Daniel Näslund dannas

Multi-dimensional array views for systems programmers

As C programmers, most of us think of pointer arithmetic for multi-dimensional arrays in a nested way:

The address for a 1-dimensional array is base + x. The address for a 2-dimensional array is base + x + y*x_size for row-major layout and base + y + x*y_size for column-major layout. The address for a 3-dimensional array is base + x + (y + z*y_size)*x_size for row-column-major layout. And so on.

Papers I like Pt. 1 Papers I like Pt. 2

Let's start meta:

Lamport - State the Problem Before Describing the Solution (1978). … 1-page memo. Read it.
Herlihy - Wait-free synchronization (1991) … Truly seminal. Lucid + enough good ideas for 4 papers easily.
Cook - How complex systems fail (1998) … 4 pages that anyone working on/with complex systems should read.

My Vim-related gists

Long-form

API Design: Coroutines APIs (Janurary-2017)

I am currently dealing with a lot of libraries at work. Both third party as well as libraries written or being currently in process of being written by me. I absolutely love writing and working with libraries. Especially if they present or bring me to either a new or different approach to solve a problem. Or at least provide a different view.

Over time I noticed however that quite regulary we had to decide that we cannot use a third party library. Often it is the usual reason.

Memory Optimization (Christer Ericson, GDC 2003)
http://realtimecollisiondetection.net/pubs/GDC03_Ericson_Memory_Optimization.ppt

Cache coherency primer (Fabian Giesen)
https://fgiesen.wordpress.com/2014/07/07/cache-coherency/

Code Clinic 2015: How to Write Code the Compiler Can Actually Optimize (Mike Acton)
http://gdcvault.com/play/1021866/Code-Clinic-2015-How-to

	#!/usr/bin/awk -f

	# This program is a copy of guff, a plot device. https://github.com/silentbicycle/guff
	# My copy here is written in awk instead of C, has no compelling benefit.
	# Public domain. @thingskatedid

	# Run as awk -v x=xyz ... or env variables for stuff?
	# Assumptions: the data is evenly spaced along the x-axis

	# TODO: moving average

	#if _WIN32
	struct Timer {
	LARGE_INTEGER win32_freq;
	LARGE_INTEGER win32_start;

	Timer() {
	QueryPerformanceFrequency(&win32_freq);
	win32_start.QuadPart = 0;
	}

	%%-----------------------------------------------------------------------
	%% Make your own quadrille, graph, hex, etc paper!
	%% Uses the pgf/TikZ package for LaTeX, which should be part of
	%% any modern TeX installation.
	%% Email: mcnees@gmail.com
	%% Twitter: @mcnees
	%%-----------------------------------------------------------------------

	\documentclass[11pt]{article}

	enum { BMAX = 32, BCUT = BMAX / 2, BHEIGHT = 6 };

	typedef uint8_t BIndex;

	struct BNode {
	BIndex length;
	Key keys[BMAX];
	union {
	BNode *children[BMAX];
	Value values[BMAX];

	enum { BMAX = 32, BMIN = BMAX / 2, BHEIGHT = 6 };

	struct BNode {
	uint32_t length;
	Key keys[BMAX];
	union {
	BNode *children[BMAX];
	Value values[BMAX];
	};
	};