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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1answer
287 views
x64 Assembly - checking for largest prime factor
Using x64 assembly, I solved the Largest Prime Factor problem on Project Euler.
The problem is as follows:
The prime factors of 13195 are 5, 7, 13 and 29.
What is the largest prime factor of ...
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1answer
35 views
Inline assembly correctness (especially __volatile__)
Here's my inline-assembly functions, which is used my x86 32bit kernel.
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3answers
185 views
Integer square root in x86 assembly (NASM)
This program calculates the square root of an unsigned 32-bit number with some bit fiddling to get a very close approximation, then one iteration of the Babylonian method to get an exact value. I ...
6
votes
2answers
122 views
String length calculation implementation in Assembly (NASM)
I just made a working implementation of calculating a string's length, but I'm not exactly sure it's the most efficient way. I divide the string up in blocks of four bytes each (32 bits), and add 4 to ...
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votes
3answers
287 views
32-bit factorial calculator in x86 NASM assembly
This program calculates the factorial of a given positive number.
This is how it handles input:
if negative, terminate program
if 0-2, display input without calculating
if greater than or equal to ...
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votes
0answers
28 views
Properly handling NOT operators for nodejs
Converting assembly code to nodejs,
Having the assembly code:
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19
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1answer
303 views
Stack implemented using linked list in x86_64 assembly
I wrote a stack implementation using a singly linked list in x86_64 assembly. This stack supports the usual push/pop operations ...
11
votes
1answer
194 views
Linux NASM assembly linked list implementation
Inspired by all of the lovely linked lists lately, I decided to implement one in assembly language. This code maintains two linked lists - one is a free store and the other is the active linked list. ...
4
votes
2answers
106 views
Is this C++ program correctly implemented in SSE?
I have to implement a simple program in SSE, and I don't know if I have done it in the right way (it's my first program in SSE).
This is the C++ program:
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4
votes
2answers
240 views
Alp in MASM 8086
If the number is present, the output should show the numbers that are not present.
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8
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1answer
88 views
Switch-case Monstrosity for CPU Emulator
I am still working on A Z80 CPU emulator and I have decided to prototype it in javascript and then translate it into a faster language, It might be ported to C but more likely is Java - this means I ...
7
votes
2answers
232 views
Search procedure to find inputted DWORD in MASM Array
Is there any way to make this more efficient?
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3
votes
1answer
67 views
Counter in FASM assembly
I am making a simple counter in assembly. It counts to a billion and exits. However, the performance of this is really horrible. A Java application (that does the same) outperforms it by around 10x. ...
7
votes
2answers
109 views
Improvements/suggestions for my CPU emulator
I am trying to emulate a basic CPU (Z80) as close as possible. It currently does not read real assembly code, but that will be implemented. If you have any views on how that could be implemented, ...
7
votes
1answer
211 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 ...
7
votes
1answer
141 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 ...
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vote
0answers
111 views
x86_64 assembly print integer stack allocation [closed]
I have made this simple assembly program that prints an integer in hexadecimal.
It works, but I don't understand why it works with only a stack size of 15, when to print a 64 bit integer including ...
4
votes
1answer
203 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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vote
2answers
184 views
Please review polling for Nios 2
The program listens to the Altera FPGA DE2 board's keys that can start and stop and reset a counter:
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6
votes
3answers
407 views
x86 strcpy - can this be shortened?
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 the test included):
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1answer
96 views
Assembler PIC programming, is this correct? [closed]
The question is:
Write the following pseudo in assembler code:
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10
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2answers
199 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 ...
3
votes
1answer
228 views
Fastest fill memory with specified 64-bit value
I need to fast fill some memory block in C#, so I wrote something like this (in Ffree Pascal COmpiler + Lazarus in 64 bit mode):
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6
votes
1answer
636 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 ...
6
votes
1answer
242 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 ...
8
votes
2answers
539 views
GCD/LCM calculator in x86 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
votes
1answer
121 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
votes
1answer
195 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 ...
2
votes
1answer
535 views
Please review assembly for Nios 2 interrupts
This is homework for which we have prepared Nios 2 assembly and C:
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7
votes
1answer
289 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 ...
7
votes
1answer
325 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
votes
1answer
229 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
votes
1answer
223 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
votes
1answer
1k 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 ...
42
votes
8answers
9k 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 ...
1
vote
2answers
557 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 ...
6
votes
1answer
280 views
Improving this bilinear scaling SSE2 code 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 ...
