64 bit:-Addition of 10 User Input Hexadecimal Number using Assembly Language x64

Q: Accept 10, 64 bit hexadecimal numbers from the user and print their sum.

Steps involved:-

1. Accept the numbers in Ascii format
2. Convert the numbers to hexadecimal form.
3. Add the numbers to get the sum.
4. Convert the sum to Ascii format.
5. Display the result.

Code:-

• OS:- Linux x64
• Assembler:- Nasm
• Debugger:- GDB

;macros begin
%macro read 2
mov rax,00
mov rdi,01
mov rsi,%1
mov rdx,%2
syscall
%endmacro

%macro write 2
mov rax,01
mov rdi,00
mov rsi,%1
mov rdx,%2
syscall
%endmacro
;macros end

section .data

msg1 db "Enter number",10
len1 equ $-msg1
msg2 db "The answer of the addition is",10
len2 equ $-msg2
section .bss
innum resb 170
count resb 1
count2 resb 1
asciians resb 16

section .text
global _start
_start: 

;reading of numbers
mov r8,innum
mov byte[count],10
l1:
write msg1,len1
read r8,17
add r8,17
dec byte[count]
jnz l1
;reading of numbers is now complete

mov r15,0
mov r14,0
mov byte[count],10
mov r8,innum


l2:
call a2h
add r14,r9
adc r15,0h
add r8,1
dec byte[count]
jnz l2
;addition complete

mov rax,r15
call h2a
write msg2,len2
write asciians,16
mov rax,r14
call h2a
write asciians,16
;exit system call
mov rax,60
mov rdi,0
syscall


a2h: ;source at r8, answer at r9
mov byte[count2],16
mov r9,0
mov rax,0
loop:
rol r9,4
mov rax,0
mov al,[r8]
sub al,30h
cmp al,9h
jbe nocorrection
sub al,7h
nocorrection:
add r9,rax
inc r8
dec byte[count2]
jnz loop
ret

h2a: ;source at rax, answer at asciians
mov rdi,asciians
mov byte[count2],10
loop2:
rol rax,04
mov bl,al
and bl,0fh
cmp bl,09h
jbe nocorrection2
add bl,07
nocorrection2:
add bl,30h
mov byte[rdi],bl
inc rdi
dec byte[count2]
jnz loop2
ret

Sample Output

speedy@comp:~$ nasm -f elf64 asgn1.asm
speedy@comp:~$ ld -o asgn1 asgn1.o
speedy@comp:~$ ./asgn1
Enter number
FEDCBA9876543210
Enter number
FEDCBA9876543210
Enter number
FEDCBA9876543210
Enter number
FEDCBA9876543210
Enter number
FEDCBA9876543210
Enter number
FEDCBA9876543210
Enter number
FEDCBA9876543210
Enter number
FEDCBA9876543210
Enter number
FEDCBA9876543210
Enter number
FEDCBA9876543210
The answer of the addition is
0000000000000009F49F49F49F49F4A0speedy@comp:~$