HP Forum Archive 07

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HP 41 CPU speed Message #1 Posted by Vic on 5 Feb 2002, 3:15 p.m. Does anyone know what speed (Hertz) the original HP-41 CPU ran at? vic

Re: HP 41 CPU speed Message #2 Posted by John Ioannidis on 5 Feb 2002, 11:06 p.m., in response to message #1 by Vic 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

Re: HP 41 CPU speed Message #3 Posted by Ex-PPC member on 6 Feb 2002, 4:32 a.m., in response to message #2 by John Ioannidis 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 !

Re: HP 41 CPU speed Message #4 Posted by Mike (Stgt) on 6 Feb 2002, 7:22 a.m., in response to message #3 by Ex-PPC member > 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

Re: HP 41 CPU speed Message #5 Posted by Ellis Easley on 7 Feb 2002, 7:44 p.m., in response to message #4 by Mike (Stgt) A related idea I've always heard put this way (in the USA): Imitation is the sincerest form of flattery.

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