ORG 100h
 
    MOV si,sp ; Save stack pointer!
 
input_loop:
    XOR ax,ax
    INT 16h ; Use int16 to get a keystroke
 
    CMP al,' ' ; is it a space char?
     JE input_loop ; if space, get another char
 
    PUSH ax ; Save current char on stack top!
    CMP al,13 ; Terminating CR?
     JNE input_loop
 
    POP ax ; Get rid of last pushed char (terminating CR)
     JMP test_stack
 
disp_loop:
    POP dx ; DL will get the pushed char
    MOV ah,2
    INT 21h
 
test_stack:
    CMP si,sp ; Is the stack back where we started?
     JNE disp_loop
 
done: ; So,exit
    MOV ax,0x4C00
    INT 0x21