Heinrich Schuchardt xypron

xypron / vloxei64.v.test.c

Last active September 2, 2026 20:06

vloxei64.v.test.c

	#include <stdio.h>
	#include <stdlib.h>
	#include <stdint.h>

	#define PAGE_SIZE 4096

	// Robust 16-bit bit reversal using mask-and-swap layers (bytes -> nibbles -> pairs -> bits)
	uint16_t reverse_16_bits(uint16_t x, uint32_t bit_width) {
	// 1. Swap bytes: 0xAABB -> 0xBBAA
	x = ((x & 0x00FF) << 8) \| ((x & 0xFF00) >> 8);

xypron / Screenshot.png

Last active July 31, 2026 07:50

U-Boot: incorrect graphics output for efi-x86_app64_defconfig

xypron / pow.c

Last active July 25, 2026 07:06

Avoid poweroff on SpacemiT Com260

	// SPDX-License-Identifier: MIT
	// gcc -O2 -static -s -o pow.shutdown pow.c
	// sudo cp pow /usr/lib/systemd/system-shutdown/pow.shutdown
	#include <errno.h>
	#include <fcntl.h>
	#include <string.h>
	#include <stdio.h>
	#include <unistd.h>
	#include <linux/reboot.h>
	#include <sys/syscall.h>

xypron / linux-keymap.c

Last active April 27, 2026 14:31

linux-keymap.c

	// SPDX-License-Identifier: MIT
	/**
	* The layout of Google crosswire keyboards (compatible = "google,cros-ec-keyb")
	* are described in the device-tree by the linux,keymap property.
	*
	* The program below shows how to translate the property to human readable form.
	*/
	#include <stdio.h>

	struct keydef {

xypron / create_risc-v_vm_with_libvirt_on_jammy.md

Created March 24, 2026 14:33

Create a x86 VM with multipass

multipass launch \
  -n jammy 22.04 \
  --cpus 4 \
  --disk 16G \
  --memory 16G
multipass shell jammy

xypron / gist:83c27e97d2d5dfe531702a7aa79cffe5

Created January 17, 2025 08:44

MemTest86 EFI GUIDs

	The following GUIDs are present in /EFI/BOOT/BOOTAA64.efi of memtest86-usb.zip
	(https://www.memtest86.com/downloads/memtest86-usb.zip)

	D2 E8 A4 EB 58 38 EC 41 A2 81 26 47 BA 96 60 D0

	#define EFI_DEBUGPORT_PROTOCOL_GUID \
	{0xEBA4E8D2,0x3858,0x41EC,\
	{0xA2,0x81,0x26,0x47,0xBA,0x96,0x60,0xD0}}

	DE A9 42 90 DC 23 38 4A 96 FB 7A DE D0 80 51 6A

xypron / Makefile

Last active July 23, 2026 18:24

Makefile to create SiFive HiFive Premier P550 firmware

	#!/usr/bin/make -f
	# SPDX-License-Identifier: MIT

	UBOOT_VERSION=eab538b697011b866aba64938ef045e67fa08dc2
	OPENSBI_VERSION=EIC7X-2024.11
	NSIGN_VERSION=74e7c69b812923f68ef3eeb0c1cbbee90f80b566

	all:
	make uboot
	make sbi

xypron / DeepComputing_Roma_II_UART.jpg

Last active November 21, 2024 16:18

Roma II laptop UART

xypron / Milk-V_Mars_Boot_Source_Selection_SD_card.jpg

Last active March 8, 2024 02:22

Boot select switches on Milk-V Mars

xypron / gist:43b58aac1232e73b8eff749fbcc3b4b3

Created March 6, 2024 15:26

OpenOCD specification for PolarFire Icicle Board

	#**************************************************************************
	# Copyright (C) 2015-2020 by Microchip Technology Inc. *
	# http://www.microchip.com/support *
	# *
	# This program is free software; you can redistribute it and/or modify *
	# it under the terms of the GNU General Public License as published by *
	# the Free Software Foundation; either version 2 of the License, or *
	# (at your option) any later version. *
	# *
	# This program is distributed in the hope that it will be useful, *