HP 41 CPU speed



#6

Does anyone know what speed (Hertz) the original HP-41 CPU ran at?

vic


#7

The buses ran at about 355KHz, but each machine cycle was 56 clock pulses long; the machine would execute about 6300 machine instructions per second. Needless to say, it would take several machine instructions to implement each of the various HP41 functions that you could write user programs in.

The calculator had just 12K of 10bit words worth of ROM (20K for the HP41CX, since it included the x-functions and the time modules).

Amazing, no?

/ji


#8

John wrote:

"The buses ran at about 355KHz, but each machine cycle
was 56 clock pulses long; the machine would execute
about 6300 machine instructions per second. [ ... ]
The calculator had just 12K of 10bit words worth of ROM
Amazing, no?"


Yes. However, not being a hardware man, I find it
curious that the HP-71B had just twice as fast a clock
(about 600 Khz, if I'm not wrong), yet it was much more
than twice as fast as the 41C, up to 14 times or more.

I guess the reason is that each 71B's machine cycle
was much shorter than 56 clock pulses long ? Or was it
because of an improved architecture, or a combination
of other facts ?

Another fact I find curious is that the 41C could
execute some 6300 machine instructions per second. But
it could compute quite complicated trascendental
functions such as e^x or tan(x) in well under a second,
so I guess this means it had to execute significantly
less than 6300 machine operations to compute them ?
Hats off tehn to the algorithm designers and coders !


#9

> Hats off to the algorithm designers and coders!

Absolutely my opinion too. I had a closer look to the firmware when I did an emulator of the HP-41. That is the reason for the leitmotiv of my homepage: "Wer einen anderen nachahmt, erkennt dessen Überlegenheit an."
Ralph Boller (a swiss author)
About: Who imitates someone else appreciates his superiority.

See: http://ourworld.compuserve.com/homepages/nutem/

Ciao.....Mike


#10

A related idea I've always heard put this way (in the USA):

Imitation is the sincerest form of flattery.


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