Here are some of the routines that I wrote for my HP-35s calculator. I wrote them mostly for fun, but I also found them useful in practice. Anything more complex is probably better solved on a real computer, which nowadays might mean a phone if you want to keep it portable. But a HP calculator still has a superior interface and battery life, so I hope you find these routines useful. Also included is a quick reference card for the routines and more advanced built-in functions which can be printed and is dimensioned to fit into the calculator's pouch.
S — A routine for storing and restoring the stack. Used by other routines to avoid clobbering intermediate results.
V — Cross product of two vectors. Unlike the example in the
calculator's manual which requires that you enter the six vector
components into named variables, this routine works on HP-35s's
native vectors (i.e. the [] notation).
M — Matrix routines that, like V, work with the [] notation
for vectors, making data entry more comfortable.
T — Tabulate a function over the specified interval.
Q — Solve the quadratic equation.
C — Solve the cubic equation.
Each routine is in its own file named after the letter that labels the routine. The file starts with the code so that your text editor can provide meaningful line numbers. Each routine consists of subroutines that also have meaningful labels in the form of equation text. These "equations" are jumped over and never executed, so the value of flag 10 doesn't matter. They only aid the reader. Since they may be misinterpreted as instructions, they are labeled with their checksums.
After the code comes the description of the routine, how it's meant to be called and what the subroutines do. The "public" subroutines, i.e. those that are meant to be called by the user directly, have GTO statements at the begining of the main routine for easy access. For example, the M routine, which contains matrix operations, is organized such that you call M001 or M002 for storing a matrix, M003 recalls the stored matrix, M004 multiplies a matrix with a vector, and so on.
Use of named variables is mostly avoided, except for I and J of course. Unless too inconvenient, routines try to only use anonymous memory for storage and stack for input and output. Anonymous memory is organized into segments of ten addresses, each belonging to a letter labeling a particular routine. The first two digits of an address are the number of the routine's letter label. For example, routine S is assigned addresses from 190 to 199 (although only three are actually used). This scheme allocates memory for all possible labels, whether they are used or not, and leaves the first 10 and the last 530 addresses free. If a routine uses any other memory, it is documented.
Unless otherwise noted in a particular file, the following applies.
Copyright 2017-2018 Jure Varlec jure@varlec.si
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
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