test-drb March 2011

test-drb@ccmp.vtda.org

146 participants
225 discussions

hardware multiply/divide functionality in CPUs

by tshoppa＠wmata.com

>> [HP PA-RISC in 9000 840 done in TTL] > That's a useful one to know about! Was it a microcoded design, or was the > instruction decoding more logic-based? (which might explain the PALs!) I'm not enough of a PA-RISC conniseur to claim that there's nothing like microcode In there but... PA-RISC was a very consciously RISC effort. Shift-and-add instructions are part of the PA-RISC instruction set. Deragatory remarks from CISCy folks complained that PA-RISC instructions were in fact microcode :-). Some block diagrams are in the CE handbook at http://bitsavers.org/pdf/hp/9000_800/ According to openpa.net, they did a lot of good stuff with just 150 chips. I contrast with other minis of the 70's and early 80's which did much less with many more chips. From openpa.net: The TS-1 was the first PA-RISC production processor, introduced in 1986. It integrated version 1.0 of PA-RISC on six boards (each 8.4?11.3?) of TTL. Details: PA-RISC version 1.0 32-bit Three-stage pipeline The CPU consists of six separate boards: I-unit: the Instruction Unit Register File Board, contains general and control registers E-unit: the Execution Unit TLB, the translation lookaside buffer with 4096 entries for 2?KB pages Cache controller with split instruction and data caches ? 64?KB for each I and D FPC, the floating-point coprocessor, handles FP operations parallel to the CPU/ALU (the ADD/MUL/DIV chip was taken over from the HP 9000/550 FOCUS system) 4096-entry TLB off-chip, direct-mapped Off-chip L1 cache of 128?KB (I/D) direct-mapped/one-way associative Physical address space of 27-bit (128?MB main memory could be addressed) 8?MHz clock speed Six (some sources say five) printed circuit boards, implemented in FAST TTL and (25ns and 35ns) SRAMs/PALs, which each about 150 ICs Tim.

13 years, 2 months

hardware multiply/divide functionality in CPUs

by tshoppa＠wmata.com

> background: I'm revisiting a homebrew microcoded CPU that I started > thinking about a few years ago (with the intention of making it > predominantly from LS-TTL if I can get enough parts together). I hadn't > considered hardware multiply or divide before (the intention was just to > have library routines in software), but if it was relatively common on > systems between the mid-70s and early-80s then maybe I'll include > something. Simple shift-add multiply with unsigned integers is simple > enough, but I'm thinking that if I do it at all it'd be nice for it to work > with signed integers, too, so I've got some head-scratching to do :-) As to "common", if your CPU starts looking like a 68000 or 8086, then you'll probably have both signed and unsigned multiply and divide. (I think the original x86 had some instructions to assist with BCD multiply?) 68000 or 80x86 hardly seem like clever minimal instruction sets today... and for a long time those implementing CPU designs have tended towards RISC. e.g. PA-RISC was in production from 1986 through 2008, was a high performance micro, and had no hardware multiply. If you're looking for a good model for implementing in 74xx series logic, keep in mind that in 1986, HP was selling their new workstation, the HP 9000 840, which had its CPU largely implemented in 74F series logic (I think there were some PAL's etc. but my memory fades). IMHO unsigned multiply will usually be most appropriate for the bit twiddling a micro has to do. BUT... if you're gonna do Fortran benchmarks, you probably want signed multiply. (This is a sore point when it comes to implementing bit-twiddling multiplies in Fortran. Understandable because Fortran was designed around ones-complement processors.) Tim.

13 years, 2 months

Digital archiving tools

by tshoppa＠wmata.com

What you want, for goals #1 through #3, are simply disk and tape images, as commonly used with all the major simulators/emulators and tools. #4 and #5 are not part of the disk and tape images themselves, but you layer on top with checksums (Aka md5sum's) and geographically diverse storage networks etc. It's important not to confuse the image, with the media on which the image may currently be residing. A well-thought out image container format will outlast many generations of media. (And indeed have; RT-11 Logical Disk containers have existed since the 70's, and DECUS TPC-style tape images for nearly that long). This is why #1-#3 have to be decoupled from #4 and #5.

