HP 35  links and references

"The boss wanted it!"
Made in USA...finally!
Hewlett Packard Logo

The best article on HP history (almost a book) that I have ever read!
John Minck's HP History
(updated version 29)

I quote John Minck:
Dave Cochran remembers, "Soon after that (the success of the HP 9100A), Hewlett began pestering me about putting the 9100 in his shirt pocket. Even several years later the right architecture for the state of IC miniaturization just wasn't there to accommodate what we wanted to do. I was even thinking of getting hold of Hewlett's tailor to get his pockets made bigger."

HP-35 in the
A mine of information and beautiful photos like the HP35 proto and the 4 versions side by side.

The Kenneth A. Kuhn's Online Museum and Technical History of Hewlett-Packard (and his cats !)
Professor Kenneth Kuhn has collected a huge inventory of HP vintage equipment : a great contribution to the history of the Hewlett-Packard Company!

Hpmemory : This beautiful new site (Marc Mislanghe) dedicated to HP history shows a huge collection of equipment and documents.
"The overall HP Memory Project is a work of gratitude from one of the many people
who had the good fortune to spend a full professional life working for one of the world's most successful High-Tech Companies , the Hewlett-Packard Co."

Looking for Hewlett Packard Manuals, Service Notes, Brochures, Data Sheets, References in the Hewlett Packard Catalog, Archives of the "The Hewlett Packard Journal" (from 1949 until 1998) ....
Go see visit the Glenn Robb's Vintage Hewlett Packard Archive.

Optical (and genial) dump of the ROM of HP-35
by Peter MONTA
Good old days, when things were not so small .... Peter kinda saw the 1's and the 0's!
I quote Peter:
"The ROMs were in TO-8 metal cans. I abraded off the top of the can with a Dremel tool, working all the way around the edge, kind of like a can opener."

Nonpareil high-fidelity simulator for calculators
by Eric Smith
First assembler and emulator for the Classic series calculator.
When I started my work on the HP 35 code, I used extensively CSIM -modified to my needs- to study the dynamic trace of calculation test cases.
I used my own methodology dubbed "predictive reverse engineering" : get a code (dump a ROM), build an emulator of this code, try to "predict" the behavior a the software in a different contexts, build "test cases" and check with the emulator, and so on in a loop. You are close to the goal when you're feeling "you think like" the designer.

Yet another HP-35 microcode level emulator but in JavaScript
by Ashley Nathan Feniello.

In his Blog ' Code Monkey Have Fun ' Ashley presents his little ROM image emulator, in JavaScript.
Have a look and have fun!
Ashley also scanned his HP-35 operating manual and put it on line HP35 Manual.
It was missing on this site!

"The Calculator" on WIKI
"In the first months orders were exceeding HP's expectations as to the entire market size."

"The Calculator" was "introduced" officially in January 1972 (source HP advertisements), but at the end of 1971 Dr. Barney Oliver (one of the fathers of the HP-35) paid a visit to the Jet Propulsion Laboratory (Caltech & NASA), Pasadena California and proudly pulled out of his jacket a brand new HP-35: "I just happen to have a little something here to show you" ...

Page 14 of the May 1972 edition of Scientific American, you could read that "Some things are changing for the better", "I must have read that ad hundreds of times while I waited for my HP 35 to come in the mail." wrote recently a friend.

At the end of spring 1972 (May), the June 1972 edition of HP Journal presented the "The 'Powerful Pocketful': an Electronic Calculator Challenges the Slide Rule" was given to press.
At the end of the article "Packaging the Pocket Calculator", there is an insert saying : "Note: At press time, orders for the HP-35 have exceeded expectations to such an extent that a waiting list has been established. Deliveries should Improve In the next few week".
5 months after the introduction, the success was in the pipeline.

"The HP 9825 story contains many, many firsts for the computer industry. But to understand why these firsts originated with the HP 9825, we must look back beyond the HP 9825’s year of introduction: 1976."

