copied from ~yamasaki/verilog/slite/

window over/underflow handling routine of ROM should be used instead of that of RAM ( loaded program ) for monitor 

check points:
	1: window unf/ovf trap routine 
	2: sp and fp low enough?
	3: read without DQM_1, char write with DQM_1 of B
	4: cache_on?
	5: ram_test passed?
	6: serial initialized correctly?
