pervognsen

/*
transpose_ij (10000x5000): gmemops=0.23, min=0.436734, avg=0.455368, relerr=3.42%
transpose_ji (10000x5000): gmemops=0.28, min=0.356635, avg=0.363628, relerr=2.55%
transpose_ij_ij (10000x5000): gmemops=1.53, min=0.065207, avg=0.069465, relerr=6.07%
transpose_rec1 (10000x5000): gmemops=1.44, min=0.069258, avg=0.075378, relerr=8.96%
transpose_rec2 (10000x5000): gmemops=1.37, min=0.072819, avg=0.079644, relerr=8.77%

transpose_ij (100000x100): gmemops=1.70, min=0.011731, avg=0.014102, relerr=9.99%
transpose_ji (100000x100): gmemops=0.23, min=0.086909, avg=0.095706, relerr=3.37%
transpose_ij_ij (100000x100): gmemops=1.73, min=0.011543, avg=0.013170, relerr=6.96%

pervognsen

; https://web.archive.org/web/20190701203222/https://www.pcengines.ch/tp3.htm
; The disassembler was applied to a copy of TP 3.01A downloaded from WinWorld.
; I postprocessed the disassembly with a script to clean up spacing and column alignment.

; *** TURBO PASCAL version 3.01 A source code
; ***
; *** commented by Pascal Dornier
; *** all rights reserved
; "***
        cseg    $100                     ; "COM file...

pervognsen

;       Math48 Floating Point Package
;       Version 1.1 Revision 1
;       by Anders Hejlsberg
;       2532 Bytes

;HOPTABEL

        JP   FPADD
        JP   FPSUB
        JP   FPMUL

dvanhorn

#lang racket
(require redex)

;; Run to explore all of the gradual typings of the example
(define (main)
  (traces -> (term example)))

(define-term example
  (λ (x : ?)
    (λ (y : ?)

robrix

module FoldsAndUnfolds where

import Data.List -- for unfoldr

class Functor f => Recursive f t | t -> f where
  project :: t -> f t

  cata :: (f a -> a) -> t -> a
  cata alg = go where go = alg . fmap go . project

wilbowma

#lang racket

;; An introduction to procedure inlining following a simplification of GHC's
;; inliner from:
;; https://www.microsoft.com/en-us/research/wp-content/uploads/2002/07/inline.pdf
;;
;; This version is a simplification in that:
;; 1. It picks loop breakers naively
;; 2. It ONLY inlines procedures (not other bound expressions)
;; 3. All calls are direct, so it's not context sensitive (although the

pervognsen

# Here's a probably-not-new data structure I discovered after implementing weight-balanced trees with
# amortized subtree rebuilds (e.g. http://jeffe.cs.illinois.edu/teaching/algorithms/notes/10-scapegoat-splay.pdf)
# and realizing it was silly to turn a subtree into a sorted array with an in-order traversal only as an
# aid in constructing a balanced subtree in linear time. Why not replace the subtree by the sorted array and
# use binary search when hitting that leaf array? Then you'd defer any splitting of the array until inserts and
# deletes hit that leaf array. Only in hindsight did I realize this is similar to the rope data structure for strings.
# Unlike ropes, it's a key-value search tree for arbitrary ordered keys.
#
# The main attraction of this data structure is its simplicity (on par with a standard weight-balanced tree) and that it
# coalesces subtrees into contiguous arrays, which reduces memory overhead and boosts the performance of in-order traversals

pervognsen

void parse_expr(Value *dest);

Sym *parse_ident(void) {
    if (tok != TOK_IDENT) {
        error("Expected identifier");
    }
    Sym *ident = tok_sym;
    next();
    return ident;
}

henrytill

(** "Landin's Knot" - implements recursion by backpatching *)
let landins_knot f =
  let r = ref (fun x -> assert false) in
  let fixedpoint = f (fun x -> !r x) in
  r := fixedpoint;
  fixedpoint

let factorial =
  let g f x =
    if x = 0 then

marcan

#!/boot/bzImage

# Linux kernel userspace initialization code, translated to bash
# (Minus floppy disk handling, because seriously, it's 2017.)
# Not 100% accurate, but gives you a good idea of how kernel init works
# GPLv2, Copyright 2017 Hector Martin <marcan@marcan.st>
# Based on Linux 4.10-rc2.

# Note: pretend chroot is a builtin and affects the current process
# Note: kernel actually uses major/minor device numbers instead of device name