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Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

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Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#12
"You might be surprised to learn that the calculator chip cannot perform multiplication natively. There's no floating point unit to multiply two numbers."

Quite true. The sexy multiplier chips from TRW (http://en.wikipedia.org/wiki/TRW_Inc. ) were still a few years off, and not intended for mere calculators. Same for the Intel x87 floating point co-processors (http://en.wikipedia.org/wiki/8087).

Nowadays the silicon real-estate cost for floating point math is trivial, and chip area is filled out with RAM cache for lack of anything better to do ...

Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#13
post #10

Reverse Polish Notation - sounds like the punch line to a really bad math joke

The joke has been going on for quite some time now - Lisp and related languages use Polish Notation everywhere.

(The main benefit is that (R)PN is parenthesis-free, so it makes it easier for a calculator to process expressions with multiple operators. The use in programming languages is nonexistent but to make clear that +, *, .. are just like any other function call, where you would naturally use polish notation.)

Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#15
post #10

Reverse Polish Notation - sounds like the punch line to a really bad math joke

After I got used to RPN (I had a lovely old HP-21) I found it much more intuitive. Stack-based thinking. No parentheses! (And I've used LISP for years, but that's entirely different.)

RPN vs Infix/Algebraic used to be a holy-war topic. Like emacs vs vi, or iPhone vs Android.

Once you go RPN, you can never go back again.

Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#16
post #10

Reverse Polish Notation - sounds like the punch line to a really bad math joke

The joke has been going on for quite some time now - Lisp and related languages use Polish Notation everywhere. (The main benefit is that (R)PN is parenthesis-free, so it makes it easier for a calculator to process expressions with multiple operators. The use in programming languages is nonexistent but to make clear that +, *, .. are just like any other function call, where you would naturally use polish notation.)

Not nonexistent-- there are many stack-oriented programming languages[1], of which Forth is the most famous.

There's even a "Reverse Polish Lisp" on HP calculators!

[1] http://en.wikipedia.org/wiki/List_of_programming_languages_b...

Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#17

Earlier quoted context omitted.

The joke has been going on for quite some time now - Lisp and related languages use Polish Notation everywhere. (The main benefit is that (R)PN is parenthesis-free, so it makes it easier for a calculator to process expressions with multiple operators. The use in programming languages is nonexistent but to make clear that +, *, .. are just like any other function call, where you would naturally use polish notation.)

Not nonexistent-- there are many stack-oriented programming languages[1], of which Forth is the most famous. There's even a "Reverse Polish Lisp" on HP calculators! [1] http://en.wikipedia.org/wiki/List_of_programming_languages_b...

Sorry, I meant there is no benefit to using it in programming languages.

Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#18

So is 'reversing' a common lazy shorthand for 'reverse engineering'? The title confused me until I realized what it was about. Feeling like an old fart...

Simple explanation - there wasn't room to fit "reverse engineering" into an 80-character title.

Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#19
post #10

Reverse Polish Notation - sounds like the punch line to a really bad math joke

The joke has been going on for quite some time now - Lisp and related languages use Polish Notation everywhere. (The main benefit is that (R)PN is parenthesis-free, so it makes it easier for a calculator to process expressions with multiple operators. The use in programming languages is nonexistent but to make clear that +, *, .. are just like any other function call, where you would naturally use polish notation.)

[deleted]

Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#20

  Unfortunately, as calculator prices collapsed, so did Sinclair Radionics' profits,
  and the company was broken up in 1979 after heavy losses.
He fought Moore's law, and the law won.

But this whole thing reminds me of Woz's work in the first Apples. Why wasn't his genius work similarly wiped out? Soon after the Apple, there were dozens - hundreds - of new personal computer manufacturers.

I think it's software. The value of a platform is what you can do with it. Software increases what you can do, therefore increases the value of the platform. There's increasing returns, so once it gets started, it gets harder and harder to stop.

Branding is also important (Jobs), which is why the Apple eventually fell to the "PC" - because the strongest computer brand in the world for decades was IBM.

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