Category Archives: string search

Bug fix for ACISM

Several people have used the Aho-Corasick interleaved state-transition matrix code, only to find it didn’t match all strings (!) The bug was in the machine construction: the “prune backlinks” step in acism_create is (as-is) broken. I commented it out, and … Continue reading

Posted in aho-corasick, algorithm, string search | Leave a comment

“Unusual uses of SSE2” posted to github

In this month’s frenzy of putting source code out there in a usable form, I’ve posted source to github for the SSE2 implementations of string search, BNDM search, sorting [16] doubles, and bit-matrix transpose; plus some convenience tools for SSE2. … Continue reading

Posted in bit, bit matrix transpose, bit shift, ffs, SSE2, string search, Uncategorized | 2 Comments

SSE2 beats SSE4.2 in memcmp?

At the moment I haven’t any box where I can test the latest GCC compilers and SSE4.2 support (pcmpestri etc). So far, the following beats gcc 4.4 with -march=corei7 -msse4.2 (okay, perhaps that’s redundant :-). But gcc generates “repz cmpsb” … Continue reading

Posted in ffs, SSE2, SSE4.2, string search | 2 Comments

SSE2 and BNDM string search

For the past few weeks, I’ve been testing and experimenting with the Railgun string search function written by Sanmayce. Railgun is really a “memmem” function, where the target length is known in advance; and the cost of compiling the pattern … Continue reading

Posted in algorithm, SSE2, string search | Tagged , , , , , , | 8 Comments