Re: Looking for i860 Board and Developer Kit/Software
- From: jle@xxxxxxxxxxxxxxxxxxxx (Jason Lee Eckhardt)
- Date: Fri, 19 May 2006 21:03:42 +0000 (UTC)
In article <1147987002.249602.264630@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
<dereks314@xxxxxxxxx> wrote:
First off I have been trying to find out the difference between the
i860XP and i860XR processors. The couple of reference books I have
describe the instruction set and architecture but not the difference
between the two chips. Can sombody?
The i860XR was the first generation, and had a number of
shortcomings with respect to multi-processor support, trap
handling, performance, etc. The follow-on i860XP remedied
a number of the problems. Some of the differences are:
1. The XP increased the clock speed to 50MHz from 40MHz (max) for
the XR. (increasing peak MFLOPS to 100).
2. Icache/Dcache increased in size on XP to 16K/16K from 4K/8K.
3. The XP added new instructions: scyc.b, ldio.{b,s,l}, stio.{b,s,l},
ldint.{b,s,l}, and pfld.q (the XR only had pfld.d). See
the databooks for descriptions.
4. The XP added a number of control registers: ccr, p0-p3, and bear.
These are primarily for making trap handling easier than it was
on the XR (except for ccr).
5. The XP added a number of bits in the status word to make trap
handling and/or context switching a) easier, b) more efficient.
For example, the extra
bits made it much easier to determine the trap type. Perhaps
more importantly, there is a bit that helps determine whether
or not the FP pipelines must be saved. On the XR, one practically
always had to save/restore the FP pipes-- very expensive.
6. Etc.
Overall, the changes made the XP a better performer. From an
OS kernel hacker's perspective, it was easier to get the trap
handling right (fairly tricky on the XR).
If somebody has a i860 board and development environment that they are
interested in parting with, I'm very much in need for a little retro
project I'm working on.
Drop me a line, I'd be interested in hearing about your retro
project. I've done quite a few things related to the i860 in
the past, including gcc, a binutils port, a linux port, a partial
NetBSD port, a simulator, an LLVM port, compiler algorithms for
exploiting the manually-advanced pipelines, etc. With time,
I may resurrect some of these in the future. One of these days,
I may put up an i860 retrocomputing page.
I do have quite a bit of i860 equipment, but won't part with
any of it. I've also seen equipment for sale online in the past--
so it may not be too hard to find some old coprocessor boards
around. Try searching for MicroWay NumberSmasher/i860, for example.
Also search for Hauppauge 4860 (a combo i486/i860
motherboard), Transtech (they made some i860 coprocessor boards),
Alacron AL860 coprocessor board, etc. There were other coprocessor
boards in the early 1990's, though names now escape me.
Also, you may be able to find
an old NeXT workstation, some of which shipped with an i860-based
video card (IIRC).
Good luck.
.
- References:
- Looking for i860 Board and Developer Kit/Software
- From: dereks314
- Looking for i860 Board and Developer Kit/Software
- Prev by Date: Re: 64-bit Dual Core?
- Next by Date: MB mounting holes
- Previous by thread: Looking for i860 Board and Developer Kit/Software
- Next by thread: MB mounting holes
- Index(es):
Relevant Pages
|