Don't miss on this beautiful site : "The HP 9100: The Initial Journey".
I quote Steve Leibson: "Cochran started out by analyzing algorithms in general and Volder’s CORDIC algorithms specifically. Macmillan explained Volder’s algorithms mostly by referring Cochran to Volder’s papers so Cochran flew down to Costa Mesa, California one day to talk directly to Volder. Volder explained his own algorithms and also pointed Cochran to other important algorithms including some pseudo multiplication and pseudo division algorithms published by J. E. Meggitt in the IBM Journal in 1962. Mostly, Cochran was on his own."

"The 'Powerful Pocketful': an Electronic Calculator Challenges the Slide Rule"
by Thomas M. Whitney, France Rode, and Chung C. Tung

(HP journal 06 1972)


Cordic links and references

J. E. Volder, "Binary Computation Algorithms for Coordinate Rotation and Function Generation," Convair Report, IAR-1 148, Aeroelectronics Group, June 1956.

Jack E. Volder, The CORDIC Trigonometric Computing Technique, IRE Transactions on Electronic Computers, September 1959

Jack E. Volder, "The Birth of CORDIC", Journal of VLSI Signal Processing 25, 101-105, 2000.

J. E. Meggitt, Pseudo Division and Pseudo Multiplication Processes, IBM Journal, April 1962.

S.F. Anderson, J.G. Earle, R.E. Goldschmidt, and D.M. Powers, "The IBM System/360 Model 91: Floating-Point Execution Unit," IBM J. Research and Development, vol. 11, pp. 34-53, Jan. 1967.

D. H. Daggett, "Decimal-Binary Conversion in CORDIC," IRE Transactions on electronic Computers, Vol. EC-8, No. 3, pp. 335-339, 1959.

M. A. Liccardo, "An Interconnect Processor with Emphasis on CORDIC Mode Operation," Masters Thesis EE Dept, University of California at Berkeley, September 1968.

J. S. Walther, "A unified algorithm for elementary functions," Proceedings AFIPS Spring Joint Computer Conference, pp. 379--385, 1971.

Tien Chi Chen, "Automatic Computation of Exponentials, Logarithms, Ratios, and Square Roots," IBM J. Res. Develop., 1972, pp.380-388.

D. S. Cochran, "Algorithms and Accuracy in the HP-35,"  Hewlett-Packard Journal, Vol. 23, No. 10, June 1972, pp. 10-11 http://www.hpl.hp.com/hpjournal/72jun/jun72a2.pdf

Vladimir Baykov, Problems of Elementary Functions Evaluation Based on Digit by Digit (CORDIC) Technique, PhD thesis, Leningrad State Univ. of Electrical Eng., 1972

Andraka, Ray, A survey of CORDIC algorithms for FPGA based computers.

J. S. Walther, "The story of unified CORDIC," The Journal of VLSI Signal Processing, Volume 25, Number 2, June 2000, pp. 107 - 112,
also in "The Best Computer Papers of 1971" p. 71, edited by O.R. Petrocelli, Auerbach, 1972.

CORDIC Bibliography Site


Special Thanks To Piotr Piatek
who did a constructive and painstaking reading of the most difficult pages of this site.
He helped me understand what was not clear in my text ! (my paper "digit by digit" method is a first
attempt to be more pedagogical). 
His research on the ROM of the ЭЛЕКТРОНИКА МК-85 (using a 16-bit PDP-11 compatible microprocessor ) demonstrated that the Meggitt's "digit by digit" algorithm was used, for the math routines, in this 1987 machine.

Special Thanks to Peter Monta who dumped and published the early HP-35 ROM with bugs (Feb 2006) and
kindly gave me a raw disassembly listing.
That was the trigger for my elucidation of the "famous bug"

Special Thanks to François Roulet (Ecole Polytechnique Fédérale de LAUSANNE) for his kind and cool support, the Lausanne way.

Good tools, good work

he forum of this site has been set up in a couple of hours using the beautiful "PunBB".
Thank you to Rickard Andersson.