Questions tagged [assembly]
Use this for code written in any assembly language. Assembly-language questions also need a tag to indicate the target processor's instruction set architecture (ISA).
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Mac M1 .BF Compiler in Rust
I'm writing a brainfuck compiler in rust, that takes brainfuck instructions and converts them to a very basic assembly form, and then compiles that into binary, if you are not familiar with brainfuck ...
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The core of the assembler (the part of the assembler that actually converts mnemonics to opcodes) is hard to follow due to many if-branchings
For my Bachelor thesis, I made a PicoBlaze Assembler and Emulator in JavaScript. I've discussed it on many Internet forums, and quite a few people have complained that the core of my assembler is hard-...
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Rust implementation of fibers
I am still new to rust, so any comment about what is the rust way of doing things is welcome. this is a hand-rolled implementation of fibers or user-land context-switching.
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Functions to simplify printing strings and numbers in amd64 Assembly
I'm new to Assembly, and this is my very first "project" in Assembly. I wanted to store data (numbers) on the stack, then access and display them. Eventually, this "experiment" of ...
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Number guessing game for x86
I'm new to assembly and I've just finished this guessing game that I wanted to make to improve my skills in this language. It runs in a Unix environment and does the following:
generates a random ...
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Speed up strlen using SWAR in x86-64 assembly
The asm function strlen receives the link to a string as a char - Array. To do so, the function may use SWAR on general purpose register, but without using ...
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part of a c++ program which mods a game using code injection
https://github.com/speedrun-program/amnesia_load_screen_tool/blob/main/code_injection.cpp
https://github.com/speedrun-program/amnesia_load_screen_tool/blob/main/file_helper.h
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`strdup` re-implementation in assembly
I am posting a message here because I am new to assembly programming. My goal today was to re-code strdup in assembly, so to save my first parameter which is a ...
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Replace specific characters (CR and LF) in a file
Context
This program has been created to "fix" files originating from Cobol databases. In Cobol, files extracted via something called a "copy" have the same number of characters ...
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Perform a permutation on an array in MIPS assembly
I’m currently studying computer science at university and I’d been tasked with writing a MIPS assembly program that performs a permutation on an array. I’m asking here because my code actually worked ...
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Base64 Encoder in Assembly X86-64
I am a beginner in assembly and would like to know ways I could improve my code. I am talking more about assembly specific things and less the logic e.g. what I could've written better, like loops
<...
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Multiply two huge base-10 numbers in assembly
This post is a second part of my original post, Add two huge base-10 numbers, which deals with adding two huge base-10 numbers. However, in this case, I'm multiplying two non-negative whole numbers. ...
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Add two huge base-10 numbers
This is some assembly code I've written to add two base-10 numbers. The input and output are represented as null-terminated ASCII strings, with digits in big-endian order.
I have also provided ...
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Remove leading zeroes from the beginning of a string
I want to remove leading zeroes (for a big integer library I'm currently making) in numbers represented as char arrays.
I chose assembly for speed, but in order to simplify making the algorithm and ...
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Increment a binary number represented as a string
I'm an amateur at assembly, but am trying to get better at it. For fun, I decided to write code that takes in a char array and increments the number represented in binary.
Here are a few input-output ...
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Optimizing Netwide Assembler codes in Microsoft Windows
I am a novice in assembler programing, I will will appreciate if someone could review these NASM assembler code for me. Is about encoder decoder.
The encoder performs the following:
pads the ...
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"Hello world" in x64 assembly for Windows - Shadow space / Stack alignment
I`m currently trying to delve into x64 assembly under windows using NASM, and created a minimalistic "Hello World" application.
It is mainly meant as an educational resource for me and ...
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Test and set a bit atomically using inline aarch64 assembly
The code below has been a vehicle for learning the syntax of inline assembly for gcc/clang and that is the focus of my question. In addition to anything else that I've missed I would also like ...
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Hack assembler/disassembler in x86_64 assembly language
Starting from this answer I thought I would show a fully worked example of how to create a data-driven version of the assembler for the Hack assembly language. As I noted in that answer, having ...
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First assembly program: working with strings and integers
I started learning assembly some days ago and I wrote my first program today. Nothing exceptional here: some user inputs, strings manipulations, integer to string conversion etc... The only purpose ...
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Assembler made in assembly
I made an assembler for the "hack" assembly language, here's an example of what it looks like:
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File dump in assembly
This is a file dump program written in assembly that displays 320 bytes at a time in 20 lines.
It shows the hex code for each character and also the string
At the start of the program it asks for the ...
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441
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Sieve of Eratosthenes in x86 assembly
Hello I made a sieve of Eratosthenes algorithm on x86 assembly using NASM.
The highest number it can take is about 2 million and it takes like 2 seconds to complete.
Here's the code:
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Sum two vectors in x86 assembly
I recently made a program with C++ and ASM. Can anyone help me make this code a more efficient one, in the ASM part or both.
I would really appreciate it because I don't know every ASM instruction and ...
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Base64 encoder in Assembly x86-64 Linux language
We were asked to create a Base64 encoder for Assembly x86-64 on Linux. Was wondering how my code below could be improved, be it notation or anything else. We only had Assembly for 3 months so I'm not ...
user197730
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Single-threaded coroutine in C (Linux x86-64)
Background Story
I crafted a simple single-threaded coroutine in C, running on Linux x86-64.
