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- assume cs:code,DS:data,SS:stack
- data segment
- DB "Beginner's All-purpose Symbolic Instruction Code.",0
- data ends
- stack segment
- DW 8 dup(0)
- stack ends
- code segment
- start:
- MOV AX,data
- MOV DS,AX
- MOV AX,stack
- MOV SS,AX
- MOV sp,16
- MOV SI,0
- CALL letterc
- mov ax,4c00h
- int 21h
- ;将一串结尾为0的字符中的小写转换成大写
- letterc:
- PUSH AX
- PUSH SI
-
- S:MOV AL,[si]
-
- CMP AL,0 ;等于0跳出循环
- JE jies
-
- CMP AL,61h ;是不是小于a
- JB OK
-
- CMP AL,7Ah ;是不是大于z
- JA OK
- AND al,1011111B ;将小写转换大写
- MOV [si],AL
-
- OK:INC SI
- JMP S
-
- jies:
- POP SI
- POP AX
- RET
-
- code ends
- end start
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