XY to Screen address (zx-spectrum screen format)

xyhl:
    ; X,Y to screen coordinates (HL > DE)
    ; L as X (pixel)
    ; H as Y (pixel)
    ; return DE as screen address
    ; 120t with CALL & RET
    ld a,h
    and 7
    ld d,a
    ld a,h
    rrca
    rrca
    rrca
    or #40
    and %01011000
    or d
    ld d,a

    ld a,h
    rlca
    rlca
    and #E0
    ld e,a
    ld a,l
    rrca
    rrca
    rrca
    and %00011111
    or e
    ld e,a
    ret