汇编语言代码.doc

汇编语言编写从键盘输入一段字符串然后逆序输出DATA SEGMENTDB 512 DUP($) ;定义可输入的字符个数BUF DB $CRLF DB 0DH,0AH,24H ;回车换行符DATA ENDSCODE SEGMENTASSUME CS:CODE,DS:DATASTART: MOV AX,DATA MOV DS,AXMOV BX,OFFSET BUF ;指针指向待显示字符串尾部AGAIN:MOV AH,01 ;输入字符INT 21HCMP AL,0DH ;是回车吗JE DISP ;是,转显示DEC BX ;指针减1MOV BX,AL ;存入输入的字符JMP AGAIN ;继续输入DISP:MOV AH,09 ;显示MOV DX,OFFSET CRLF ;回车换行INT 21HMOV DX,BX ;定位待显示字符串首地址MOV AH,09 INT 21H ;显示MOV AH,4CH ;DOS返回INT 21HCODE ENDSEND START; 本程序通过编译，运行正确Code Segment Assume CS:Code,DS:Code; ; 功能：显示指定地址（Str_Addr）的字符串; 入口：; Str_Addr字符串地址（要求在数据段）; 用法: Output Str_Addr; 用法举例：Output PromptStrOutput MACRO Str_Addr lea dx,Str_Addr mov ah,9 int 21h EndM; ; 功能：输出一个字符 ; 入口：dl=要显示的字符 Enter_Chr proc Near push ax mov ah,02h int 21h pop ax ret Enter_Chr endp ; ; 功能：输出回车换行Enter_CTLF proc Near push ax push dx mov ah,02h mov dl,0dh int 21h mov dl,0ah int 21h pop dx pop ax retEnter_CTLF endp ; Prompt_Str db Please input a string: $ ;输入字符串提示信息Start: push cs pop ds push cs pop es ;使数据段、附加段与代码段同段 Output Prompt_Str ;提示输入字符串 lea dx,Buffer mov ah,0ah ;从键盘接受一串字符 int 21h CALL Enter_CTLF ;输出一个回车、换行 CALL Enter_CTLF ;输出一个回车、换行 cld lea si,Buffer1 ;实际输入的字符个数地址 mov cl,si ;读入实际输入的字符个数 test cl,0ffh jz Exit_Proc ;直接回车，没有输入任何字符，结束程序，返回操作系统 xor ch,ch ;cx=实际输入的字符个数 add si,cx ;字符串尾部地址 std ;置方向标志，使变址寄存器自动减量Disp_String:lodsb mov dl,al call Enter_Chr ;显示一个字符 loop Disp_StringExit_Proc: mov ah,4ch ;结束程序 int 21hBuffer db 100,?Code ENDS END Start ;编译到此结束从键盘输入一字符串（不超过255个字符）以相反顺序输出data segmenta db ? dup(?)data endseseg segmentb db ? dup(?)eseg endscode segmentassume cs:codestart:mov ah,0ahint 21hmov bl,allea si,alea di,badd di,n-1mov cx,nmove:cldlodsbstdstosbloop movemov ah,4chint 21hcode endsend start解答：data segment;a db ? dup(?)a db 255,0,255 dup(?)data endseseg segment;b db ? dup(?)b db 255 dup(?)eseg endscode segment;assume cs:codeassume cs:code,ds:data,es:esegstart:mov ax,data ;新增mov ds,ax ;mov ax,eseg ;mov es,ax ;mov dx,offset a ;学习0AH号DOS功能调用mov ah,0ahint 21h;mov bl,almov ch,0 ;mov cl,a+1 ;lea si,alea si,a+2lea di,b;add di,n-1add di,cxdec di;mov cx,nmove:cldlodsbstdstosbloop movemov ah,4chint 21hcode endsend start;输入字符串去空格后反向输出的程序.modelsmall.386DATASEGMENTbufdb100,0,100DUP(0)msg1dbPleaseinputastring:,0DH,0Ah,$crlfdb0Dh,0Ah,$lengdb0DATAENDSSTACKSEGMENTDB64DUP(?)STACKENDSCODESEGMENTassumecs:CODE,ds:DATA,es:DATA,ss:STACKSTART:movax,DATAmovds,axmoves,axleadx,msg1;输出提示文字movah,09hint21hleadx,bufmovah,0ah;接受字符串int21h;movdx,offsetcrlfmovah,09h;输出字符串中断int21hcallcountcallnospace;把这行去掉之后是可以实现反向输出的，当然不能去空格leadx,bufmovbl,leng;新字符串长度送到blmovbh,00hcmpbx,0000hjnzL1jzEXITL1:movdl,buf+1bx;把最后一位送到dlmovah,02h;输出一个字符中断int21hdecbx;倒着输出字符jnzl1EXIT:movAH,4CHint21Hcount:xordx,dxxorcx,cxleadi,bufpushdimoval,0lop:cmpal,dijedoneincdlincdilooplopdone:movleng,dl;把数组长度存至lengpopdiretnospace:pushsipushdipushaxpushbxpushcxleasi,bufaddsi,2;读指针simovdi,si;写指针dixorch,chmovcl,si-1;字符数组长度cldxorbl,bl;新的字符长度L2:lodsb;读取字符cmpal,jeL3;如果是空格，跳过保存操作stosb;保存字符incbl;记录长度L3:loopL2movleng,blpopcxpopbxpopaxpopdipopsiretCODEENDSENDSTART字符串逆序输出data segment string db 100,?,100 dup(0)data endscode segment assume cs:code,ds:datastart:mov ax,data mov ds,ax lea dx,string mov ah,0ah int 21h lea bx,string+1 mov cl,bx mov ch,0 add bx,cx next:mov dl,bx mov ah,2 int 21h dec bx loop next mov ah,4ch int 21hcode ends end start提示一下，小写跟大写字母的ASCII码值就差32，例如a=97=61h,A=41h=65,所以只要将小写字母-20h即可,先简单写个，没运行，参考一下吧MOV DX,DATAMOV DS,DXLEA DX,BUFMOV AH,0AHINT 21HMOV DI,OFFSET BUFMOV CL,DI+1XOR CH,CHADD DI,2NEXT:CMP DI,a JB NEXT1 CMP DI,z JA NEXT1 SUBB DI,20H INC DINEXT1:LOOP NEXT MOV DI,OFFSET BUF MOV CL,DI+1 XOR CH,CH ADD DI,2 ADD DI,CX-1DISP:MOV DL,DI MOV AH,2 INT 21H INC DI LOOP DISP利用10号功能调用从键盘输入长度为8的字符串，回车键结束，然后将其逆序输出DATA SEGMENTBUF DB 8 DB ? DB 8 DUP(0)DATA ENDSCODE SEGMENT ASSUME