title	Module from library HIFLOAT_4 : FLFRAC
	name	('FLFRAC')
	maclib	baselib.lib

; Get fraction of number

; Copyright (C)	Werner Cirsovius
;		Hohe Weide 44
;		D-20253 Hamburg
;		Tel.: +49-40-4223247
;		Version 1.0 January 1989

; ENTRY	Number to be fractioned in regs DE,HL

; EXIT	Regs DE,HL hold fraction of number

	entry	?flfrac

	ext	?fladd

?flfrac:
	ld	a,h		; Test zero number
	or	a
	ret	z
	jp	p,pos.frac	; .. and negative one
neg.frac:	
	res	sign,h		; Reset bit
	call	pos.frac	; Get fraction
	bit	zero,h		; Test bit
	ret	z
	set	sign,h		; Set if positive result
	push	hl		; Save number
	push	de
	ld	hl,4000h	; Load 1.0
	ld	d,l
	ld	e,l
	call	?fladd		; Build 1.0-FRACTION
	ret
pos.frac:	
	bit	sign,d		; Test exponent MSB
	ret	nz
	ld	b,d		; Get it
	inc	b
	ld	a,e
mant.shf:	
	add	a,a		; Shift mantissa
	adc	hl,hl
	djnz	mant.shf
	ld	d,-1
	res	sign,h		; Reset MSB
	ld	e,a
mant.norm:	
	bit	zero,h		; Check normalize bit
	ret	nz
	dec	d		; Fix exponent
	sla	e		; .. and mantissa
	adc	hl,hl
	jr	nz,mant.norm
	inc	e
	dec	e
	jr	nz,mant.norm
	ld	d,e		; Return LSB, it's the exponent
	ret

	end