Released 8th July, 2003. This is an upgrade to the L1540
Library which also incorporates string handling.
You need this if you're a serious programmer!!
Note: The included documentation is good but
terse. I will be providing more detailed documentation when I have
time. Check back later.
L1542 is a 33KB SysRPL library for the HP39/40. When you download it to your calculator this library gives
access to an add-on collection of extra functions which then
become available in HOME, in programs or in the CAS (on an HP40G). The
functions essentially comprise much of what makes the difference between an
HP40 and an HP49, plus some more.
Functions added include a decimal/hex conversions, a calendar,
a list of metric/imperial conversions, a list of physical
constants, some time/value/money functions similar to those on the
TI89, probability functions, vector plot and matrix slope plot,
multidimensional optimisation, discrete Fourier transforms and
numerical solution of differential equations. Even a help
command is included which explains how to use each function!
For programmers there are REALLY useful functions that let you
do bit manipulations, perform graphic plots, call programs in
nifty ways as functions (ie. returning values), use local variables
instead of the global ones A..Z and, most importantly, input,
manipulate and output string variables. String constants can also be realized with
the aid of an additional tiny library L1840, which is included in this
package.

This library even has a command to delete itself so that you
don't have to reset your calculator (losing not only the library
but everything else as well).
The source is included and compiles with the HP DOS tools.
Author: Martin Lang (Germany), with contributions from Jordi
Hidalgo.