GDT_WRITE
gdt_enc16(gccb->gc_cmd + GDT_CMD_OPCODE, GDT_WRITE);
gdt_enc16(gccb->gc_cmd + GDT_CMD_OPCODE, GDT_WRITE);
opcode = (*cmdp == WRITE_6 || *cmdp == WRITE_10) ? GDT_WRITE : GDT_READ;
if ((gdt->sc_state & GDT_SHUTDOWN) && opcode == GDT_WRITE)