Notes on computers, programming and all the stuff

Base64 decoding could also be vectorized, although the speedup is not very impressive, merely 35%. Read more ...

An SSE code is more than 2 times faster on Core i7, and around 70% faster on Core i5. Read more...

The problem: there is a ordered dictionary containing only unique keys. Dictionary is read only, and keys are 32-bit (SSE) or 64-bit (AVX2...

The problem: there are 64-bit values with some data bits and some metadata bits; metadata includes a k-bit field describing a "type...

Intel's version of SIMD offers following 2-argument ( binary ) boolean functions: and , or , xor , and not . There isn't a single ar...

AVX2 has added support for 256-bit arguments for many operations on packed integers, although not all. Some instructions accept the 256-bit ...

Informal specification: __m128i mask_lower(const unsigned n) { assert(n < 16); switch (n) { case 0: return {0x00, ...

Milo Yip has compared different itoa and dtoa implementations on Core i7, including my itoa algorithm 2 , that use SSE2 instructions. R...

Sounds crazy, but it's possible in some cases . Here are experiments results - 3 times faster isn't so bad. list ...

Conversion numbers to hexadecimal representation - SWAR, plain SSE, and draft of BMI2 implementation. Article SSSE3: printing hex values...

New article Conversion numbers to binary representation — SIMD & SWAR versions. Few years ago I've described an MMX variant of SI...

SSE instruction PMOVMSKB gathers all most significant bits from bytes and stores them as a single 16-bit value; similar action is performed...

Rabin-Karp algorithm uses a weak hash function to locate possible substring positions. This modification uses merely equality of first and...

Fast calculate ceil(log10(x)) of some unsigned number is described on Bit Twiddling Hacks , this text show the SIMD solution for 32-bit numb...

The description of Determine if a word has a zero byte from "Bit Twiddling Hacks" says about haszero(v) : " the result is th...

Intel announced new extension to SSE : instructions accelerating calculating hashes SHA-1 and SHA256. As everything else added recently to ...

Lockless Inc publish a lot of interesting, advanced articles . There are some low-level things, algorithms, threading, and many more. Defin...

Suppose we need to get mask when nonnegative argument is greater then some constant value; in other words, we want to evaluate following exp...