x		;Freq hi
		lda @freqlo,y
		sta $d400,x		;Freq lo
		pla
		lsr
		lsr
		lsr
		lsr
		tay
		lda adtab,y
		sta $d405,x
		lda durtab,y
		sta TICKCOUNTERS,x
		lda ctrltab,y
		sta $d404,x
		
@loopend:
		txa
		.byte $cb,7		;axs #7 / sbx #7 / whatever..
		bpl @innerloop
		
		#if DEBUG
			dec $d020
			dec $d021
			jmp @outerloop
		#endif

		bmi @outerloop


;---------------------------------
; "Instruments"
;
; Using AD only to save space. (SR is set to 00 as default)
;
; A pattern is S*8 ticks long, so using "instrument" 5 we
; can represent a whole empty pattern by just one byte in
; the sequence data. At the same time, this format allows
; for changes to the waveform every tick, which means we
; can also make drums and such things. But, not in this 
; tune. Perhaps in the next one..
;
;		       00   01   02   03   04   05   06
@adtab:		.byte $1c, $1b, $cd, $2b, $1a, $00, $ad
@ctrltab:	.byte $11, $11, $21, $21, $21, $00, $21
@durtab:	.byte S*1, S*3, S*6, S*2, S*1, S*8, S*8

;---------------------------------
; Sequence data
;
; Voc0 starts at 0
; Voc1 starts at 7
; Voc2 starts at 14
;
; Note and duration stored in one byte and the byte following a $00 (JP)
; byte is interpreted as the destination of a jump to another place in 
; the data.

@musicdata:
@Voc0start:
	.byte $00 | G4
	.byte $00 | Az4
	.byte $00 | C5
	.byte $00 | D5
	.byte $00 | Dz5
	.byte JP
	.byte <(@Voc0komp-@musicdata)
@Voc1start:
	.byte $20 | D5
	.byte $30 | Dz5
	
	.byte $20 | D5
	.byte $40 | A4
	.byte $40 | Az4
	
	.byte JP
	.byte <(@Voc1melody-@musicdata)
@Voc2start:
	;-
	.byte $50 | 0
	.byte $50 | 0
	.byte $50 | 0
	.byte $50 | 0

	;-
	.byte $50 | 0
@Voc2loop:
	.byte $50 | 0
	.byte $50 | 0
	.byte $20 | C5
	.byte $40 | Dz4
	.byte $40 | F4

	;-
	.byte $50 | 0
	.byte $60 | D5
	.byte $20 | Dz5
	.byte $30 | Az4
	.byte $20 | A4
	.byte $30 | F4
	
	;-
	.byte $60 | G4
	.byte $50 | 0
	.byte $50 | 0
	.byte $60 | C5

	;-
	.byte $50 | 0
	.byte $60 | D5
	.byte $60 | Dz5
	.byte $60 | F5
	
	;-
	.byte $60 | G5
	.byte JP
	.byte <(@Voc2loop-@musicdata)
@Voc0komp:
	.byte $10 | G5

	.byte $00 | D4
	.byte $00 | Fz4
	.byte $00 | A4
	.byte $00 | Az4
	.byte $00 | C5
	.byte $10 | D5

	.byte $00 | Dz4
	.byte $00 | F4
	.byte $00 | G4
	.byte $00 | Az4
	.byte $00 | C5
	.byte $10 | Dz5
	
	.byte $00 | F4
	.byte $00 | A4
	.byte $00 | C5
	.byte $00 | D5
	.byte $00 | Dz5
	.byte $10 | F5

	.byte JP
	.byte <(@Voc0start-@musicdata)

@Voc1melody:
	.byte $20 | C5
	.byte $30 | Az4

	.byte $20 | A4
	.byte $30 | F4
	
	;-
	.byte $60 | G4
	
	.byte $50 | 0

	.byte $20 | F4
	.byte $30 | Dz4

	.byte $20 | F4
	.byte $30 | Dz4

	;-
	.byte $20 | D4
	.byte $30 | Dz4

	.byte $20 | D4
	.byte $30 | Fz4

	.byte $20 | G4
	.byte $30 | Dz4

	.byte $00 | C4
	.byte $00 | Dz4
	.byte $00 | F4
	.byte $00 | G4
	.byte $00 | A4
	.byte $00 | C5
	.byte $00 | G5
	.byte $00 | F5
	
	.byte JP
	.byte <(@Voc1start-@musicdata)

;---------------------------------
;Note freq data
;
; Only using needed notes.

		JP	=  0
		C4	=  1
		D4	=  2
		Dz4	=  3
		;E4	=  2;Not used
		F4	=  4
		Fz4	=  5
		G4	=  6
		;Gz4	=  6;Not used
		A4	=  7
		Az4	=  8
		;B4	=  8;Not used
		C5	=  9
		;Cz5	=  9;Not used
		D5	= 10
		Dz5	= 11
		;E5	= 11;Not used
		F5	= 12
		;Fz5	= 13;Not used
		G5	= 13
		;Gz5	;Not used
		;A5	;Not used
		;Az5	= 14;Not used

@freqlo	= *-1	;-1 to exclude the corresponding first byte (in @freqhi) used as a "wrap flag"
		.byte $77
		.byte $61,$e1
		.byte $f7,$8f,$30
		.byte $8f,$4e
		.byte $ef
		.byte $c3,$c3
		.byte $ef
		.byte $60

@freqhi:
		.byte $00 ;WRAP
		.byte $07
		.byte $08,$08
		.byte $09,$0a,$0b
		.byte $0c,$0d
		.byte $0e
		.byte $10,$11
		.byte $13
		.byte $16

base/256_bytes_tune_player.txt · Last modified: 2015-04-17 04:30 (external edit)