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The OX Boot Loader

by Roger Doss

The OX kernel features its own custom boot loader designed to boot a 32 bit protected mode kernel.

Simple Window With Assembly

by Farhad Reza

Here, we will create a simple Window using Assembly Programming Language and also gather knowledge about various assembly language instructions.

Apex memmove - the fastest memcpy/memmove on x86/x64 ... EVER, written in C

by T. Herselman

2 years ago I went OCD on memcpy/memmove; and wrote over 140 variations (80,000 lines of code) of memmove; testing, disassembling, optimizing and benchmarking them on multiple machines. I never released the article or the code; until now! So I need to do it before I loose my mind!

PolyHook - The C++11 x86/x64 Hooking Library

by stevemk14ebr

A modern, universal, c++ hooking library.

Latest Articles

It's Assembler Time!

by Roman Nazarenko

Assembler time

Nightmare on (Overwh)Elm Street: The 64-bit Calling Convention

by CMalcheski

64-bit calling convention

Apex memmove - the fastest memcpy/memmove on x86/x64 ... EVER, written in C

by T. Herselman

2 years ago I went OCD on memcpy/memmove; and wrote over 140 variations (80,000 lines of code) of memmove; testing, disassembling, optimizing and benchmarking them on multiple machines. I never released the article or the code; until now! So I need to do it before I loose my mind!

PolyHook - The C++11 x86/x64 Hooking Library

by stevemk14ebr

A modern, universal, c++ hooking library.

All Articles

NASM

The OX Boot Loader

5 Sep 2013 by Roger Doss

The OX kernel features its own custom boot loader designed to boot a 32 bit protected mode kernel.

Simple Window With Assembly

2 Oct 2015 by Farhad Reza

Here, we will create a simple Window using Assembly Programming Language and also gather knowledge about various assembly language instructions.

Error with GNU Linker (MingW Version) ld.exe File Format Not Recognized

14 Aug 2013 by KarstenK

nasm -f aout Loader.asm -o Loader.olooks wrong. Why arent you using aout instead of elf?

Why the build assembly source in nasm don't work in win 7?

4 Mar 2016 by Richard MacCutchan

You cannot create a .com program directly from the assembler (including the fact that the source does not support it). The output should have a .exe extension.

Why the build assembly source in nasm don't work in win 7?

4 Mar 2016 by stackprogramer

i had a silly wrong!!i completed answer my friend after thinking i concluded that int 0x80 is not in windows, it should be for linux.Richard MacCutchan thanks very much.cordially your stackprogramer

Print sign in assembly

13 Mar 2017 by Kornfeld Eliyahu Peter

To print a character using BIOS interrupt 10h, you first have to set the function in AH...mov ah, 0x0emov al, '-'int 0x10If you wish us to examine your code, please paste it in to your question instead of adding a link...

X86 assembly sorting problem

16 May 2018 by OriginalGriff

We do not do your homework: it is set for a reason. It is there so that you think about what you have been told, and try to understand it. It is also there so that your tutor can identify areas where you are weak, and focus more attention on remedial action. And 3 lines of C code does not count...

X86 assembly sorting problem

16 May 2018 by Patrice T

Quote: X86 assembly sorting problem What problem do you have on this HomeWork ? We do not do your HomeWork. HomeWork is not set to test your skills at begging other people to do your work, it is set to make you think and to help your teacher to check your understanding of the courses you have...

Program ends up giving segmentation fault error

20 Dec 2020 by Patrice T

Quote: I have no clue why I am getting this error.Why is it giving the Segmentation fault (core dumped) error and how to fix it? I fear you need to go to debugger, and for 'core dumped' I think it is postmortem debugger. The first thing you will...

Program ends up giving segmentation fault error

20 Dec 2020 by Richard MacCutchan

_hell: mov rax,1 mov rdi,1 mov rsi,hell mov rdx,6 syscall ret You jump into this code from _start. After the syscall you then do a ret, but you have nowhere to return to since this code was not called as a subroutine. You need to use a call...

Assembly programming question

25 Apr 2021 by OriginalGriff

Quote: I did everything except the shifting So, you have done everything except the actual work part of the exercise? :laugh: We are more than willing to help those that are stuck: but that doesn't mean that we are here to do it all for you! We...

How do I remove this installation? Would like to install the latest build.

23 Jun 2021 by Richard MacCutchan

Your wget command has requested version 2.14.02. Try Index of /pub/nasm/releasebuilds/2.15.05[^]

Calling NASM from CreateProcess within c++

3 Jul 2013 by Oso Oluwafemi Ebenezer

I am trying to assemble a .asm source from within my cpp code using CreateProcess on NASM.When I used Windows Command Prompt nasm -f obj hello.asm, the source assembled well resulting is about 300kb .obj file but when I use "cmd /c nasm -f obj hello.asm" as createProcess 2nd parameter within...

