Addition of an Array of N Hexadecimal Nos. in NASM[x86/64 architecture]

Problem Statement: Write X86/64 Assembly language program (ALP) to add array of N hexadecimal numbers stored in the memory. Accept input from the user.

%macro print 2   ;macro to print
mov rax,1
mov rdi,1
mov rsi,%1
mov rdx,%2
syscall
%endmacro

%macro accept 2   ;macro to accept  
mov rax,0
mov rdi,0
mov rsi,%1
mov rdx,%2
syscall
%endmacro

SECTION .data
msg1: db "Enter quantity of numbers to add: "
len1: equ $-msg1
msg2: db "Enter the hexadecimal numbers: ",0xA
len2: equ $-msg2
msg3: db "The sum is: "
len3: equ $-msg3
msg4: db " ",0xA
len4:equ $-msg4

SECTION .bss
input: resb 100
result: resb 4
count1: resb 2
count2: resb 2
count: resb 2
num: resb 3

SECTION .text
global main
main:

print msg1,len1       ;calling macro to print
accept num,3          ;calling macro to accept
call convert         ;calling procedure to convert ASCII to hex 
mov byte[count1],bl
mov byte[count2],bl

print msg2,len2
mov r9,input
array:         ;accept numbers and store it in the array     
   accept num,3
   call convert
   mov [r9],bl
   inc r9
   dec byte[count1]
   jnz array

mov r9,input
mov al,00
mov ah,00
call add   ;calling procedure to add the numbers
print msg3,len3
print result,4
print msg4,len4

mov rax,60
mov rdi,1
syscall

convert:   ;procedure to convert ASCII to hex
mov ch,02
mov bl,00
mov r10,0
loop:
    mov al,[num+r10]
    cmp al,61H   ;comparing for lower case letters
    jb next
    sub al,57H
    jmp next2
next:
    cmp al,41h   ;comparing for upper case letters
    jb next1
    sub al,37H
    jmp next2
next1:
     sub al,30H   ;comparing for numbers
next2:
     shl bl,04H
     add bl,al
     inc r10
     dec ch
     jnz loop
ret

add:   ;procedure to add and convert hex to ASCII
mov bl,[r9]
add ax,bx   ;to add numbers in the array
inc r9
dec byte[count2]
jnz add
mov r10,result
mov byte[count],4
l1:               ;to convert to ASCII
    rol ax,04H
    mov dl,al
    and dl,0FH
    cmp dl,09H
    jbe l2  
    add dl,07H
    l2:
    add dl,30H  
    mov[r10],dl
    inc r10
    dec byte[count2]
    jnz l1
ret

Output

amodi@ubuntu:~/MIL/Assign1$ nasm -f elf64 -l add64.lst add64.asm
amodi@ubuntu:~/MIL/Assign1$ ld -o add64 add64.o
ld: warning: cannot find entry symbol _start; defaulting to 00000000004000b0
amodi@ubuntu:~/MIL/Assign1$ ./add64
Enter quantity of numbers to add: 06
Enter the hexadecimal numbers:
11
22
33
AA
CC
DF
The sum is: 02BB