Question

Having a bit of difficulty getting my input to print once a white space character is inputted. So far, i have it to display the uppercase/lowercase of the input but once i enter a string it doesnt read whats after the white space character. any suggestions?

EDIT: intel x86 processor and im using EMU8086

org 100h

include 'emu8086.inc'
printn "Enter string to convert" 
mov dx,20
call get_string

printn
mov bx,di
mov ah,0eh

mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower1
cmp al, 61h
cmp al, 7ah
jle ToUpper1

ToLower1:
add al, 20h
int 10h
jmp stop1
ToUpper1:
sub al, 20h
int 10h
stop1:

inc bx
mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower2
cmp al, 61h

cmp al, 7ah
jle ToUpper2

ToLower2:
add al, 20h
int 10h
jmp stop2
ToUpper2:
sub al, 20h
int 10h
stop2:

inc bx
mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower3
cmp al, 61h

cmp al, 7ah
jle ToUpper3

ToLower3:
add al, 20h
int 10h
jmp stop3
ToUpper3:
sub al, 20h
int 10h
stop3:

inc bx
mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower4
cmp al, 61h

cmp al, 7ah
jle ToUpper4

ToLower4:
add al, 20h
int 10h
jmp stop4
ToUpper4:
sub al, 20h
int 10h
stop4:

inc bx
mov al,[ds+bx]
cmp al, 41h

cmp al, 5Ah
jle ToLower5
cmp al, 61h
cmp al, 7ah
jle ToUpper5

ToLower5:
add al, 20h
int 10h
jmp stop5
ToUpper5:
sub al, 20h
int 10h
stop5:



printn
hlt
define_get_string
define_print_string
end

Answer 1

@Oded, those registers are x86 and emu8086 would imply an emulator for the 8086 CPU.

@OP:
Well your adding 32 to a character code to make it lower right? The ASCII code for space is 32 and the ASCII code for the @ symbol is 64 right? That should tell you your compares are wrong somewhere.

cmp al, 41h ;A
; WHAT ARE YOU MISSING HERE?
cmp al, 5Ah ;Z
jle ToLower1

cmp al, 61h ;a
; WHAT ARE YOU MISSING HERE?
cmp al, 7ah ;z
jle ToUpper1

Do you see the error? This is basically telling the CPU if the current character is equal to or less than Z to make lower. Also, if the character is equal to or less than z to make upper.

So what you have is:

You need a conditional jump after cmp al, 41H and a conditional jump after cmp al, 61H

But that still won’t work, this should work:

cmp     al, 41H
jb      CheckForLower
cmp     al, 5AH
ja     CheckForLower
; convert to lowercase here
; Process next char

cmp     al, 61H
jb      NotValid
cmp     al, 7AH
ja      NotValid
; convert to uppercase here
; Process next char

* Edit *
We can condense all that code into 1 loop:

org 100h

include 'emu8086.inc'
printn "Enter string to convert" 
    mov     dx,20
    call    get_string

printn
    mov     bx, di
    mov     ah,0eh 

    jmp     Start  

NextChar:
    inc     bx 

Start:
    mov     al, [ds+bx]   
    test    al, al
    jz      stop5      

    cmp     al, 20H    
    je      PrintChar   

    cmp     al, 41H    
    jb      CheckLower  
    cmp     al, 5AH
    ja      CheckLower
    add     al, 20H   
    int     10H
    jmp     NextChar

CheckLower:
    cmp     al, 61H
    jb      NextChar
    cmp     al, 7AH
    ja      NextChar
    sub     al, 20H           

PrintChar:
    int     10H
    jmp     NextChar 

stop5:
    printn  
    hlt
    define_get_string
    define_print_string
end