;	SineML.dsm
;	L. Stewart August 24, 1982  12:54 PM

C_CODE	SEGMENT

ASSUME CS:C_CODE, DS:C_DATA

; Generate Sine wave
; int Sine(initialphase, &SineCB);
; where SineCB is a pointer to the control block
;  and Sine returns the final phase
; The control block has the fields
;	destination pointer
;	sample count
;	frequency
;	sinetable

_Sine	PROC	NEAR
	MOV	DI,[BX]		; destination
	MOV	DX,CX		; initial phase
	MOV	CX,[2+BX]	; count (bytes)
	OR	CX,CX
	JZ	sdone
	MOV	SI,[4+BX]	; frequency
	MOV	BX,[6+BX]	; sinetable
	CLD			; increment DI on STOSB
sloop:
	ADD	DX,SI		; phase increment
	MOV	AL,DH		; upper 8 bits of phase are table index
	XLATB			; fetch from table
	STOSB			; store into destination and increment
	LOOP	sloop		; decrement count and loop
sdone:
	MOV	BX,DX
	RET
_Sine	ENDP

PUBLIC	_Sine

C_CODE	ENDS
	END