On Sunday, January 15, 2012 08:55:19 PM Kent A. Reed did opine: > On 1/15/2012 2:48 PM, gene heskett wrote: > > But I cut my computer teeth on an RCA 1802 without an assembler, I > > looked > > Gene: > > I think I had more genuine fun with the 1802 than with any other > microchip I've ever used. I still have one somewhere in my > last-in-never-out stack. > I have to agree. What looks to be an unusual architecture turns out to have only one real bottleneck, every internal register in it, 16 ea 16 bit wide registers, any one of which can be designated as program counter or data pointer in a single instruction once they had been initialized by loading the value from memory, 8 bits at a time into the accumulator, and them moving that data to the high or low byte of the target register was a PITA. But once they were loaded, it (figuratively speaking for an 1802 which needed 8 clock cycles for a machine cycle, and ran at .889 Mhz) flew right along. Since that particular application was synched to house vertical synch, and had to check & do lots of machine control stuff and feed the data to the video using dma, it blew me away when I put a flag in I could watch on a scope, that was cleared on the rising edge of vertical synch (its end at the end of line 9 of each field) and set when it was done and had reset itself to wait for the falling edge of the next pulse, and found it was all done, and was sitting there spinning its wheels by the middle of line 21 of each vertical field, 12 tv lines of 63.333333 u-secs each to do the whole loop. Obviously I was very impressed at the time.
> As for working without an assembler, when pushed by circumstances I used > to be able to program our DEC PDP8 and PDP11, and Data General Nova > minicouputers using just the front switch register and memory. I never quite had to get that close to the heart of things. We did have a PDP-11-7/23a at one time that I called a crashomatic, but IIRC that story is already embedded in the lists archives. DEC replaced every piece of that thing but the frame rail the serial number was on without effecting its need to crash several times a day. > What a joke. I can now write and execute a complex program on a PC in > about the time that it took me to enter the bootstrap loader for the > punched papertape reader (but only if you don't count the time it takes > first to boot up the PC). :-) > The ability to program from the switch register is right up there with > being able to field-fix a Teletype machine in terms of life-time > achievement (and I have a ton of other hugely important yet ultimately > irrelevant skills I could mention). And yet the experience in having done those things is priceless. > You know you have a problem when you first have to explain what the > "thing" was before you can explain why what you did with the "thing" was > so cool and still you get a blank look. I've been in similar straights quite a few times when trying to justify buying what I need to folks who can only judge it on "will it make us money". I have had a few GM's that were clairvoyant, but far more that never grasped the concept of an intelligent gamble. I, because of them, have developed an rather intense disregard for today's crop of MBA's, some of which I could have used for target practice with no remorse. > On a different subject, I like Andy Pugh's use of Octave (in a later > message). It's a great tool. >From the fairly well organized docs I'd have to agree. Now its up to me to learn how to use such a tool. > Regards. > Kent And the missus is? Cheers Kent, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> The founding fathers tried to set up a judicial system where the accused received a fair trial, not a system to insure an acquittal on technicalities. ------------------------------------------------------------------------------ RSA(R) Conference 2012 Mar 27 - Feb 2 Save $400 by Jan. 27 Register now! http://p.sf.net/sfu/rsa-sfdev2dev2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
