Questions tagged [assembly]

An assembly language is a low-level programming language for a computer, or other programmable device, in which there is a very strong (generally one-to-one) correspondence between the language and the architecture's machine code instructions.

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9
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1answer
4k views

Iterating string characters and passing them to a BIOS API

Which style of printing strings from the SI registry in NASM is more correct? I'm learning assembly and x86 architecture, but I'm rather new in it, so I've prepared two styles (in NASM) of printing a ...
8
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1answer
282 views

Embedded conditional code compaction

I'm porting some AVR code from PROGMEM/PGM_P to __flash, and I want to reduce the amount of ...
5
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1answer
769 views

Is this CPUID parser ideal for any usage?

NOTE: I'm not perfectly sure of some of the parsed data, so any corrections are more than welcome. Parser (cpuid.c): ...
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2answers
586 views

Polling for Nios 2

The program listens to the Altera FPGA DE2 board's keys that can start and stop and reset a counter: ...
9
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3answers
5k views

x86 strcpy implementation

I got about 4 days of assembly knowledge, so I need a review on this strcpy function and if it can be done better (at least I have the feeling). Full code (with ...
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1answer
226 views

Assembler PIC programming, is this correct? [closed]

The question is: Write the following pseudo in assembler code: ...
16
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2answers
673 views

x64 assembly clearmem / zeromem

I've just started learning assembly yesterday, and the first useful thing I've written is a clearmem function. I'm looking for general feedback regarding my coding ...
7
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1answer
937 views

Fastest fill memory with specified 64-bit value

I need to fast fill a memory block in C#, so I wrote something like this (in Free Pascal Compiler + Lazarus in 64 bit mode): ...
6
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1answer
6k views

Calculating prime factors in MIPS assembly

The goal of this was to be able to enter any number and print out the prime factors of that number. Are there any shorter ways of writing this code? I'm not very familiar with low-level syntax and was ...
7
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1answer
546 views

RC4 in 8051 assembly optimization

I've been playing around with 8051 assembly lately and thought I would make a little project of implementing RC4, since it is pretty interesting and the algorithm doesn't seem too hard. Plus, taking <...
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2answers
3k views

GCD/LCM calculator in x86 NASM assembly

After creating a similar program in C++, I've decided to try to write it in x86 assembly language (the type of assembly I was taught in college). I'd like to receive feedback regarding syntax and ...
5
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1answer
1k views

Computing a mathematical function in MIPS assembly

This code computes the function (3x^2-4x+16) / (5x^2+2x-4). I ran the program and it works, but I am fairly new to assembly language and am not quite sure how to ...
3
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1answer
712 views

Trying to improve and better understand Intel SSE intrinsics

I've been writing a collection of signal processing function optimized with SSE intrinsics (mostly for audio processing). Here is a linear interpolation function I wrote. It works well and is quite ...
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1answer
2k views

Nios 2 interrupt handler

This is homework for which we have prepared Nios 2 assembly: ...
7
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1answer
462 views

Writing SIMD libraries for C++ on FASM in x86-64 Linux

I have recently started a project of SIMD libraries development for C++ on FASM for x86-64 Linux. I would be glad to hear any opinion or feedback about the project, cleanness of the code and ...
8
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1answer
1k views

Listing the first five perfect numbers in MIPS assembly

I've done some programming in the past, but I'm new to MIPS, which I'm trying to learn on my own. This program lists the first five perfect numbers. It uses the Lucas-Lehmer and Miller-Rabin primality ...
5
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1answer
335 views

First steps with amd64 assembly

I try to learn amd64 assembler. This is the first thing I tried. This piece of assembly should replicate the functionality of the following piece of C code, which turns a binary sha-256 hash into a ...
5
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1answer
624 views

The beginnings of a bootloader using GNU-based tools

This is a personal project of mine. I am currently in the research phase of developing my own bootloader that will be used to load a single task operating system. I am far away from the final goal, ...
4
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1answer
2k views

SSE2 assembly optimization - multiply unsigned shorts and add the result

I am attempting to optimize a piece of C code which aims to multiply a series of pairs of unsigned shorts and add the result. I am only concerned about the high 16 bits of the result, and I can ...
102
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9answers
39k views

Fastest way to clamp an integer to the range 0-255

I'm working on some image processing code that can generate pixel values outside of the normal range of 0 to 255, and I'd like to clamp them back into the valid range. I know that there are saturating ...
3
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2answers
7k views

Correct User Input - x86 Linux Assembly [closed]

So I am working on an x86 Assembly program for Linux using NASM. This program basically asks the user for their name and their favorite color. After doing this and storing the two strings in variables ...
7
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1answer
359 views

Bilinear scaling using SSE2 on Core 2 CPUs

I am looking for some help with improving this bilinear scaling SSE2 code on Core 2 CPUs. On my Atom N270 and on an i7, this code is about 2x faster than the MMX code. But under Core 2 CPUs, it is ...

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