int32 ReadB (int32 va)
{
int32 pa, data;

pa = relocR (va);                                       /* relocate */
if (ADDR_IS_MEM (pa))
    return (va & 1? M[pa >> 1] >> 8: M[pa >> 1]) & 0377;
if (pa < IOPAGEBASE) {                                  /* not I/O address? */
    setCPUERR (CPUE_NXM);
    ABORT (TRAP_NXM);
    }
if (iopageR (&data, pa, READ) != SCPE_OK) {             /* invalid I/O addr? */
    setCPUERR (CPUE_TMO);
    ABORT (TRAP_NXM);
    }
return ((va & 1)? data >> 8: data) & 0377;
}