Approximate pi to 24 digits via keyboard

[rprosperi]

(02-02-2015 11:01 PM)Han Wrote:  Wait... the entire HP 71B ROM source code is available? Did I understand this correctly?

The HP-71B is by far the most thoroughly documented calculator/computer HP (or maybe any Mfr) ever made. In addition to the full source listing, there are 2 other volumes dedicated to the s/w architecture and APIs, system buffers, storage formats etc. plus there are 3 more volumes for the h/w, 2 more volumes for HP-IL and another Volume for the Forth/Assembler ROM.

After seeing all the interest and 3rd party activity with the 41, HP wanted to provide all the "tools" to take the 71B (originally the HP-44 internally) to the next level. As the story goes though, 71B sales remained disappointing after that large investment, and the team never produced such thorough docs for a product again.

As you probably know, the 71 Forth ROM by BillW was the direct ancestor of RPL, and with the exception of Jim Donnelley's awesome "An Introduction to HP 48 System RPL and Assembly Language Programming" HP never really did extensive internals docs again.