Hacker's Delight

If you're writing code in assembly or C or otherwise doing arithmetic where binary representation matters, this is the book you need.

This is an awesome book. Pure fun to see all the collected trickery and to make use of it.

Hey, this book is all about math on a CPU, and who doesn’t like that? I actually read this for the first time on the beach, and dip into it frequently. The second edition has a bunch of great additions. Buy this book. You won’t regret it! Unless maybe you don’t want to do arithmetic in your programs.

This is fun and useful assortment of low-level coding tricks/super-efficient algorithms. For instance, there are specialized algorithms for computing integer division-by-7. Who knows when this is useful, but if you need to do it super fast, use the algorithm in this book to shave off a bunch of cycles compared with floating-point division plus rounding. That's just a taste; there are explanations of super-optimized routines for popcount (counting the # of 1s in a binary word), all sorts of other binary operation tricks, stuff of grey codes, applications of Hilbert curves to binary codes, even exotic bases for number representations such as base -2 (negative 2) or even imaginary/complex bases (who knew these even existed?) Plenty more in here -- those are just some random fun topics. If these sound interesting, you need to read this book.

The value of this book is in it's shortcut for writing your own code for a microcontroller or generic processor. It contains many shortcuts that can be used at the machine code and c code level for general mathematics and bit detection and modification. There is a very good section on CRC mathematics and operations and error correction. However, a good knowledge of mathematical representation is desired since the book is not structured to make the information easy to understand. This would be a good book if you are trying to create complicated mathematical algorithms for a microprocessor or controller. I wouldn't recommend it for most programmers.

If this book doesn’t get you excited about writing code, nothing will.

When somebody asks me for a book recommendation that will make them cry, I always recommend this one.

This book is mind blowing. If you’ve ever gotten right down on the bare metal and need to move bits around, you may have seen a few of these ideas. For you kids who’ve never had to worry about a stray meg of memory or a GHz of CPU speed, all of this will seem completely foreign, yet intriguing if you’ve wondered what goes on when you really need things to move along smartly and you don’t have memory and clock to burn. This book is encyclopedic, and rewards reading in small doses. It’s full of clever math ideas and ways to use instructions more effectively than you’d normally expect.

Habe das Buch mit Freude (im Urlaub!) gelesen. Es geht etwas in die Mathematik, an die Hardware und sehr in die Informatik. Ein bisschen Formeln muss man mögen, ich habe aber nur an 2 oder 3 Stellen mal Papier und Bleistift benötigt, um die Ansätze nachzuvollziehen. Wer weiß, was passiert, wenn man eine Variable mit sich selbst mit XOR verknüpft, der fühlt sich hier wohl.

Essentiel à un projet numérique quant sur lequel je travaille. Vous y trouverez de belles astuces pour accélerer certains calculs bas niveau quand gagner quelques cycles supplémentaires est vital.

本文最初のプログラム（立っているビットのうち一番右のものを落とす）を見ただけでノックアウトされてしまいました。

This book is not one for the feint hearted. There is a lot of complex mathematical equations in the book. Its main focus is on algorithms woking with integer types to use the least amount of operations as possible. For small programs this sort of math may not be necessary, but once the program becomes large enough that a slow down is noticeable it will be good to build in better more efficient code. This sort of efficient code would be of benefit on mobile devices where there is not as much processing horsepower and less fast data access times. If you are already a proficient programmer looking for ways to speed your code up this is an excellent resource that will be worth looking at. This is not really aimed at a beginner programmer or someone with limited mathematic skills.

Great insight into CS in general.