本例為單字節(jié)二進(jìn)制數(shù)(0X20)轉(zhuǎn)換為非壓縮BCD 碼,存在0X25,0X24,0X23 中,0X25 為百位,0X23 為個(gè)位。

main: MOV a,@0xa4 ;賦值

MOV 0x20,a

MOV 0x21,a

MOV 0x22,a

MOV a,@0x0 ;0x23,0x24,0x25 單元清0

MOV 0x23,a

MOV 0x24,a

MOV 0x25,a

MOV a,@0x64 ;對(duì)100 的個(gè)數(shù)計(jì)數(shù)

MOV 0x26,a

MOV a,@0x25 ;百位存在0x25 中

MOV 0x04,a

call a0 ;調(diào)計(jì)數(shù)子程

MOV a,@0x0a ;對(duì)10 的個(gè)數(shù)計(jì)數(shù)

MOV 0x26,a

dec 0x04 ;個(gè)位存在0x24 中

call a0

MOV a,0x22 ;除去百位,十位,余下的即個(gè)位,存入0x23

MOV 0x23,a

self: jmp self

a0: ;計(jì)數(shù)子程

MOV a,0x26

sub 0x22,a

jbs 0x03,2

jmp a1

inc 0x00 ;無(wú)余數(shù)則對(duì)應(yīng)位加1

MOV a,@0x0 ;0x21 與0x22 在返回時(shí)應(yīng)保持相同

MOV 0x21,a

ret

a1: jbs 0x03,0 ;小于則跳a2

jmp a2

inc 0x00 ;大于則計(jì)數(shù)值加1

MOV a,0x22

MOV 0x21,a ;將0x22 保存到0x21 中

jmp a0 ;跳回a0 繼續(xù)計(jì)數(shù)

a2: MOV a,0x21 ;0x21 中保存的減之前的數(shù)據(jù),此時(shí)恢復(fù)到0x22

MOV 0x22,a

ret

eop