Comparing X with Indirect Y  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: Comparing X with Indirect Y (/thread80438.html) 
Comparing X with Indirect Y  James F. Chumbley  10262005 In the HP41CX Manual, Volume II, Page 305, under the topic "Comparisons," is given a list of six functions (X < NN?, X<=NN?, X=NN?, [X not= NN?], X>=NN?, X>NN?) which are said to compare the contents of the X register with the contents of the register whose name is contained in the Y register (Y Indirect). The part I don't understand is this statement of HP's: Place the address from 00 through 319 OR THE SINGLE LETTER X, Y, Z, T, OR L in the Y register. How do you put either an X, Y, Z, T or L into the Y register?
Thanks, Re: Comparing X with Indirect Y  donald wallace  10262005 Hi, You just put the letter in "alpha" register and execute an "ASTO Y". e.g. using Z into Y using decimal point as a stack operator signifier: [ALPHA]Z [ASTO][.]Y {command executes} [ALPHA] {leave ALPHA mode}
DW
Re: Comparing X with Indirect Y  James F. Chumbley  10262005 Thanks, Don, Re: Comparing X with Indirect Y  Geir Isene  10272005 Interestingly pointless to put "X" or "Y" in the Yregister...
Re: Comparing X with Indirect Y  donald wallace  10272005 Hi Jim, No worries. Anytime.
dw
Re: Comparing X with Indirect Y  donald wallace  10272005 Hi Geir, How are you doin'? x<>x is one way to get a time burning "noop". ;)
(used in the "old days" to check machine speed or burn up some time in a loop which didn't mess with data...)
Re: Comparing X with Indirect Y  Karl Schneider  10272005 Jim  Your question revealed to me an error in the 41CX Vol. II manual, as well as several insights about the functionality: Functionality:
Error:
 KS
Re: Comparing X with Indirect Y  Doug Wilder  10282005 Those missing relational functions can be had by use of another byte in program: for X>=0? one can use
X<=0? and for X>=Y?
X<=Y? Best
Edited: 28 Oct 2005, 3:36 a.m.
Synthesizing X>=0? and X>=Y?  Karl Schneider  10292005 Doug 
Quote:
During the same era, the HP10C and HP12C had only two of the twelve possible conditional tests; the HP34C, HP11C, and HP16C had eight; only the HP15C had all twelve. With GOTOdependent logic, it's a hassle to synthesize conditonal tests in this manner.
 KS
Re: Synthesizing X>=0? and X>=Y?  Doug Wilder  10312005 Hi Karl, I'm agreeing except i believe the problem was that the byte table was full! There are five lines for single byte functions, 80 of them, and no extras. Probably this is because the 41 has an Alpha register and needs a few slots to support it (CLA,PROMPT,AVIEW,AON,AOFF,ASHF). A couple of functions would have had to be left out, SDEV and MEAN possibly? I never use these yet the financial types around here would want E^X1 and LN1+X left out i suppose. There are a couple of spares (AF&B0) yet they are in the two byte area of the byte table (would make the mainframe flowchart look all weird).
Best
