我一直试图划分单词大小的变量，结果商总是1，余数总是除数除数。什么可能出错？提前谢谢。
section .data
section .bss
num1a resw 1
num1b resw 1
num2a resw 1
num2b resw 1
section .text
global _start
_start:
;get inputs
mov eax, 3
mov ebx, 0
mov ecx, num1a
mov edx, 1
int 80h
mov eax, 3
mov ebx, 0
mov ecx, num1b
mov edx, 2
int 80h
mov eax, 3
mov ebx, 0
mov ecx, num2a
mov edx, 1
int 80h
mov eax, 3
mov ebx, 0
mov ecx, num2b
mov edx, 2
int 80h
;convert
sub word[num1a], 30h
sub word[num1b], 30h
sub word[num2a], 30h
sub word[num2b], 30h
mov ax, 0
mov bx, 0
mov ax, [num1a]
mov bx, 10
mul bx
add ax, [num1b]
mov word[num1a], ax
mov ax, 0
mov bx, 0
mov ax, [num2a]
mov bx, 10
mul bx
add ax, [num2b]
mov word[num2a], ax
;divide
mov ax, 0
mov dx, 0
mov ax, [num1a]
div word[num2a]
mov word[num1a], ax
mov word[num2a], dx
mov ax, 0
mov dx, 0
mov ax, [num1a]
mov bx, 10
div bx
mov word[num1a], ax
mov word[num2a], dx
;convert
add word[num1a], 30h
add word[num2a], 30h
;print
mov eax, 4
mov ebx, 1
mov ecx, num1a
mov edx, 1
int 80h
mov eax, 4
mov ebx, 1
mov ecx, num2a
mov edx, 1
int 80h
exit:
mov eax, 1
mov ebx, 0
int 80h