Xeda's getkey (modified)

getkey:
;;Returns A=scan code, or A=0 and z flag set if no key is pressed
    ld bc,$BF01
    ld a,$40
loop:
    sub $8
    ret z
    out (c),b
    sra b
    in h,(c)
    jp pe,loop
loop2:
    add hl,hl
    ret nc
    dec a
    jr loop2