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Peter Cordes
Peter Cordes
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x86-64 Assembly - Sum of numbersmultiples of 3 or 5

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sdasdadas
sdasdadas
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The purpose of the code is to sum all numbers from [0, 1000) that are divisible by 3 or 5.

The code can be run using make RUN=euler_1.

extern printf global main section .data fmt: db "%d", 0x0a, 0 section .text ;; main - Calculate the sum of all numbers between [0, 1000) that are divisible ;; by 3 or 5. ;; sum : R8 main: ; sum = 0 mov r8, 0 ; for i in [0, 1000) { mov rcx, 0 for0: ; if i % 3 == 0 or i % 5 == 0 { ; i % 3 == 0 mov rax, rcx mov rdx, 0 mov r9, 3 div r9 test rdx, rdx jne if01 ; sum = sum + i add r8, rcx jmp if0 if01: ; i % 5 == 0 mov rax, rcx mov rdx, 0 mov r9, 5 div r9 test rdx, rdx jne if0 ; sum = sum + i add r8, rcx jmp if0 ; } if0: inc rcx cmp rcx, 1000 jl for0 ; } ; printf("%d", sum) lea rdi, [rel fmt] mov rsi, r8 mov rax, 0 call printf ; sys_exit(0) mov rdi, 0 mov rax, 60 syscall

The code can be run using make RUN=euler_1.

extern printf global main section .data fmt: db "%d", 0x0a, 0 section .text ;; main - Calculate the sum of all numbers between [0, 1000) that are divisible by 3 or 5. ;; sum : R8 main: ; sum = 0 mov r8, 0 ; for i in [0, 1000) { mov rcx, 0 for0: ; if i % 3 == 0 or i % 5 == 0 { ; i % 3 == 0 mov rax, rcx mov rdx, 0 mov r9, 3 div r9 test rdx, rdx jne if01 ; sum = sum + i add r8, rcx jmp if0 if01: ; i % 5 == 0 mov rax, rcx mov rdx, 0 mov r9, 5 div r9 test rdx, rdx jne if0 ; sum = sum + i add r8, rcx jmp if0 ; } if0: inc rcx cmp rcx, 1000 jl for0 ; } ; printf("%d", sum) lea rdi, [rel fmt] mov rsi, r8 mov rax, 0 call printf ; sys_exit(0) mov rdi, 0 mov rax, 60 syscall

The purpose of the code is to sum all numbers from [0, 1000) that are divisible by 3 or 5.

The code can be run using make RUN=euler_1.

extern printf global main section .data fmt: db "%d", 0x0a, 0 section .text ;; main - Calculate the sum of all numbers between [0, 1000) that are divisible ;; by 3 or 5. ;; sum : R8 main: ; sum = 0 mov r8, 0 ; for i in [0, 1000) { mov rcx, 0 for0: ; if i % 3 == 0 or i % 5 == 0 { ; i % 3 == 0 mov rax, rcx mov rdx, 0 mov r9, 3 div r9 test rdx, rdx jne if01 ; sum = sum + i add r8, rcx jmp if0 if01: ; i % 5 == 0 mov rax, rcx mov rdx, 0 mov r9, 5 div r9 test rdx, rdx jne if0 ; sum = sum + i add r8, rcx jmp if0 ; } if0: inc rcx cmp rcx, 1000 jl for0 ; } ; printf("%d", sum) lea rdi, [rel fmt] mov rsi, r8 mov rax, 0 call printf ; sys_exit(0) mov rdi, 0 mov rax, 60 syscall
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sdasdadas
sdasdadas
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x86-64 Assembly - Sum of numbers

I'm trying to learn some basic x86 assembly and so I've begun solving Project Euler problems. I was hoping for some critique of my code that, hopefully, includes either the efficiency of the operations or the readability / style of the code itself. I will provide the Makefile for Linux 64 bit.

The code can be run using make RUN=euler_1.

NB:

I am aware that most compilers replace modulos of known numbers with some combination of mov and shr to avoid the integer division. For example, see this thread.

Makefile

.PHONY: clean all: $(RUN).elf ./$^ %.elf: %.o ld $^ -o $@ -lc -e main -dynamic-linker /lib64/ld-linux-x86-64.so.2 %.o: %.asm nasm -f elf64 $^ clean: rm -f *.o *.elf

euler_1.asm

extern printf global main section .data fmt: db "%d", 0x0a, 0 section .text ;; main - Calculate the sum of all numbers between [0, 1000) that are divisible by 3 or 5. ;; sum : R8 main: ; sum = 0 mov r8, 0 ; for i in [0, 1000) { mov rcx, 0 for0: ; if i % 3 == 0 or i % 5 == 0 { ; i % 3 == 0 mov rax, rcx mov rdx, 0 mov r9, 3 div r9 test rdx, rdx jne if01 ; sum = sum + i add r8, rcx jmp if0 if01: ; i % 5 == 0 mov rax, rcx mov rdx, 0 mov r9, 5 div r9 test rdx, rdx jne if0 ; sum = sum + i add r8, rcx jmp if0 ; } if0: inc rcx cmp rcx, 1000 jl for0 ; } ; printf("%d", sum) lea rdi, [rel fmt] mov rsi, r8 mov rax, 0 call printf ; sys_exit(0) mov rdi, 0 mov rax, 60 syscall