p1.asm

用汇编语言编写的在MASM上实现大小写转换,排序,比较大小的源程序和可执行文件

EXTRN   START:FAR
PUBLIC  SUB1

HUANHANG  MACRO
          MOV DL,0DH
          MOV AH,2
          INT 21H
          MOV DL,0AH
          MOV AH,2
          INT 21H
ENDM

DATA1 SEGMENT
MEGP1   DB '1.TURN SMALL LETTERS TO CAPITAL LETTERS(PLEASE ENTER STRINGS):$'   
BUFP1   DB 100
        DB ?
STRP1   DB 100 DUP(?)
DATA1 ENDS

STACK SEGMENT PARA STACK 'STACK'
      DB 100 DUP(0)
STACK ENDS

CODE1  SEGMENT
       ASSUME CS:CODE1,DS:DATA1
SUB1: PUSH DS
      PUSH AX
      PUSH DX
      MOV AX,DATA1
      MOV DS,AX
     
BB:   MOV DX,OFFSET MEGP1
      MOV AH,9
      INT 21H
     
      HUANHANG      
            
      MOV DX,OFFSET BUFP1
      MOV AH,10
      INT 21H

      HUANHANG           

      MOV SI,OFFSET STRP1
      MOV CL,[SI-1]
      MOV CH,0
      CMP CL,0
      JE  CC      

NEXTP1: MOV AL,[SI]   
      MOV BL,AL
      SUB BL,61H
      JL  AA      
      CMP BL,7AH
      JG  AA
      
      SUB AL,20H

AA:   MOV DL,AL
      MOV AH,2
      INT 21H      
      INC SI
      LOOP NEXTP1          

CC:   HUANHANG
      MOV AH,0
      INT 16H
      CMP AL,1BH
      JE  EXITP1
      JMP BB

EXITP1:HUANHANG
       HUANHANG
       POP DX
       POP AX
       POP DS
       JMP START
CODE1  ENDS
       END