title	Module from library BASE_1 : RAND16
	name	('RAND16')
	maclib	baselib.lib

; 16-bit Random Number Generator

; This generator is based on similar method but gives much better results.
; It was taken from an old ZX Spectrum game and slightly optimised.

; Compilation by Werner Cirsovius

; ENTRY	None

; EXIT	Reg HL holds pseudo-random number, period 65536

	entry	Rand16

Rand16:
	ld	de,$-$		; Seed is usually 0
	ld	a,d
	ld	h,e
	ld	l,253
	or	a
	sbc	hl,de
	sbc	a,0
	sbc	hl,de
	ld	d,0
	sbc	a,d
	ld	e,a
	sbc	hl,de
	jr	nc,Rand
	inc	hl
Rand:
	ld	(Rand16+1),hl
	ret

	end