Articles or book(s) about the functions behind a scientific calculator

[Thomas Klemm]

Addendum:
A while ago I've written a Python to FOCAL Compiler.
The program is still online: just click run ▸ and define your function.

Code:

def example(x): 
    return x**2 + 1

And then run:

Code:

translate(example.__code__)

This will produce the following HP-41 program:

Code:

LBL "EXAMPLE"
STO 00 ; x
RDN
RCL 00 ; x
2
Y↑X
1
+
RTN

---

And then there's tcab's fancy Python to RPN - source code converter.

It will translate:

Code:

LBL("EXAMPLE")
x**2+1

to:

Code:

LBL "EXAMPLE"
RCL 00
X↑2
1
+
LBL 50
"-Utility Funcs-"
RTN

HTH
Thomas