Calling NASM from CreateProcess within c++

5 Jul 2013 by Oso Oluwafemi Ebenezer

Thank you, found my error... I wasn't closing the ofstream that writes the .asm source to disk so NASM was assembling an empty .asm file

Error with GNU Linker (MingW Version) ld.exe File Format Not Recognized

13 Aug 2013 by sid2x

I am making a simple operating System in C, (from scratch) I use a Loader.asm and a bootload.asm file for Loading my OS.kmain.c contains the basic kernel functionsand print.c contains the int main(void) function that prints some texton screen.I compile ALL the files together using this...

Why the build assembly source in nasm don't work in win 7?

4 Mar 2016 by stackprogramer

hi, my friend i build a assembly source:section .text global _start ;must be declared for linker (ld)_start: ;tells linker entry point mov edx,len ;message length mov ecx,msg ;message to write mov ebx,1 ;file descriptor (stdout) ...

Print sign in assembly

13 Mar 2017 by Member 12935107

I am working on an Operating System. I create a print function in assembly for this. When i try to print '----' with this. it does not work. My code is available on this url: ThunderEagle/printf.asm at master · Sansoft500/ThunderEagle · GitHub[^] please help me to solveWhat I have...

Print sign in assembly

13 Mar 2017 by Jochen Arndt

Code from the GitHub URL:printf: mov ah,0x0e mov bh,0x00 mov bl,0x07 next: mov al,[si] or al,al jz done int 0x10 inc si jmp next done: retThe above requires that DS:SI is pointing to a null terminated string. So you need something like this: SECTION...

How to call function from C++ in nasm

29 Sep 2019 by Richard MacCutchan

You need to use extern "C", not C++ in order to get the correct external name defined. C++ names include special characters and are not easy to predict.

How do I remove this installation? Would like to install the latest build.

23 Jun 2021 by ohaley

I copied and pasted below code with the intent of changing 2.14.02 to 2.15.05, but the moment I pasted into terminal it ran as is below: wget http://www.nasm.us/pub/nasm/releasebuilds/2.14.02/nasm-2.14.02.tar.bz2 tar xfj nasm-2.14.02.tar.bz2 cd...

What are the cons of coding a game engine in assembly?

6 Nov 2023 by Bob Blake from Unknown

I am planning to build a game engine that operates at a very low level without any abstractions and to do so, I was going to use NASM X86/X64. Is this a good choice or should I use a higher level language? I want to get the pros and cons of...

What are the cons of coding a game engine in assembly?

5 Nov 2023 by Dave Kreskowiak

You do know that Windows abstracts all the hardware from application code, right? You would have to go through DirectX to do anything with the hardware, but even DirectX is another abstraction layer.

Program ends up giving segmentation fault error

20 Dec 2020 by User 14731409

section .data hell db "Hello",10 bye db "Bye",10 section .text global _start _start: mov r10,1 cmp r10,1 je _hell cmp r10,0 jne _bye mov rax,60 mov rdi,0 syscall _hell: mov rax,1 mov rdi,1 mov rsi,hell mov rdx,6 syscall ret _bye: mov rax,1...

Apex memmove - the fastest memcpy/memmove on x86/x64 ... EVER, written in C

5 Jul 2016 by T. Herselman

2 years ago I went OCD on memcpy/memmove; and wrote over 140 variations (80,000 lines of code) of memmove; testing, disassembling, optimizing and benchmarking them on multiple machines. I never released the article or the code; until now! So I need to do it before I loose my mind!

PolyHook - The C++11 x86/x64 Hooking Library

17 May 2016 by stevemk14ebr

A modern, universal, c++ hooking library.

Nightmare on (Overwh)Elm Street: The 64-bit Calling Convention

13 May 2017 by CMalcheski

64-bit calling convention

It's Assembler Time!

8 Jul 2017 by Roman Nazarenko

Assembler time

X86 assembly sorting problem

16 May 2018 by Member 13831057

Build a software project made of individual modules as shown in the diagram on one of the following pages. The diagram shows the calling hierarchy. It does not show the sequence of calls. The sequence (ordering) of execution can be derived from the sample execution on the next page. Sample...

How to call function from C++ in nasm

29 Sep 2019 by Member 14160360

u want to call function from c++ in nasm in this function I declare object from class What I have tried: I tried this code in nasm file extern kmain and this code in c++ file extern "c++" kmain ; but it's don't solve the problem and always I get this error message undefined reference to _kmain