[TASM]как работает этот код для сортировки знаков методом подсчета - Assembler

dosseg
.model small
.stack 100h
org 100h
.data
maxlen  db 254
len     db 0
array   db 255 dup(0)   
count   db 256 dup(0)   
survey  dw ?
txt     db  10, 13, "Eta programma sortiruet vse metodom podscheta: ",0
UNGR = 041h
OBGR = 05Ah
ESCt = 1Bh

jumps
include macros.mac
.code
	start:

mov ax,@DATA
mov ds,ax
mov es,ax                

	prog:
writes txt              
nl
mov ah,0ah              
mov dx,offset array-2    
int 21h

xor si,si
xor ax,ax
mov al,[len] 		
	
	sort:
xor bx,bx
mov bl,byte ptr [array+si]   
inc   [count+bx]             

inc   si                  
cmp   si,ax		   
jne   sort

xor si,si
mov di,offset array	  

how:

xor cx,cx
mov cl, [count+si]         

test cx,cx
jz increm

mov   ax,si
rep   stosb

	increm:
inc   si
cmp   si, 256
jne how
mov byte ptr es:[di],'$'

;-----Vyvod

mov ah,9
mov dx,offset array
int 21h
mov ah,7
int 21h
nl
cmp al,1
jnz again
ret

again:
print "again(y/n): ?"
nl
reads survey
cmp survey, 59h 
je start
cmp survey, 4eh
je quit
cmp survey, 79h
je start
cmp survey, 6eh
je quit
jne again

	quit:

mov ah,4ch
int 21h
end start