Path: utzoo!utgpu!attcan!uunet!mcvax!cernvax!hjm
From: hjm@cernvax.UUCP (Hubert Matthews)
Newsgroups: comp.arch
Subject: HW v. SW (was RISC v. CISC --more misconceptions)
Message-ID: <866@cernvax.UUCP>
Date: 3 Nov 88 08:46:22 GMT
References: <156@gloom.UUCP> <18931@apple.Apple.COM> <40@sopwith.UUCP> <998@l.cc.purdue.edu> <1622@scolex>
Reply-To: hjm@cernvax.UUCP (Hubert Matthews)
Organization: CERN European Laboratory for Particle Physics, CH-1211 Geneva, Switzerland
Lines: 12



The INMOS T800 has an instruction bitrevword, which turns a
little-endian word into a big-endian word, effectively doing a
reflection in the middle.  Great for FFT shuffle routines.  In
software, it takes quite some time.  In hardware it takes just over 
1 microsecond on a 30MHz part.  There is also a bitrevnbits which
reverses the bottom n bits in a byte and it takes n+4 cycles at 30MHz.
Again, not very quick in software.
-- 

	Hubert Matthews