Compucolor.org – Virtual Media

Listing of file='SND.MAC;04' on disk='vmedia/asm_utility_routines-sideA-sector.ccvf'

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
;	SND - SOUND ROUTINE FOR THE AY-3-8910
;
;	VALUES ON ENTRY:
;	   THE EXTERNAL VARIABLES PITCH AND AMP MUST BE
;	SET BEFORE A CALL TO THIS ROUTINE.
;
;	NOTE: SNDSET MUST BE CALLED PRIOR TO THIS ROUTINE
;		IN ORDER TO SET UP THE CHIP. TO STOP THE
;		SOUND OUTPUT, CALL SNDOFF.
;
SNDADR	EQU	30H	;ADDRESS REGISTER ON AY-3-8910,
			;   AND READ FROM CHIP
SNDDAT	EQU	31H	;LOAD (WRITE) DATA INTO AY-3-8910

	EXTRN	PITCH,AMP

	ENTRY	SND

SND:	DI
	LHLD	PITCH
	MVI	A,1
	OUT	SNDADR
	MOV	A,H
	OUT	SNDDAT
	XRA	A
	OUT	SNDADR
	MOV	A,L
	OUT	SNDDAT
	MVI	A,8
	OUT	SNDADR
	LDA	AMP
	OUT	SNDDAT
	EI
	RET

	END