Page Comparison

IN:  A = timeout in centiseconds (-1, no timeout)
OUT: Fc = 0, success and A = key codekey code

OUT:  Fc=0, always
             Fz = 1, converted, A = ISO character
        Fc = 1, failure and AFz = RC_TIME0, timeout elapsed
not converted, A unchanged

Registers changed after return:
     ....DEHL/IXIY same
     AFBC..../.... different