title	Module from library BASE_1 : MULTIP
	name	('MULTIP')
	maclib	baselib.lib

; Multiply unsigned numbers

; Written by	G.Reichborn-Kjennerud
;		Tandberg-Data A/S
;		POB 9, Korsvoll, Oslo 8
;		Norway
;		Published in BYTE, June 1983

; Modified by	Werner Cirsovius
;		Hohe Weide 44
;		D-20253 Hamburg
;		Tel.: +49-40-4223247

;		Version 1.1, August 1986

; ENTRY DE,HL hold multiplier
;	One of which must be an 8 bit number

; EXIT	HL holds product
;	Carry set on overflow

	entry	multip

multip:
	xor	a
	or	h		; Find zero high byte
	jr	z,found
	xor	a
	or	d		; 2nd must be zero
	scf
	ret	nz
	ex	de,hl
found:
	ld	a,l		; Get multiplicand
	ld	hl,0		; Clear result
	and	a
next:
	rra			; Find odd or even
	jr	nc,even
	add	hl,de		; Add multiplier
	ret	c		; Error
even:
	and	a		; Test end
	ret	z
	ex	de,hl
	add	hl,hl
	ex	de,hl
	jr	nc,next
	ret

	end