I am trying to write an assembly program that takes integers and adds them all together and spits out the sum. However my code currently just has the same block of code repeating. How can I turn this into a cleaner, shorter code while maintaining the same functionality?
section .rodata prompt1 db "Please enter a number: ",0 ; 0 is null character prompt2 db "Enter another number: ",0 format_str db "The sum is: %ld.",10,0 ; 10 is LF num_format db "%ld",0 section .text global main ; main and _start are both valid entry points extern printf, scanf ; these will be linked in from glibc main: ; prologue push rbp ; save base pointer to the stack mov rbp, rsp ; base pointer = stack pointer sub rsp, 80 ; make room for integers on the stack push rbx ; push callee saved registers onto the stack push r12 ; push automatically decrements stack pointer push r13 push r14 push r15 pushfq ; push register flags onto the stack ; prompt for first integer mov rdi, dword prompt1 ; double word is 4 bytes; a word is 2 bytes xor rax, rax ; rax is return value register - zero it out call printf ; call the C function from glibc lea rsi, [rbp-8] ; load effective address - this instruction mov rdi, dword num_format ; load rdi with address to format string xor rax, rax ; zero out return value register call scanf ; call C function ; scanf reads the input as an integer ; prompt for other integer mov rdi, dword prompt2 xor rax, rax call printf lea rsi, [rbp-16] ; read number mov rdi, dword num_format xor rax, rax call scanf ; prompt for other integer mov rdi, dword prompt2 xor rax, rax call printf lea rsi, [rbp-24] ; read number mov rdi, dword num_format xor rax, rax call scanf ; prompt for other integer mov rdi, dword prompt2 xor rax, rax call printf lea rsi, [rbp-32] ; read number mov rdi, dword num_format xor rax, rax call scanf ; prompt for other integer mov rdi, dword prompt2 xor rax, rax call printf lea rsi, [rbp-40] ; read number mov rdi, dword num_format xor rax, rax call scanf ; prompt for other integer mov rdi, dword prompt2 xor rax, rax call printf lea rsi, [rbp-48] ; read number mov rdi, dword num_format xor rax, rax call scanf ; prompt for other integer mov rdi, dword prompt2 xor rax, rax call printf lea rsi, [rbp-56] ; read number mov rdi, dword num_format xor rax, rax call scanf ; prompt for other integer mov rdi, dword prompt2 xor rax, rax call printf lea rsi, [rbp-64] ; read number mov rdi, dword num_format xor rax, rax call scanf ; prompt for other integer mov rdi, dword prompt2 xor rax, rax call printf lea rsi, [rbp-72] ; read number mov rdi, dword num_format xor rax, rax call scanf ; prompt for other integer mov rdi, dword prompt2 xor rax, rax call printf lea rsi, [rbp-80] ; read number mov rdi, dword num_format xor rax, rax call scanf ; add all numbers together xor rbx, rbx ; sum = 0 mov rcx, [rbp-8] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rcx, [rbp-16] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rcx, [rbp-24] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rcx, [rbp-32] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rcx, [rbp-40] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rcx, [rbp-48] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rcx, [rbp-56] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rcx, [rbp-64] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rcx, [rbp-72] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rcx, [rbp-80] ; RBX = number add rbx, rcx ; add num + num - store in rbx mov rsi, rbx mov rdi, dword format_str xor rax, rax ; rax is return value register - zero it out call printf ; call the C function from glibc exit: ; epilogue popfq pop r15 pop r14 pop r13 pop r12 pop rbx add rsp, 80 ; set back the stack level leave ret If you have a nasm compiler you can use these commands to compile and run the code.
nasm -f elf64 -g -F dwarf lab9.asm # -g -F dwarf adds debugging stuff gcc -o lab9 lab9.o -lc
