;::::::::::::::::::::::::::::::::::::::::::::::::::::

;

; file: toupper.asm

;

; This program converts lowercase characters

; to corresponding uppercase.

;

; Input: A string entered on the keyboard, terminated

;        with the carriage return character.

;

; Output: Prints the string in uppercase.

;

; Author: Caiden Robinson

; Date: 4/18/11

;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;



%include "asm_io.inc"



LF  equ 0Ah



segment .data

;

; initialized data is put in the data segment here

;



name_prompt    DB  'Please type your name: ',0

rep_prompt DB 'Do you want to quit (Y/N) :',0

out_msg        DB  'Your name in capitals is: ',0



;Ans_Y DB 'Y'

;Ans_N DB 'N'



segment .bss

;

; uninitialized data is put in the bss segment

;



in_name    resb  30

in_ans resb 1



segment .text

        global  asm_main

asm_main:

        enter   0,0            ; setup routine

        pusha



    begin:



        mov  eax, name_prompt  ; print prompt

    call print_string

    mov  ebx, in_name

rd_loop:

        call read_char         ; read in the string

    mov  [ebx], al

        inc  ebx

    cmp  al, LF

        jne  rd_loop



    dec  ebx               ; put in null terminator

    mov  byte [ebx], 0

        call print_nl          ; print output msg

        mov  eax, out_msg

    call print_string



        mov  ebx, in_name      ; EBX := address of in_name

process_char:

        mov     AL,[EBX]       ; move the char to AL

        cmp     AL,0           ; if it is the NULL character

        je      done           ;  conversion done

        cmp     AL,'a'         ; if (char < 'a')

        jl      not_lower_case ; not a lowercase letter

        cmp     AL,'z'         ; if (char > 'z')

        jg      not_lower_case ; not a lowercase letter

lower_case:

        add     AL,'A'-'a'     ; convert to uppercase

not_lower_case:

    call    print_char

        inc     EBX            ; BX points to next char.

        jmp     process_char   ; go back to process next char.



done:

        call print_nl

        call print_nl



;;This is a loop that asks the user if

;;they would like to repeat the program



Rep_rd_loop:

    mov eax, rep_prompt

    call print_string

    mov ebx, in_ans



    call read_char

    mov [ebx], al

    call read_char

    call print_nl



    mov al, [ebx]

    cmp AL, 'y'

    je done2

    cmp AL, 'Y'

    je done2

    cmp AL, 'n'

    je begin

    cmp AL, 'N'

    je begin

    jmp Rep_rd_loop



done2:



        popa

;;;;;;;;;;;;;;;



;;;;;;;;;;;;;;;

        mov     eax, 0         ; return back to C

        leave

        ret