Assembly language-Alphabetic character conversion

1. Title: Uppercase and lowercase alphabetic characters interchange

2. Requirements: Enter a character from the keyboard, if the character is a carriage return, exit the program directly, if it is a lowercase letter, it is converted to uppercase and displayed, if it is uppercase, is converted to lowercase letters and display, if it is non-alphabetic characters, display a prompt message, and wait for the user to reenter characters.

3. Tip: First determine whether it is a carriage return, if not, whether it is uppercase or lowercase letters, if the conversion and output, otherwise display re-enter. The difference between uppercase ASCII and lowercase ASCII is 20H, which can be converted according to this.

 1; Example assembly Language Program--2; Author:karllen 3; Date:revised 5/2014 4 5.386 6. MODEL FLAT 7 8 exitprocess PROTO NEAR32 stdcall, Dwexitcode:dword 9 INCLUDE io.h; Header file for input/output11-cr EQU 0DH; Carriage return character13 Lf EQU 0ah; Line Feed14 15. STACK 4096; Reserve 4096-byte stack16 17. DATA18 Promot byte "Enter a char of letter", cr,lf,019 warning byte "The char isn ' t a letter,enter AG       Ain ", 020 answerltou byte" The char is a lowercase,it's uppercase is "a byte cr,lf,023 Answerutol byte "The char is a uppercase,it's lowercase is" a byte cr,lf,025 char B Yte 1 DUP (?) 26.         CODE27 _start:28 output promot29 input char,130 dogo:31 mov bl,char32 input char,133           CMP char,0dh34 JE dowhcmp; CR deal the CR35 jmp doGo36 dowhcmp:37    Bl,41h39 JL Inputagain; the char < a,end and input again40 cmp bl, 5ah41 Jle Enduppertol; the char <= z,so to judge it's or not lowercase42; th              e Char is a uppercase43 cmplower:44 CMP bl,61h; the char < a,end and input Again45              JL INPUTAGAIN46 CMP Bl,7ah; the char > Z.end and input agian47 JG inputAgain48               JMP Endlowertou; The char is a lowercase49 inputagain:51 output warning 52              Input char,153 mov bl,char54 jmp doGo55 enduppertol:56 mov al,bl57 add al,32; here is the decimal plus minus the Mov char,al59 output Answeru              toL60 output char61 jmp endMain62 endlowertou:63 mov al,bl64      Sub al,3265        mov char,al66 output answerLtoU67 output char68 endmain:69 ExitProcess INVOKE, 0; Exit with return code 071 _start; Make entry point public73 the END; End of source code

Assembly language-Alphabetic character conversion