Converting decimal to binary in assembly x86

Question

I'm trying to write decimal to binary converter and for some numbers it works and for others it doesn't. 0 - 8 numbers works fine, but when I input 9 it displays 101.

SYSEXIT = 1
SYSREAD = 3
SYSWRITE = 4
STDOUT = 1
STDIN = 0
 
.bss                                   
.equ bufsize, 32               
.lcomm buf, bufsize             #buf - saved user input
                       
.equ buf2size, 32              
.lcomm buf2, buf2size           #binary in wrong order
 
.equ buf3size, 32              
.lcomm buf3, buf2size           #binary correct order
 
.data
 
msg_podaj:
.ascii "Wprowadz liczbe:\n"
msg_dlpodaj = .- msg_podaj
 
msg_test:
.ascii "TEST\n"
msg_dltest = .- msg_test
 
.text
.global _start
 
_start:
 
 
mov $SYSWRITE, %eax                             
mov $STDOUT, %ebx
mov $msg_podaj, %ecx
mov $msg_dlpodaj, %edx
int $0x80
 
mov $SYSREAD, %eax                              
mov $STDIN, %ebx
mov $buf, %ecx
mov $bufsize, %edx
int $0x80
 
xor %eax, %eax
xor %ecx, %ecx
 
mov $0, %edi                            
movb buf(,%edi,), %al                   
sub $48, %eax                           
 
read:
incl %edi                                            
movb buf(,%edi,), %cl                   
sub $48, %ecx
 

cmp $0, %cl                            
jl tu                                   
cmp $9, %cl                             
jg tu                              
 
imul $10, %eax                          
add %ecx, %eax                         
 
jmp read

tu:
 
mov $0, %edi                            
mov $0, %edx
mov $2, %ebx
 
cmp $0, %eax
je wstaw
 
movb $'1', buf3(,%edi,)
jmp loop
 
wstaw:
movb $'0', buf3(,%edi,)
 
loop:
cmp $1, %eax
jle changeorder
 
incl %edi
DIV %ebx
mov %edx, buf2(,%edi,)
add $'0', buf2(,%edi,)
 
jmp loop
 
changeorder:
mov $1, %esi
 
loop2:
cmp $0, %edi
je display
 
movb buf2(,%edi,), %ah
movb %ah, buf3(,%esi,)
incl %esi
decl %edi
jmp loop2
 
display:
mov $SYSWRITE, %eax
mov $STDOUT, %ebx
mov $buf3, %ecx
mov $buf3size, %edx
int $0x80
 
exit:                                         
mov $SYSEXIT, %eax
int $0x80