计算机硬件基础课后答案

2-18(1)1278H+3469H=0001001001111000+0011010001101001=0100011011100001SF=0ZF=0AF=1PF=1CF=0OF=0(2)54E3H-27A0H=0101010011100011+1101100001100000=10010110101000011SF=0ZF=0AF=0PF=0CF=0OF=0当进行16位或8位加或减运算时，若最高位产生进位或借位时，将CF置1，否则为0，当进行带符号数补码运算时，运算结果超出了机器所能表示的数值范围，就产生溢出，将OF置1，否则OF置0，即OF用来表示有符号数运算的溢出，而CF则用来表示无符号数运算的溢出。2-24答:存储慢速设备（存储器或I/O设备）的数据时，必须插入等待周期TW来延长总线周期，插入TW多少取决于CPU完成独立操作所需时间。2-26D读存储器00001写存储器010104-5DATASEGSEGMENTMY1BDB‘PERSONALCOMPUTER’MY2BDB20MY3BDB14HMY4BDB00010100BMY5WDW20DUP(?)MY6WEQU100DATASEGENDS4-6(1)BX=(2);(2)AL=(2);(3)CX=(10);(4)DL=(10).4-7(1)VAR1、VAR2、VAR3的偏移地址是30H，3AH，40H；(2)DATA1的值是50H，CNT的值是16；(3)VAR2+2的内容为2。4-8（2）X为字变量，Y则可以字节方式访问X；（4）X为字变量，初值放在内存中的顺序为88H和62H，Y为字节变量，初值依次为62H和88H；（5）X和Y均为字变量，初值不同，因为X为16进制数，Y为10进制数。IO/MDT/RDENRDWR4-9（1）源操作数1000超过字节范围（3）CMP的两个操作数不能同时为存储器操作数（5）JNZ的转移位置不能用字变量给出4-11(1)DATA1DB86H,27H,23H,00H,24H,1AH(2)DATA2DW0B430H,1062H或者（1）DATA1LABELBYTEARRAYDW2786H,23H,1A24H(2)DATA2LABELWORDARRAYDB30H,0B4H,62H,10H4-12DATASEGMENTWORDTABLEDB100DUP(0)DATAENDSSTACKSEGMENTWORDSTACK‘STACK’DB1024DUP(0)STACKENDSCODESEGMENT‘CODE’ASSUMEDS:DATA,SS:STACK,CS:CODEMAINPROCFARSTART:PUSHDSMOVAX,0PUSHAXMOVAX,DATAMOVDS,AXMOVES,AXLEABX,TABLEMOVCX,100LOP:MOVBYTEPTR[BX],64HINCBXLOOPLOPRETMAINENDPCODEENDSENDSTART4-15TRANMACROX,Y,Z;X,Y,Z为源、目标数据块的首地址，Z为数据块的长度MOVCX,ZMOVSI,OFFSETXMOVDI,OFFSETYCLDREPMOVSBENDM4-16MOVAX,WORDPTRXADDAX,WORDPTRYMOVWORDPTRZ,AXMOVAX,WORDPTRX+2ADCAX,WORDPTRY+2MOVWORDPTRZ+2,AX4-17DATASEGMENTSTRGDB1000DUP(?)STR1EQUSTRG+7STG2EQUSTRG+27STRSEEQU50DATAENDSSTACKSEGMENTPARASTACK‘STACK’DB100DUP(?)STACKENDSCODESEGMENTASSUMECS:CODE,DS:DATA,ES:DATAMAIN:MOVAX,DATAMOVDS,AXMOVES,AXMOVCX,STRSEMOVSI,OFFSETSTG1MOVDI,OFFSETSTG2CLDPUSHSIADDSI,STRSE-1CMPSI,DIPOPSIJLOKSTDADDSI,STRSE-1ADDDI,STRSE-1OK:REPMOVSBMOVAX,4C00HINT21HCODEENDSENDMAIN4-18（1）DATASEGMENTDATAENDSCODESEGMENT…MOVAH,01H;从键盘输入一个字符，其ASC码值在AL中INT21HCMPAL,41HJZP0CMPAL,42HJZP1…CMPAL,4AHJZP9JMPEXITP1:…RETP2:…RET……P9:…RETEXIT:MOVAH,4CHINT21H….（2）DATASEGMENTBASEDWP0,P1,……,P9DATAENDSCODESEGMENT…MOVAH,01H;从键盘输入一个字符，其ASC码值在AL中INT21HCMPAL,'A';判别字符是否位于‘A’到‘J’之间JBEXITCMPAL,'J'JAEXITSUBAL,'A';在正确范围之内，根据表内地址分支MOVBL,ALMOVBH,0SHLBX,1JMPBASE[BX]P1:…RETP2:…RET……P9:…RETEXIT:MOVAH,4CHINT21H….4-19LEABX,xLEASI,yLEADI,sumADDBX,7ADDSI,7ADDDI,8;和可能要9个字节MOVCX,8CLCLOP:MOVAL,[BX]ADCAL,[SI]DAAMOV[DI],ALDECBXDECSIDECDIDECCXJNZLOPMOVAL,0ADCAL,0MOV[DI],AL4-20MOVSI,OFFSETFIRSTMOVCX,0;CX中存放A的个数LOOP:MOVAL,[SI]CMPAL,‘$’JZNEXTCMPAL,‘A’JNELPINCCXLP:INCSIJMPLOOPNEXT:……4-21DATASEGMENTDATA_WDW…………;若干个数COUTEQU($-DATA_W)/2COUT1DB0COUT2DB0COUT3DB0DATAENDSSTACKSEGMENTPARASTACK‘STACK’DB100DUP(0)STACKENDSCODESEGMENTASSAUMCS:CODE,DS:DATASTARTPROCFARPUSHDSMOVAX,0PUSHAXMOVAX,DATAMOVDS,AXMOVDX,0;正数、负数、0暂时分别存在BL、BH、DL中MOVBX,0LEASI,DATA_WMOVCX,COUTNEXT:MOVAX,[SI]CMPAX,0JGLP1JLLP2INCDLJMPOKLP1:INCBLJMPOKLP2:INCBHOK:ADDSI,2LOOPNEXTMOVCOUNT1，BLMOVCOUNT2，BHMOVCOUNT3，DLRETSTARTENDPCODEENDSENDSTART4-22DATASEGMENTARRAYDB…………;若干个数COUTEQU$-ARRAYMAXDB?MINDB?DATAENDSSTACKSEGMENTPARASTACK‘STACK’DB100DUP(0)STACKENDSCODESEGMENTASSAUMCS:CODE,DS:DATASTARTPROCFARPUSHDSMOVAX,0PUSHAXMOVAX,DATAMOVDS,AXLEABX,ARRAYMOVCX,COUTGOT:MOVAL,[BX]TESTAL,01HJZNEXTINCBXJMPGOTNEXT:MOVDH,ALMOVDL,AL；DH暂存最大偶数，DL暂存最小偶数，初始置首个偶数LEABX,ARRAYLOP:MOVAL,[BX]TESTAL,01HJNZNEXT2CMPAL,DLJANEXT1MOVDL,ALJMPNEXT2NEXT1:CMPAL,DHJBNEXT2MOVDH,ALNEXT2:INCBXLOOPLOPMOVMAX,DHMOVMIN,DLRETSTARTENDPCODEENDSENDSTART4-24LEABX,STRINGMOVCX,80NEXT:MOVAL,[BX]CMPAL,20HJZOKINCBXLOOPNEXTMOVCL,-1JMPFINOK:NEGCXADDCX,80FIN:…………4-25LEABX,STRINGMOVCH,0LOP:MOVAL,[BX]CMPAL,ODHJZEXITINCCHINCBXJMPLOPEXIT:…4-26（1）LEASI，STRING1LEADI，STRING2MOVCX，20CLDREPMOVSB（2）LEASI，STRING1LEADI，STRING2ADDSI，19ADDDI，19MOVCX，20STDREPMOVSB（3）MOVAL，20HLEADI,STRING1MOVCX,20CLDREPNZSCASBJZFOUNDMOVDL,0；未找到FOUND：DECDIMOVBX，DIMOVDL，01H；找到（4）LEASI，STRING1LEADI，STRING2MOVCX，20CLDREPCMPSBJNZNEQMOVBL，0;相同NEQ:MOVBL,01H；不相同4-28(1)DISPLAYPROCMOVCH,4MOVCL,4MOVBX,AX；（*）NEXT:ROLBX,CLMOVDL,BLANDDL,0FHADDDL,30HCMPDL,39HJBEPRINTADDDL,07HPRINT:MOVAH,2INT21HDECCHJNZNEXTRETDISPLAYENDP(2)与（1）基本相同，仅将（*）语句修改为MOVBX,WORDTEMP(3)将（*）句替换为下列语句(假设子程序中并未保护现场寄存器，主程序入栈的参数就是预显示的数据)MOVBP,SPMOVBX,[BP+2]4-29；模块1，文件名MAIN.ASMEXTRNDISPLAY:FAR；引用外部符号PUBLICMESG；定义外部符号DATA1SEGMENTMESGDB'ASSEMBLER$'DATA1ENDSCODE1SEGMENTASSUMECS:CODE1,DS:DATA1MAIN:MOVAX,DATA1MOVDS,AX；装入段基址PUSHDSCALLDISPLAYMVAH,4CHINT21HCODE1ENDSENDMAIN；模块2，文件名DISPLAY.ASMEXTRNMESGPUBLICDISPLAY；定义外部符号DATA2SEGMENTDB100UP(?)DATA2ENDSCODE2SEGMENTASSUMECS:CODE2,DS:DATA2DISPLAYPROCFARMOVAX,DATA2MOVDS,AX；装入段基址MOVDX,OFFSETMESGMOVAH,9；屏幕显示INT21HRETDISPLAYENDPCODE2ENDS4-30SUM1PROCNEARCMPCX，0JZEXIT1MOVAX，0；数组和在AX中AGAIN：ADDAL，[SI]ADCAH，0；和或许为字INCSILOOPAGAINEXIT1：RETSUM1ENDP4-31STACKSEGMENTPARASTACK‘STACK’DB100DUP(0)STACKENDSCODESEGMENTASSAUMCS:CODESTARTPROCFARPUSHDSMOVAX,0PUSHAXMOVAX,DATAMOVDS,AXMOVCX,4MOVDX,0.LOP1:MOVAH,1INT21HCMPAL,46HJAEXIT;字符ASCII码不在0~9，A~F之间CMPAL,40HJALOP2CMPAL,39HJAEXIT;字符ASCII码不在0~9，A~F之间CMPAL,30HJBEXIT;字符ASCII码不在0~9，A~F之间SUBAL,30HJMPNEXTLOP2:SUBAL,37HNEXT:MOVAH,0PUSHCXMOVCL,4ROLDX,CLPOPCXADDDX,AXLOOPLOP1EXIT:RETSTARTENDPCODEENDSENDSTART5-41KX8:末地址=1000H+3FFH