.data
;_______________
 arr db "123456789hytiwenf56",0
;_______________
.code
start:
 mov ecx,0
aga:
 mov al, byte ptr [arr+ecx]
 cmp al,'0'
 jl qu
 cmp al,'9'
 jg qu
 mov byte ptr [arr+ecx],'*'
qu:
 cmp al,0
 inc ecx
 jz aga
ret
end start