str

        model tiny
        .code
        org 80h
len db ?
par db ?
        org 100h
e:
        jmp start
buffer db 255(?)

start:
        mov si, offset par
        xor cx, cx
        xor dx, dx
        mov cl, len
        mov di, offset buffer
l:
        lodsb
        cmp ax, ' '
        je l1
        inc dx
        stosb
l1:
        loop l

        mov ax, '$'
        stosb

        mov cx, dx
        mov ah, 09h
        mov dx, offset buffer
        int 21h
        ret
end e