16c 68 bit Index register???

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HP Forum Archive 11

16c 68 bit Index register???
Message #1 Posted by Steve on 13 Mar 2003, 1:00 p.m.

This is an open question on comp.sys.hp48, but I figured someone here would know. The 16c manual says that the Index register is always 68 bits regardless of the word size. Should it say 56 bits, or is there a reason for 68 bits? Thanks,
Steve

Re: 16c 68 bit Index register???
Message #2 Posted by Vieira, Luiz C. (Brazil) on 13 Mar 2003, 5:15 p.m.,
in response to message #1 by Steve

Hi;
it's been the subject of one thread a couple of months ago (begining of this year). It's a fact and there is no "know" way to access the four MSB's, unless you allow the calculator to count up over (2⁶⁴-1). This could be a test. Set 64 as WSIZE, store FFFF FFFF FFFF FFFF₁₆ in RI and write a program with ISZ GTO x, etc. and verify it it jumps to x in the next count. RI contets will return 0 but internaly it will be 1 0000 0000 0000 0000₁₆, so it should not jump until it passes through F FFFF FFFF FFFF FFFF₁₆ and back to 0 0000 0000 0000 0000₁₆, what gives us 2⁶⁸ - 2⁶⁴ cycles.
Wow! Is it correct? Gee...
Best regards.
Luiz C. Vieira - Brazil

Re: 16c 68 bit Index register???
Message #3 Posted by Jordi Hidalgo on 14 Mar 2003, 6:48 a.m.,
in response to message #2 by Vieira, Luiz C. (Brazil)

Luiz wrote:
> it's been the subject of one thread a couple of months ago
Wouldn't you love a way to search all the forum archives at once?
Jordi Hidalgo
HPCC #1046

I'm suspicious to talk about this...
Message #4 Posted by Vieira, Luiz C. (Brazil) on 14 Mar 2003, 9:21 a.m.,
in response to message #3 by Jordi Hidalgo

...because I offered myself to organize them in subjects and I tried, I swear I tried. I have already began, and I "talked" to Dave about this. He sent me all information I needed and I started at the moment I got the data. I had a 8MBytes text with almost all posts I found about Voyagers, having any mention, in all Forum database available at that time and I overwrote the file for a new, 80KBytes fresh, empty new text... I got to bed and tried not to think about it. I'm organizing them again, but my time is somewhat shorter for these days. I promisse I'll post news about this subject as they make any difference.
Thank you.
Luiz C. Vieira - Brazil

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