|Re: Quiz: HP Voyagers! |
Message #4 Posted by Vieira, Luiz C. (Brazil) on 30 Aug 2005, 12:03 a.m.,
in response to message #3 by Howard Owen
I was leaving the University when I saw the quiz, so I just follow my memory. Yeap, no calculator in hands, no HoHPC site checking; I`m a teacher, cannot give a bad example, so, no cheating... I edited my first answer just because I forgot that the HP12C has [LN] and [e^x].
I took 'Conditional Tests' as described in the HP manuals. [F?] is named a 'flag test', and manuals do not exactly count it as conditional test, although I agree with you that it conditionally allows execution of (if flag set) or skips (if flag cleared) the instruction in the program step that follows it.
ISG and DSE (ISZ and DSZ in the HP16C) are mainly used as loop control instructions, and I also agree with you that there is a conditional test embeeded on both of them (four of them, if we count ISZ and DSZ inthe HP16C). Each of these instructions may be used as conditional tests, but as they perform three operations (change the register contents, tests the register contents in a very particular way, and perform or skips next program step), I think that they go beyond the single conditional test, probably the reason they are considered separately.
[B?] is a bit test instruction, and 'conditionally' skips or executes the next step if the flag (x-register) is set or cleared (in the binary number in y-register), respectively.
As the quiz was so precise mentioning the 12 conditional tests (found in the HP15C), the ten conditional test (also found in the HP11C and HP16C), I did not think twice. I agree with you, your answers are more precise when we consider the very instructions structure, and I must confess that if the figures were the ones you mention, I'd probably miss the answers.
Actually, I think I missed (I surely missed) the question about "no loop-counting", because I do not remember seeing such DSE or ISG in the HP10C. I do not even recall seeing the I register on it, neither the (i) indexer. In fact, thanks to a good soul (Hi, E.V.), I was able to complete my Voyager set some months ago with the addition of an HP10C to the other ones. I naver had an HP10C and actually could touch one and test it in the mid 80's.
Maybe I'm just justifying my answers and trying to earn my prize... <8^)
Thanks and best regards.
Luiz (yet with no calcs at hand, just counting on memory)
Edited: 30 Aug 2005, 12:09 a.m.