Short Technical Explanation
1) Task
There are two types of tasks in this implementation.
Main task. This ...
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A Brainfuck compiler that creates a small x86_64 Linux executable from scratch
This program compiles Brainfuck source code to an x86_64 ELF executable. It doesn't rely on any backend, just raw binary stream to a functional executable.
In the implementation, each cell holds an 8-...
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Minimal `printf` for integer types in x86 assembly
I'm writing a minimal C runtime targeting an old 32-bit Windows XP machine as a personal project. The C runtime provided by compilers is quite bloated. I wouldn't mind some library bloats up to ...
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Beating the compiler with a simple program finding the longest collatz sequence
I found this question in Stackoverflow asking why his/her assembly program isn't faster than the C++ program. In his/her assembly program I saw the lines ...
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RC4 stream cipher in ARM Assembly
Below is a complete implementation of RC4 in ARM assembly. Unit tests pass, including comparison to C implementation and to published test vectors.
I'm appreciative of all feedback, comments (things ...
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MIPS-32 assembly: Determine if n is prime
I'm new to assembly and I'm learning on my own, so I'd appreciate the feedback. My priorities are correctness (on all MIPS-32 with sllv) > speed > readability ...
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Project Euler 1 (sum of multiples of 3 or 5) in ARM Assembly
Project Euler #1 asks:
Find the sum of all the multiples of 3 or 5 below 1000.
In ARM Assembly;
I did this in 3 loops, which avoids any MOD or DIV.
Each loop is written out, without a common ...
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Arm Assembly Tokenize String (strtok()), Load Move, Add Efficiency
Dabbling a bit more with arm assembly, I wrote a few functions to handle string splitting. The goal was to write a few reusable functions that could be combined to emulate (roughly) what C ...
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Writing an x64 Code Emitter to eventually make a full fledged Assembler like NASM
As the title suggests, I'm writing an x64 Code Emitter. Right now I've only encoded 1 instruction (The add instruction). I want to know if this API can be improved at all.
This is how you I use it.
<...
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GNU assembly (AT&T syntax) bootloader load the next sector from floppy
I'm playing with the Real mode and was trying to code something when suddenly I exceeded the 510 boundary (.org 510) of the <...
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Hack machine language assembler as required for project 6 of Nand2Tetris
This is the implementation of the Assembler required to parse source code written in the Hack Machine Language and output it to a 16-bit binary file.
After writing one go in Swift, I decided I wanted ...
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Printing one to ten in (GAS/AT&T x86/x64) assembly
I've started my journey of learning assembly on my Mac. As a start, I've decided to write a program to print the numbers one through ten to the console, then a final string signifying the end of the ...
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4x4 double precision matrix multiply using AVX intrinsics (inc. benchmarks)
Benchmark
An optimised 4x4 double precision matrix multiply using intel AVX intrinsics. Two different variations.
Gist
For quick benchmark (with a compatible system) copy paste the command below. Runs ...
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Assembler. Algorithm for incrementing a decimal number
I share an algorithm that I have written myself. It is useful for incrementing any digit of a decimal number. That way, a conversion to decimal is not necessary.
Please excuse the mistakes. I am ...
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FizzBuzz in arm64
I made a FizzBuzz program in arm64; I print out the values in hex instead of decimal. This was the first arm64 program I made and I'm looking for advice on how I can improve it.
The code to print out ...
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81 variations of the rounded rectangle
If we apply outward curving, inward curving, and no curving at all, individually to each of the 4 corners of the rectangle, we get next 81 variations:
The code implements next BASIC command:
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Binary to hex in ARM64 SIMD assembly
As an exercise in learning ARM64 assembly (aka AArch64), I wrote this function to convert 64-bit binary to hexadecimal with SIMD instructions. I'm most interested in feedback on the algorithm, ...
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setjmp and longjmp implementation in mmix
I've written an implementation of setjmp and longjmp in MMIX (assuming no name mangling).
I also hand-assembled it.
Are there any mistakes anyone can spot?
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MASM) assembly implementation of recursive Fibonacci
I'm trying to teach myself assembly via MASM, below is my first implementation of the recursive form of the fibonacci sequence. I timed it against an equivalent C implementation in release mode and ...
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Decimal to binary conversion in ARM assembly
I'm "playing" with ARM assembly on a Raspberry Pi, reading various tutorials and posts to help - no, it's not a college assignment, I'm too old for college! I'm pleased with getting the ...
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Writing a recursive factorial function in x86-64
The following assembly program works to print the factorial of a number:
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447
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Fork Bomb virus in Assembly
I made a fork bomb virus in Assembly. Now, I want to make my code better.
Here is my code:
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Fastest (in clock cycles) 16-bit x 16-bit unsigned integer division algorithm for ATMEGA1284?
I am trying to create an optimized 16-bit division algorithm for the AVR ATMEGA1284. The goal is to reduce the number of clock cycles as much as possible.
AVR INSTRUCTION SET MANUAL:
https://ww1....
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Converting decimal to binary in Assembly
The longest example program in my PicoBlaze Simulator in JavaScript is this decimal-to-binary converter:
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