Date: Wed, 21 Mar 2012 09:47:39 +0400 From: Solar Designer <solar@...nwall.com> To: john-dev@...ts.openwall.com Subject: left shift by 1 via ADD magnum - There are some rotates by 1 bit in SHA-1. When we don't have XOP, those involve left shifts by 1 bit (as well as right shifts and ORs). The left shifts may be replaced by ADDs, which are 1 byte shorter. (I am already using this trick in the DES key setup.) The attached patch reduces the sse-intrinsics.o .text size by 128 bytes here (relative to the version with MD5 optimizations). The reduced code size might result in a speedup on CPUs with caching of x86 instructions (as opposed to micro-ops) - on Atom maybe? On E5420, there's no difference. Alexander View attachment "sse-intrinsics.c-sha.diff" of type "text/plain" (890 bytes) View attachment "sse-intrinsics.c.diff" of type "text/plain" (876 bytes)
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.