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微机原理 汇编语言指令 求大神给个详细解释 微机原理与汇编语言跳转指令

2021-04-10知识4

微机原理与汇编语言 题目:用跳转语句实现从键盘接收一个字符,如果是小写字母则输出“L”,大写字母 code segmentassume cs:codeorg 100hstart:jmp beginmsg db 13,10,13,10,'PLEASE INPUT:$'char1 db?m dw 0big db 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'bign equ$-bigloww db 'abcdefghijklmnopqrstuvwxyz'lown equ$-lowwdig db '0123456789'dign equ$-digbegin:push cspop dspush cspop ese79fa5e98193e58685e5aeb9313333613263330:mov word ptr m,0lea dx,msgmov ah,9int 21hmov ah,1int 21hmov char1,alcmp al,13je@exitmov cx,bignmov al,char1cldlea di,bigrepne scasbcmp cx,0je@1mov ah,2mov dl,'U'int 21hinc word ptr m1:mov cx,lownmov al,char1cldlea di,lowwrepne scasbcmp cx,0je@2mov ah,2mov dl,'L'int 21hinc word ptr m2:mov cx,dignmov al,char1cldlea di,digrepne scasbcmp cx,0je@3mov ah,2mov dl,'N'int 21hinc word ptr m3:cmp word ptr m,0jne@0mov dl,'*'mov ah,2int 21hjmp@0exit:mov ah,4chint 21hcode endsend start

微机原理汇编语言 00hcall far ptr把CS,IP压栈处理,然后实现跳转,相当于段间转移,远转移(sp)=(sp)– 2((ss)*16+sp)=(cs)(sp)=(sp)– 2((ss)*16+sp)=(ip)

微机原理汇编语言IDIV指令 IDIV:有符号数除法指袭令(SignedInteger Divide Instruction);指令的百格式:IDIV Reg/Mem;受影响的标志位:AF、CF、OF、PF、SF和ZF;指令的功能是用显式操作数去除隐含度操作数(都作为问有符号数),所得商和答余数的对应关系见下图;

#微机原理与汇编语言跳转指令

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