13 years, 2 months

hardware multiply/divide functionality in CPUs (6809)

by mtapley＠swri.edu

At 23:56 -0600 3/7/11, Jules wrote: >Yes, that seems to be the 'famous' one that gets mentioned everywhere. It >seems it was of the shift-add variety. Anyone recall if it would work with >signed integers? (I'm just trying to work out how the math works for signed >multiplies at the moment) I have a scanned .pdf of the 6809 programmer's manual here, happy to send out if anyone wants it, but it's 12.8 MBytes. (I got it >from the freescale website, since reorganized; it's online at http://www.maddes.net/m6809pm/ .) It says the MUL instruction A x B -> D (unsigned) takes 11 MPU cycles. ADD instructions take a minimum of 2 cycles, as do shift (roll, etc) instructions. So I think maybe there must have been some silicon (vs. microcode) involved in the multiply? I don't see how the shift-add sequence could be done in only 11 cycles. MUL is unsigned arithmetic only. -- - Mark 210-379-4635 ----------------------------------------------------------------------- Large Asteroids headed toward planets inhabited by beings that don't have technology adequate to stop them: Think of it as Evolution in Fast-Forward.

13 years, 2 months

need Radio Electronics from 1980

by chrism3667＠yahoo.com

not sure if the Unicorn-1 robot series went beyond 1980. I need all of them regardless.

13 years, 2 months

Lorlin Impact Test System Disk...

by lbickley＠bickleywest.com

I recently picked up a RL02 pack from a recycler. After doing my usual tear-down and clean process, I tested the pack on my 11/34C. It was 100% error free - and was initialized for RT-11. It is the system pack for a "Lorlin Impact Test System", Software Version 1.0M. It contains the IMPACT drivers (IMPACT.SYS) and the IMPACT main program (IMPACT.SAV). I do not have any Lorlin Impact hardware - so I plan to wipe the pack clean and use it for other purposes. However, before doing so, I wanted to pass it by this list - in case someone has a PDP-11 based Lorlin Impact system - and doesn't have this software. If you need this pack (or a copy of just the Lorlin Software), please contact me off list. Regards, Lyle -- Lyle Bickley, AF6WS Bickley Consulting West Inc. http://bickleywest.com "Black holes are where God is dividing by zero"

13 years, 2 months

New to the List -- Criteria for Being Salvageable? -- Query

by captainkirk359＠gmail.com

Hello fellow classic computer enthusiasts. I'm quite new to the list, but an avid fan of all things "retro" computerwise. Though, at present I don't have anything that could be described as a "classic" system beyond a KSR-33 teletype made by Leigh up here in Canada sometime during the 60s or 70s. Now, on to what the main thing I wanted to discuss... I'm a student at Brock University in southern Ontario, and I've noticed that the faculty of computer science has a small collection of quite vintage machines; from what I remember there's a "classic" PDP-8, a PDP-8/L and an HP2116 I think. They also have a nice ASR-33 teletype in the collection, as well as various other tidbits. So, my question is what would the criteria be to be able to make those systems capable of being run once more? From a cursory visual inspection, the PDP-8 appears to be complete, FLIP-CHIP wise, the PDP-8/L is enclosed but dusty, and I think the HP - which is open - has a pretty nice loadout of cards. So going by modules I would say all the hardware is there (save power supplies?), so what would be needed to bring up one of those systems? And more importantly, would any one be interested in signing (an online) petition to the BrockU CS Faculty to convince them to try and restore one of their minis and their terminal back into a functional state? And as a final query, I have no idea if this could be considered off topic or not, but are there any DEC enthusiasts in southern Ontario? (And any who are willing to part with a PDP-11 or OMNIBUS based PDP-8?) Cheers everyone, Christian Gauger-Cosgrove

13 years, 2 months

I Never Knew That The VT100 Was A Computer :-)

by robert.jarratt＠ntlworld.com

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=270716450383&ssPageName =ADME:B:SS:GB:1123 Regards Rob

13 years, 2 months

"300 Baud" magazine shuts down

by eric＠brouhaha.com

Issue #3 is unfortunately the final issue. You can now get PDF files of issues 1 through 3 from their web site: http://www.300baudmagazine.com/

13 years, 2 months

New to the List -- Criteria for Being Salvageable? -- Query

by dm561＠torfree.net

----- Original Message ----- > Date: Mon, 7 Mar 2011 21:33:09 -0500 > From: Christian Gauger-Cosgrove <captainkirk359 at gmail.com> > Subject: New to the List -- Criteria for Being Salvageable? -- Query > > ...And as a final query, I have no idea if this could be considered off > topic or not, but are there any DEC enthusiasts in southern Ontario? > (And any who are willing to part with a PDP-11 or OMNIBUS based > PDP-8?) > > Cheers everyone, > > Christian Gauger-Cosgrove ----- Reply: ----- Several on this list are in the GTA and Ottawa area that I know of, but I don't know what if anything they want to part with ;-)

13 years, 2 months

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test-drb March 2011