title	Module from library BASE_3 : SGNIN
	name	('SGNIN')
	maclib	baselib.lib

; Convert signed ASCII decimal string to hex number

; Copyright (C)	Werner Cirsovius
;		Hohe Weide 44
;		D-20253 Hamburg
;		Tel.: +49-40-4223247

;		Version 1.1, August 1986

; ENTRY DE points to string
;	B holds end marker of string
;	(usually zero or $)

; EXIT	HL holds hex number
;	Carry set on overflow or illegal digit

	entry	sgnin

	extrn	skpblk,neghl,decin

sgnin:
	call	skpblk		; No leading blanks
	ld	a,(de)		; Test sign
	inc	de
	cp	'-'
	jr	z,dinmin
	cp	'+'
	jr	z,dinu
	dec	de
dinu:
	ld	a,false
	jr	din???
dinmin:
	ld	a,true
din???:
	ld	(dinsin),a	; Save sign
	call	decin		; Get number
	ret	c		; Aha, any error
	ld	a,(dinsin)
	cp	false		; Test unsigned
	ret	z
	ld	a,h
	rla			; Test MSB
	jp	nc,neghl
	ret			; It's overflow

	dseg

dinsin:
	ds	1

	end