intercalate elements of two strings assembly 8086

Question

I have a little problem with my program. I have to intercalate the elements of two strings,so if i have

S1: 1, 3, 5, 7
S2: 2, 6, 9, 4

it will result D: 1, 2, 3, 6, 5, 9, 7, 4.

This is what i did so far, and i have no idea how to fix it, any help please?

assume cs:code, ds:data

data segment
s1 db '1357'
s2 db '2694'
l1 EQU ($-s1)
l2 EQU ($-s2)
d db (l1+l2) dup (?)
data ends

code segment
start:
mov ax,data
mov ds,ax

mov si,offset s1
mov cx,l1
mov bx, 0
frst:
    mov ax,[si]
    mov [di]+[bx],ax
    inc si
    add bx,2
loop frst
mov si, offset s2
mov cx,l2
mov bx,1

scnd:
    mov ax,[si]
    mov [di]+[bx],ax
    inc si
    add bx,2
loop scnd

mov ax,4c00h
int 21h
code ends
end start

Answer 1

There are several mistakes in the code, firstly

s1 db '1357'
s2 db '2694'
l1 EQU ($-s1)
l2 EQU ($-s2)

gets the length of s1 wrong, it should be

s1 db '1357'
l1 EQU ($-s1)
s2 db '2694'
l2 EQU ($-s2)

Secondly, di is used but not initialised, insert

mov di, offset d

before the first loop. Next, the data arrays are byte values defined by db , but you are loading and storing ax register. This should be the al register, as

mov al,[si]
mov [di]+[bx],al