More Info:16C 68bit I Register



#2

Based upon some testing, I believe that the I register does in fact have more than 64 bits. First, you need to set the complement mode to unsigned since it appears in 1 and 2 complement mode, if the high order bit is on, the sign is extended when the value is stored in I.

Using the following program steps:

LBL A
RCL I
PSE
ISZ
GTO A
R/S
LBL B
RCL I
PSE
DSZ
GTO B
R/S

Set the word size to 64. In the X enter FFFFFFFFFFFFFFF8, store X into I. Execute A (GSB A). You will see the values go to all F's, then 0, 1, 2, 3..., but the ISZ will not skip the GTO A, meaning the I is never 0 even though the 64bit wide X says it is. To prove it another way, with the "small" value still in X, do a GSB B. The values will decrement, 3, 2, 1, 0, FFFFFFFFFFFFFFFF, but the DSZ will not skip the GTO B.

Maybe something else is going on to cause this behavior, it's hard to tell. If only one of the 16C designers was around to ask, we would know for sure. Oh well!

Steve


Possibly Related Threads...
Thread Author Replies Views Last Post
  Bought a 16C to compensate a little Eelco Rouw 23 1,745 12-07-2013, 01:26 PM
Last Post: Eelco Rouw
  Shiny new 16C! Keith Midson 7 628 10-27-2013, 02:22 AM
Last Post: Keith Midson
  HP 50g info Jan 7 737 10-21-2013, 09:09 PM
Last Post: Mike Morrow
  Prime 'CONTENT' section not retaining info text Geoff Quickfall 2 386 10-17-2013, 05:24 PM
Last Post: Geoff Quickfall
  Little curiosity: why the fourth stack register is called "T"? Antlab 34 2,020 07-03-2013, 04:49 PM
Last Post: Walter B
  HP-16C simulator fhub 12 902 06-30-2013, 10:14 PM
Last Post: Robert Prosperi
  Prime Info DavidShenk 0 247 06-14-2013, 11:39 AM
Last Post: davidshenk
  Program for HP-16c... Leonid 9 748 06-07-2013, 08:51 PM
Last Post: David Hayden
  HP 11C/12C/15C/16C case Philippe Cairic 4 570 11-06-2012, 06:04 PM
Last Post: Matt Agajanian
  Understanding HP-16C integer division Jimi 18 1,237 10-16-2012, 09:13 PM
Last Post: Eddie W. Shore

Forum Jump: