Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!pyramid!amdcad!mikep From: mikep@amdcad.AMD.COM (Mike Parker) Newsgroups: comp.arch Subject: Re: Today's dumb question... Message-ID: <20994@amdcad.AMD.COM> Date: 1 Apr 88 16:02:43 GMT References: <503@xios.XIOS.UUCP> <47649@sun.uucp> Reply-To: mikep@amdcad.UUCP (Mike Parker) Organization: Advanced Micro Devices Lines: 41 Keywords: SPARC, test_and_set, Am29000, floating-point In article webber@porthos.rutgers.edu (Bob Webber) writes: > >How does the 327 differ from the Am29027? The floating-point >instructions trapping on the Am29000 looked a bit odd to me. Is the >notion that it is important to standardize the interface to >floating-point stuff so that people can buy floating-point chips later >and not have to recompile? Yes. >Or is it that one would want to >``hardwire'' the coprocessor interactions that are currently being >done at trap when the chip space becomes available? > >--- BOB (webber@athos.rutgers.edu ; rutgers!athos.rutgers.edu!webber) > No comment, except that if one were to find the chip space and hardwire what are now traps wouldn't that relate back to the "not have to recompile" question. >[By the way, I have been pondering the SPARC and Am29000 chips for a >while now trying to figure out if it is plausible to build a simple >home computer around them. If any one has references that talk about >the sort of glue that holds together a board with such a processor, 1 >or 2 SCSI ports, 1 or 2 serial ports, and some static ram, I would >certainly be interested.] Oh, no. SRAM, too expensive for a PC. The Am29000 memory design handbook ought to be available real soon with a couple of inexpensive memory systems that still provide better performance than a Sun 4. (Given some SRAM to build a cache, the Am29000 averages twice the performance of the Sun 4, including floating-point with those "slow" traps). Talk to phil@amdcad.amd.com about his $1200 PC accelerator performance. mikep -- ------------------------------------------------------------------------- UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!mike ARPA: amdcad!mike@decwrl.dec.com