Assembly-convert lowercase letters to uppercase letters

Zookeeper I. Internship questions:Convert lowercase letters to uppercase letters

II. Purpose:

 1. Master branch program design methods

2. Understand the representation of lower-case letters and upper-case letters on the computer and display them.

III. Code:

 

Data segment A db 'A'; B db 'Z'; C db 00 h; bb db 0ah, 0dh, '$' string db 0ah, 0dh, 'The input num is not a case letter ',' $ '; data endscode segment assume DS: data, CS: code start: mov ax, data; mov ds, ax; mov ah, 01 h; int 21 h; cmp al, A; jl next1; cmp al, B; jg next1; mov C, al; mov dl, bb; mov ah, 02 h; int 21 h; mov al, C; sub al, 20 h; mov dl, al; mov ah, 02 h; int 21 h; jmp next2; next1: lea dx, string; mov ah, 09 h; int 21 h; next2: mov ah, 4ch; int 21 h; code endsend start

IV. Running result:

Zookeeper

Assembly-convert lowercase letters to uppercase letters