exp1102.asm

汇编语言 参考书 包含作业与答案 从入门到精通 通俗易懂

STACK   SEGMENT PARA STACK
        DW      100h DUP(?)
STACK   ENDS

DATA    SEGMENT PARA
F_NAME          DB      'C:TEST.DAT',00H
FILE_H          DW      ?
BUFF            DB      1024*10 DUP(?)
LEN             DW      ?
DATA    ENDS

CODE    SEGMENT PARA
        ASSUME  CS:CODE,DS:DATA,SS:STACK
MAIN    PROC    FAR
        MOV     AX,DATA
        MOV     DS,AX

        MOV     DX,OFFSET F_NAME
        MOV     CX,0
        MOV     AH,3Dh
        MOV     AL,02h
        INT     21H
        JC      RETURN
        MOV     FILE_H,AX

        MOV     BX,AX

        MOV     AH,3Fh
        MOV     CX,1024*10
        LEA     DX,BUFF
        INT     21H
        JC      RETURN
        MOV     LEN,AX

        LEA     SI,BUFF
        MOV     DI,SI
        PUSH    DS
        POP     ES
        CLD
        MOV     CX,LEN
LP1:    LODSB
        CMP     AL,'a'
        JB      CON1
        CMP     AL,'z'
        JA      CON1
        SUB     AL,20H
CON1:   STOSB
        LOOP    LP1

        XOR     CX,CX
        XOR     DX,DX
        MOV     BX,FILE_H
        MOV     AX,4200h
        INT     21h

        LEA     DX,BUFF
        MOV     CX,LEN
        MOV     BX,FILE_H
        MOV     AH,40h
        INT     21h

        MOV     AH,3Eh
        MOV     BX,FILE_h
        INT     21h

RETURN: MOV     AX,4C00h
        INT     21h

MAIN    ENDP
CODE    ENDS
        END     MAIN