lisa_sound_framework.asm

                       ;-----------------------------------------
                       ;  Adapted from the original Lisa ROM listing 
		       ;  https://www.apple.asimov.net/documentation/applelisa/AppleLisa-BootROMListing.pdf
                       ;    D0 = desired frequency ($00 - $AA)
                       ;    D1 = duration (0 = .5 msec)
                       ;    D2 = volume (0,2,4,...,E)
                       ;    D3 = pulse train shape as a string of 8 bits
                       ;-----------------------------------------

		ORG $800

VIA1BASE	EQU	$00FCDD81
ORB1		EQU	$0
DDRB1		EQU	$4
T2CL1		EQU	$10
SHR1		EQU	$14
ACR1		EQU	$16
DISKROM		EQU	$FCC031
SLOTMR		EQU	5

; approximate pitches

d_sharp_3	EQU	$CC
e_3		EQU	$C2	
f_3		EQU	$B7
f_sharp_3	EQU	$AA    ; 186Hz, should be 185
g_3		EQU	$A1     ; 196 Hz, close enough
g_sharp_3	EQU	$98    ; 207 Hz, close enough
a_3		EQU	$90    ; 219, should be 220
a_sharp_3	EQU	$87    ; 234, should be 233
b_3		EQU	$80
c_4		EQU	$78
c_sharp_4	EQU	$70
d_4		EQU	$6B    ; 295 Hz, should be closer to 293.7
d_sharp_4	EQU	$65
e_4		EQU	$60
f_4		EQU	$59
f_sharp_4	EQU	$55	;369Hz
g_4		EQU	$50
g_sharp_4	EQU	$4B	; 419 Hz, should be 415
a_4		EQU	$47     ; 442 Hz, should be 440
a_sharp_4	EQU	$43	; 468 Hz, should be 466
b_4		EQU	$3F	; 497 Hz, should be 494
c_5		EQU	$3C	; 517 Hz, should be 523
c_sharp_5	EQU	$38	; 553 Hz, should be 554
d_5		EQU	$35	; 585 Hz, should be 587
d_sharp_5	EQU	$32     ; 622 Hz, close enough
e_5		EQU	$2F	; 663 Hz, should be 659
f_5		EQU	$2C	; 
f_sharp_5	EQU	$2A 	; 737 Hz, should be 740
g_5		EQU	$27	; 796 Hz, very far should be 784
g_sharp_5	EQU	$25	; 
a_5		EQU	$23	; 884 Hz, should be 880
pause		EQU	$0      ; 0 frequency is silence

; approximate note values at 120 bpm
sixtyfour	EQU	$40
thirtytwo	EQU	$80
sixteen		EQU	$100
eight		EQU	$200
eightplus	EQU	eight+sixteen
quarter 	EQU	$400
half		EQU	$800
whole		EQU	$1000

MUSIC
	MOVE.W #%11110000,D3 ; pulse train shape
	MOVE.w #e_5,D0       ; pitch
	MOVE.w #quarter,D1   ; duration
	MOVE.W #$2,D2        ; volume
	BSR	TONE2
	MOVE.w #d_5,D0
	MOVE.w #eight,D1
	MOVE.W #$4,D2
	BSR	TONE2
	MOVE.W #%01011101,D3
	MOVE.w #c_5,D0
	MOVE.w #sixteen,D1
	MOVE.W #$6,D2
	BSR	TONE2
	

TONE    MOVEM.L  A0/A4/D4,-(SP)   ;save regs
  	BSR      TONE2            ;go do tone
  	LEA      zero,A4
  	BRA.S    TONE2
  	RTS
zero
        MOVEM.L (SP)+,A0/A4/D4  ;restore and exit
        RTS

; separate entry point for call without memory usage
TONE2   MOVEA.L  #VIA1BASE,A0   ;set VIA ptr
        ORI.B   #$0E,DDRB1(A0)  ;set volume bits for output
        ANDI.B  #$F1,ORB1(A0)   ;clear and then
        OR.B    D2,ORB1(A0)     ; set volume bits
        ANDI.B  #$E3,ACR1(A0)   ;clear shift mode bits
        ORI.B   #$10,ACR1(A0)   ;set shift reg for continuous rotate

; check system type
        TST.B   DISKROM         ;test for Lisa 1 board                  CHG014
        BPL.S   three		 ;no changes if yes                      CHG014
        BTST    #SLOTMR,DISKROM ;else check if slow timers              CHG029
        BNE.S   three		 ;skip if yes                            CHG029
        MOVE.B  D0,D4           ;else adjust input parm                 CHG014
        LSR.B   #2,D4           ; by factor of .25                      CHG014
        ADD.B   D4,D0           ;                                       CHG014

three   MOVE.B  D0,T2CL1(A0)    ;set frequency
        MOVE.B  D3,SHR1(A0)     ;set pulse train

; Do time delay -  enter with count in D1 (about .5 msec per count)
one 	MOVE.W  #$00D0,D4       ;set delay constant
two	DBF     D4,two
        DBF     D1,one

SILENCE ANDI.B  #$E3,ACR1(A0)   ;disable tone
        RTS                     ;and return