Samuel Chase samebchase

Foreward

This document was originally written several years ago. At the time I was working as an execution core verification engineer at Arm. The following points are coloured heavily by working in and around the execution cores of various processors. Apply a pinch of salt; points contain varying degrees of opinion.

It is still my opinion that RISC-V could be much better designed; though I will also say that if I was building a 32 or 64-bit CPU today I'd likely implement the architecture to benefit from the existing tooling.

Mostly based upon the RISC-V ISA spec v2.0. Some updates have been made for v2.2

Original Foreword: Some Opinion

The RISC-V ISA has pursued minimalism to a fault. There is a large emphasis on minimizing instruction count, normalizing encoding, etc. This pursuit of minimalism has resulted in false orthogonalities (such as reusing the same instruction for branches, calls and returns) and a requirement for superfluous instructions which impacts code density both in terms of size and

OpenBSD VMM howto

Setup

/etc/rc.conf.local

apmd_flags="-A"
dhcpd_flags=vether0
vmd_flags=
ntpd_flags="-s"

Basics

Precedence

There’s none: only evaluation from right to left. Although adverbs and conjunctions are applied first.

Global Variables

=: is like `setq’

gvar =. 23
fun1 =: 3 : 0
gvar + y

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

Please note that the article is now on my website, and even though I am still working on it, any feedback is appreciated. Thanks for reading !

On the Quest of recoding malloc(3)

Back when I did not know anything about programing and started to learn C, I was first introduced to pointers (and other dreaded horrors that made me curl into a corner and cry) and dynamic memory in general.

I was baffled, troubled, yet fascinated by the basic explanation on how memory worked, and started to dread the time where I would need to manually create my char arrays for each and every sentences of my program; right before learning about string literals and feeling like an idiot.

It was then where I was learning about memory allocation and came upon a function that I would call for long the "magic function" : malloc. Magic, because at that point I didn't know how it worked, let alone knew anything about memory other that it was a "chain of boxes for numbers".

	(require '[cemerick.url :as url]
	'[clojure.spec.alpha :as s]
	'[clojure.spec.gen.alpha :as gen]
	'[clojure.string :as string])

	(def non-empty-string-alphanumeric
	"Generator for non-empty alphanumeric strings"
	(gen/such-that #(not= "" %)
	(gen/string-alphanumeric)))

	# Assuming you're a regular user that has doas allowances for vmctl
	mkdir -p ~/vmm
	cd ~/vmm

	# Grab the the one of the virt iso's of Alpine Linux
	curl https://nl.alpinelinux.org/alpine/v3.6/releases/x86_64/alpine-virt-3.6.0-x86_64.iso -o alpine-virt-3.6.0-x86_64.iso

	# Make a new virtual disk image, change the size as needed
	vmctl create alpine-virt.img -s 6G


	(* Good morning everyone, I'm currently learning ocaml for one of my CS class and needed to implement
	an avl tree using ocaml. I thought that it would be interesting to go a step further and try
	to verify the balance property of the avl tree using the type system. Here's the resulting code
	annotated for people new to the ideas of type level programming :)
	*)

	(* the property we are going to try to verify is that at each node of our tree, the height difference between
	the left and the right sub-trees is at most of 1. *)

	// Parts from Ace; see <https://raw.githubusercontent.com/ajaxorg/ace/master/LICENSE>
	CodeMirror.defineMode("perl6", function(cmCfg, modeCfg) {

	// Fake define() function.
	var moduleHolder = Object.create(null);

	// Given a module path as a string, create the canonical version
	// (no leading ./, no ending .js).
	var canonicalPath = function(path) {
	return path.replace(/\.\//, '').replace(/\.js$/, '');

	;; project.clj
	;; [clj-time "0.6.0"]
	;; [org.clojure/data.json "0.2.4"]
	;; [clj-kafka "0.2.8-0.8.1.1"]

	;; Utility to find offsets in a given Kafka topic for a given
	;; cursor/point in time. The code assumes that each message has a
	;; monotonically increasing number (ex. unix timestamp) associated with
	;; it.