.z80
	external NBits,BitCnt,WB,InByte

getbts:	ld	HL,0	;Results here
	ld	A,(NBits)
	ld	C,A	; C := NBits
	ld	A,(BitCnt)
	cp	C
	jr	NC,ok	;BitCnt>=NBits

	ld	B,A	;B := BitCnt
	ld	A,C	;A := NBits
	sub	B	;A := NBits - BitCnt
	ld	(NBits),A
	ld	A,(WB)
	call	shl	;WB shl BitCnt
	push	HL	;intermediate result
	call	InByte	;new Byte in L
	ld	A,(NBits)
	ld	B,A	;B := NBits
	ld	A,8	;
	SUB	B	;A := 8 - NBits
	ld	(BitCnt),A
	ld	A,L	;New byte
	pop	HL
	call	shl	;WB shl NBits
	ld	(WB),A
	ret

ok:	ld	B,C	;B := NBits
	sub	B	;A := BitCnt - NBits
	ld	(BitCnt),A
	ld	A,(WB)
	call	shl
	ld	(WB),A
	ret

shl:	sla	A	;MSB in Carry
	rl	L
	djnz	shl
	ret

	end	getbts