;-------------------------bcdout routine begins--------------------------+
; from BLUEBOOK OF ASSEMBLY ROUTINES FOR IBM PC & XT.
;         page : 66
;
; NAME BCDOUT
; ROUTINE FOR conversion from BCD to ASCII decimal
;
; FUNCTION: This routine converts a 36-digit number sstored in BCD form
; to ASCII decimal form which is sent to the std I/O device.
;
; INPUT: Upon entry a 36-digit number is stored in an 18-byte BCD buffer
; called BCDBUFF in the DATAS data segment.
;
; OUTPUT: A string of ASCII digits representing a decimal number is
; stored in a buffer called TBUFF and then sent out through a standard
; output device.
;
; REGISTERS USED:  No registers are modified.
; SEGMENTS REFERENCED:  DATAS is a data segment containing BCDBUFF
; and TBUFF.
;
; ROUTINES CALLED:  STDOUT
; SPECIAL NOTES: None
;
; ROUTINE FOR CONVERSION FROM BCD TO ASCII DECIMAL
;
bcdout	proc	far
;
	push	ds		; save registers
	push	si
	push	dx
	push	cx
	push	ax
;
; set up a data segment
	mov	ax,datas	; point to data segment
	mov	ds,ax
;
	mov	cx,18		; for a count of 18
	lea	si,bcdbuff	; point to bcd buffer
	add	si,17		; point to end of bcd buffer
	mov	dh,0		; clear flag for leading zeros
;
bdcout1:
	push	cx		; save count
	mov	al,[si]		; get BCD byte
	dec	si		; and point to next
	mov	dl,al		; save it
;
; upper digit
	mov	cl,4		; for a count of four
	rol	al,cl		; rotate byte
	and	al,0Fh		; just the digit
	or	dh,al		; leading zeros?
	jz	bcdout2		; if so skip digit
	add	al,30h		; make it ASCII
	call	stdout		; send it
;
bcdout2:
	pop	cx		; restore count
	cmp	cx,1		; last digit ?
	jnz	bcdout3		; skip if not
	mov	dh,0FFh		; set flag if so
;
bcdout3:
	push	cx		; save count
;
	mov	al,dl		; get byte back
;
; lower digit
	and	al,0Fh		; just the digit
	or	dh,al		; leading zeros?
	jz	bcdout4		; if so skip digit
	add	al,30h		; make is ASCII
	call	stdout		; send it
;
bcdout4:
;
	pop	cx		; restore loop count
	loop	bcdout1
;
	pop	ax		; restore registers
	pop	cx
	pop	dx
	pop	si
	pop	ds
	ret			; return
;
bcdout	endp
;-------------------------bcdout routine ends---------------------------+