On Sat, Jul 18, 2015 at 2:51 PM, mm0fmf via Python-list
<python-list@python.org> wrote:
> On 18/07/2015 18:34, Mark Lawrence wrote:
>>
>>
>> What is an {HP calculator} roll operation?
>
>
> HP calculators were proper in that they used RPN entry.
>
> i.e. 2 enter 2 + would show 4 instead of 2 + 2 =
>
> Gawd it's so long but ISTR there were 3 stack registers and the display. So
> you could press
>
> 1 enter
> 2 enter
> 3 enter
> 4
>
> and Z = 1, Y = 2, X = 3 and display = 4. Roll would rotate the entries
> through the display register.
>
> ROLL and Z = 2, Y = 3, X = 4 and display = 1
>
> and so on. There was an INV ROLL to go the other way.
>
> The 3 level stack was equivalent to nesting parentheses three times. I only
> had a TI-59 as it was half the price of an HP67. The TI had more memories
> and program steps and was faster. But it didn't say HP on the front!
>
I have an hp35. But to be 'really' cool you have to have an hp35 that
just says hp. Those were the very first ones
--
Joel Goldstick
http://joelgoldstick.com
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