portio.asm

一个cpu的vhdl语言程序。非常好的 一个cpu的vhdl语言程序。非常好的

ldi acc,#F0h stm acc,#20h ; #20H = 0 (counter variable) stacc port all_over: call delay1_sec ; delay for 1 sec ldm acc,#20h ; get count value oracci #F0h ; set LE high stacc port andacci #EFh ; set LE low stacc port oracci #F0h stacc port ; set LE back high ldm acc,#20h addacci #01h ; increment count stm acc,#20h cmpacci #10h jne check_input ; if 10h, set to zero ldi acc,#F0h stm acc,#20h check_input: ldacc port ; get port state into acc andacci #80h ; mask all but MSB je its_zero ldi acc,#F1h stacc port ldi acc,#D1h stacc port ldi acc,#F1h jmp all_over its_zero: ldi acc,#F0h stacc port ldi acc,#D0h stacc port ldi acc,#F0h jmp all_over delay1_sec: push acc ldi acc,#ffh yy: call delay1_ms subacci #01h cmpacci #00h jne yy pop acc ret delay1_ms: push acc ldi acc,#ffh xx: subacci #01h cmpacci #00h cmpacci #00h cmpacci #00h jne xx pop acc ret END