Z80 opcodes

[Archi Schekochikhin]

  Hello, MSX users!

  I am interesting about Z80 opcodes with prefixes DD/FD (ix/iy).
Who are know about Z80's behaviour in case of using this prefixes with
undeclared commands? Particularly I am interesting about commands like

    PREF ld l,a |   PREF ld h,a

may be in this case we will have access to low/high bytes of ix/iy?

  May be in MSX-society there are real Z80-MSXes (not emulated) and
it's possible to test the Z80 for this opcodes, or anybody simple know
the answer?

    With best regards.
    Archi.