東南大學(xué)信息學(xué)院微機(jī)實(shí)驗(yàn)報告九

1、實(shí)驗(yàn)九一、實(shí)驗(yàn)?zāi)康氖煜は到y(tǒng)功能調(diào)用INT21H的有關(guān)功能1. 編寫時鐘程序二、實(shí)驗(yàn)任務(wù)1. 執(zhí)行時鐘程序時，屏幕上顯示提示符“：隨即顯示時間并不停地計時。2. 當(dāng)有鍵盤按下時，立即停止計時，返回三、源程序DATASEGMENTBUFFERDB11DB?DB10DUPDATAENDSCODESEGMENTASSUMECS:CODE,DS:DATAOUTCLK:MOVAX,DATAMOVDS,AXMOVDL,':'MOVAH,2INT21HMOVDX,OFFSETBUFFERMOVAH,0AH;INT21HMOVBX,OFFSETBUFFER+2MOVAL,BX;CMPAL,03A

2、HJAEERROR1CMPAL,02FHJBEERROR1ANDAL,0FHMOVBX,ALINCBXMOVAL,BXANDAL,0FHMOVBX,ALINCBXINCBXMOVAL,BX;ANDAL,0FHMOVBX,ALINCBX”，由鍵盤輸入當(dāng)前時、分、秒值，即DOS輸入字符串時針，ASCII碼轉(zhuǎn)非壓縮BCD分針XX:XX:XXMOVAL,BXANDAL,0FHMOVBX,ALINCBXINCBXMOVAL,BX;秒針ANDAL,0FHMOVBX,ALINCBXMOVAL,BXANDAL,0FHMOVBX,ALMOVBX,OFFSETBUFFER+2CALLTOBCDMOVCH,ALAD

3、DBX,3CALLTOBCDMOVDH,ALMOVDH,ALADDBX,3CALLTOBCDMOVDL,ALCMPCH,24HJAEERRORCMPDH,60HJAERRORCMPDL,60HJAERRORERROR1:MOVAH,4CHINT21HAGAIN:CALLDELAYMOVAL,DLADDAL,1DAAMOVDL,ALCMPAL,60HJAERRORJNEDISPYMOVDL,0MOVAL,DHADDAL,1DAAMOVDH,ALCMPAL,60H時針，兩位非壓縮分針，兩位非壓縮秒針，兩位非壓縮秒針加1分針BCD轉(zhuǎn)換成兩位壓縮BCDBCD轉(zhuǎn)換成兩位壓縮BCDBCD轉(zhuǎn)換成兩位壓縮BC

4、DJAERRORJNEDISPYMOVDH,0MOVAL,CHADDAL,1時針DAA;MOVCH,ALCMPAL,24HJAEERRORJNEDISPYMOVCH,0ERROR:MOVDL,0MOVDH,0MOVCH,0DISPY:MOVBX,OFFSETBUFFERMOVAL,0DHMOVBX,ALINCBXMOVAL,0MOVBX,ALINCBXMOVAL,CHCALLTRANINCBXMOVAL,':'MOVBX,ALINCBXMOVAL,DHCALLTRANINCBXMOVAL,':'MOVBX,ALINCBXMOVAL,DLCALLTRANINCBX

5、MOVAL,'$'MOVBX,ALPUSHBXPUSHCXPUSHDXMOVDX,OFFSETBUFFERMOVAH,9INT21HMOVAH,06HMOVDL,0FFHINT21HPOPDXPOPCXPOPBXJNEGOJMPAGAINGO:MOVAH,4CHINT21HTOBCDPROC;兩位非壓縮BCD轉(zhuǎn)換成壓縮MOVAL,BXMOVCL,4SHLAL,CLORAL,BX+1RETTOBCDENDPTRANPROC;BCD轉(zhuǎn)ASCIIMOVCL,ALSHRAL,1SHRAL,1SHRAL,1SHRAL,1ORAL,30HMOVBX,ALINCBXMOVAL,CLANDAL,0FHORAL,30HMOVBX,ALRETTRANENDPDELAYPROCPUSHCXPUSHAXMOVAX,0FFFFHFIR:MOVCX,02FFFHGOON:DECCXJNEGOONDECAXJNEFIRPOPAXPOPCXRETDELAYENDPCODEENDSENDOUTCLK四、思考題時鐘程序中存在誤差嗎？若有誤差，其來源在何處？如何進(jìn)行誤差矯正