yalue’s gists

yalue / mandelbrot.S

Last active July 30, 2025 18:59

Mandelbrot set printed to stdout on Linux in ARM32 assembly

	// Assemble using:
	// arm-linux-gnueabihf-as -mfpu=neon -o mandelbrot.o mandelbrot.S
	// arm-linux-gnueabihf-ld -o mandelbrot mandelbrot.o
	.syntax unified

	.section .data
	message:
	canvas_width = 40
	canvas_height = 30
	max_iters = 100

yalue / ARM mnemonics.txt

Created January 15, 2025 17:05

List of ARM mnemonics. May include some ARM64 mnemonics, probably missing a few.

yalue / ffmpeg_reencode.rb

Created January 11, 2025 01:57

Ruby snippet for reencoding .mp4 videos using ffmpeg

	# Returns the file path with extension removed
	def strip_extension(filepath)
	File.join(
	File.dirname(filepath),
	File.basename(filepath, File.extname(filepath))
	)
	end

	# Re-encodes the given file as .mp4 using libh264 and MP3 audio. Returns the
	# filename of the new file.

yalue / litmus_config.txt

Last active March 2, 2022 15:13

The config file for building my version of litmus at commit d74240785e132966b9ce4f35a594ebf4440e4757

	#
	# Automatically generated file; DO NOT EDIT.
	# Linux/x86 5.16.0-rc6 Kernel Configuration
	#
	CONFIG_CC_VERSION_TEXT="gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0"
	CONFIG_CC_IS_GCC=y
	CONFIG_GCC_VERSION=70500
	CONFIG_CLANG_VERSION=0
	CONFIG_AS_IS_GNU=y
	CONFIG_AS_VERSION=23000

yalue / litmus-5.16-rc7-config

Created February 3, 2022 21:00

The config file I was using for my (mostly) working build of my LITMUS update.

	#
	# Automatically generated file; DO NOT EDIT.
	# Linux/x86 5.16.0-rc6 Kernel Configuration
	#
	CONFIG_CC_VERSION_TEXT="gcc (Debian 10.2.1-6) 10.2.1 20210110"
	CONFIG_CC_IS_GCC=y
	CONFIG_GCC_VERSION=100201
	CONFIG_CLANG_VERSION=0
	CONFIG_AS_IS_GNU=y
	CONFIG_AS_VERSION=23502

yalue / string_replace.c

Created February 1, 2022 16:32

Just a quick string replacement function in C, so I don't need to think about it next time I need it.

	#include <stdint.h>
	#include <string.h>

	// Replaces all instances of the string match in input with r. Returns a new
	// null-terminated string, or NULL on error. The returned string must be freed
	// by the caller when no longer needed. Even if no replacements are made, this
	// will return a new copy of the input string.
	char* StringReplace(const char input, const char match, const char *r) {
	char *input_pos = NULL;
	const char *prev_input_pos = NULL;

yalue / litmus_porting_notes.txt

Last active March 2, 2022 14:29

Notes I made while porting LITMUS^RT to Linux 5.16.

	To compare Joshua's changes vs. the baseline 5.4 he used:

	https://github.com/JoshuaJB/litmus-rt/compare/b90344f7d6000deba0709d75225f30cbf79ec2f0...55ce62849f94dd9c9fc0a5397b4f8cf40b40a324

	General notes:

	- The "state" field in task_struct is now __state and should be accessed using
	the READ_ONCE and WRITE_ONCE accessors, or other macros from sched.h.

	- The "lock" field in "struct rq" is now __lock, and should be

yalue / bit_accessor.h

Created October 11, 2021 00:30

A mega-union for directly accessing any bits in a uint64_t in C.

	#ifndef BIT_ACCESSOR_H
	#define BIT_ACCESSOR_H
	#include <stdio.h>
	#ifdef __cplusplus
	extern "C" {
	#endif

	// This header defines the BitAccessor type, which can be used for setting any
	// series of consecutive bits in a uint64_t. For example, to set bits 7-13 in
	// a 64-bit value:

yalue / write_to_pipe.c

Created November 12, 2020 20:49

An example of writing to a child process' stdin, in C.

	#include <errno.h>
	#include <stdio.h>
	#include <string.h>
	#include <unistd.h>

	// A minimal-ish example of writing data to a child process' stdin.
	int main(int argc, char **argv) {
	char print_buffer[256];
	int stdin_pipe[2];
	int result;

yalue / AMD driver fail.txt

Created August 14, 2020 21:22

dmesg output when I tried running "import torch"

	[ 347.582485] BUG: kernel NULL pointer dereference, address: 0000000000000028
	[ 347.582489] #PF: supervisor write access in kernel mode
	[ 347.582490] #PF: error_code(0x0002) - not-present page
	[ 347.582491] PGD 0 P4D 0
	[ 347.582494] Oops: 0002 [#1] PREEMPT SMP
	[ 347.582496] CPU: 15 PID: 7937 Comm: python Not tainted 5.8.0+ #1
	[ 347.582497] Hardware name: Dell Inc. Precision Tower 7910/0NK5PH, BIOS A13 05/20/2016
	[ 347.582626] RIP: 0010:amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x48d/0x900 [amdgpu]
	[ 347.582628] Code: 03 c1 e8 96 bf b2 dd e9 94 fd ff ff 83 bd 40 ff ff ff 02 48 8b 85 78 ff ff ff 75 12 48 8b 90 30 02 00 00 4c 89 b0 90 02 00 00 <4c> 89 72 28 48 8b 13 48 83 bd 48 ff ff ff 00 48 89 90 90 03 00 00
	[ 347.582629] RSP: 0018:ffff9c00c2037cc0 EFLAGS: 00010246

Nathan O yalue