Bad News for 33S: a bug shared with 35s Message #1 Posted by bill platt on 17 Mar 2012, 10:31 p.m.
Recall Paul Dale's HP 35S bug list:
[link:http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=735]
Item 14 concerns an anomalous equation editor result running inside a program. I just tested this on my recent 33S and found that it too has the same problem. This is not suprising considering that other bugs from the 33S also propagated to the 35S including the trig bug close to 90 degrees.
Here is item 14:
LBL A
156.25
STO X
208.333333334 ;There are eight 'threes' in there
STO R
1.77951304201
STO Q
-R*X/(X*Q-R) ;Should evaluate to roughly -467, and it does
-R*X/(X*Q-R) ;Should (still) evaluate to roughly -467, but
calculator outputs 31.323 instead!
RTN
This is REALLY freaking disappointing.
And BY THE WAY, it fails EVEN if you run it MANUALLY in the equation editor! Even without having two lines programmed identically. Go into equation editor, hit <ENTER> to evaluate the expression, and the first time through it pops the correct value onto the stack. Go back into the editor, press <ENTER> again and voilà--the wrong answer is in X!
FURTHER, in addition to what Paul tested, I found that variables Q and R have to be exactly as he shows, however X can be up or down one (1) in the last postion i.e. 156.24 and 156.26 also fail. 156.23 or lower, and 156.27 works fine. For those who really know something about BCD, or machine address space or etc, is this a clue? Remember when someone found that M$ Excel 2007 was a DUD and gave wildly wrong results with particular numbers? The of course sent out a patch...
I ran this on my 33S serial cna 02500940 and it failed as described. I'll test my old one later, too and edit this post.
Testing on both a 32sii and a 20s shows correct operation.
Edited: 17 Mar 2012, 11:12 p.m.
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