MyRPL 1.0

MyTinycalc is a calculator with a built in language (MyRPL).

The language has both: a subset of the HP48 programming language and
a subset of the HP41 programming language.

My tinycalc will be only one of the future calculators capable of running MyRPL

The calculator has an dynamic n level stack and has HP41 commands as:

LBL nn
GTO nn
XEQ nn
X=Y? X#Y?
X>Y? X=Y? X<=Y?
X=0? X#0?
X>0? X<0?
X>=0? X<=0?

also, mytiny calc has lists up to 254 characters
with commands present in the HP48:

SIZE ( number of elements )
EVAL  (Returns the last element of a list)
LISTCH : Number of characters in the list ( No present in the 48)

Tiny calc has variables with commands for saving ,
loading and evaluating them:


The variables can save numbers , lists, characters o programs.

There is a main program as in the 41. (Note: In the 48 does not exist.)
Also, there is a main memory with numbered registers.

Setting the number of registers of main memory:

Set the number of registers to 100:


Ask for memory size:


The buttons [SIZE?] and [MSIZE] are located at MEMORY page.

In order to save or recall a  memory  the register number
goes before a STO or RCL

Example: 4 RCL  recalls memory 4
10  5  STO saves 10 in memory 5.
10 'B' STO saves 10 in variable B.

Indirect. (IND) Can be used with STO and RCL

10  5  IND STO
'B' IND RCL. If B contains 7, memory register 07 is recalled.
15 'C' IND STO . If C contains 3, 15 is saved to memory register 03

Has programming structures similar to the 48.
Also, there are conditionals of the HP48.

The stack is unlimited as in the 48.
There are many commands for stack management similar to 
commands present in the HP48.

The  program variables can invoke other program variables
up to 8 deep levels.

The main program can invoke program variables  
up to 9 levels.

The number of levels allowed with XEQ nn and RTN is 99

Programs either must be entered at hand in the program grid or loaded
from an external text file.

Programs can be saved in text format and later can be

Save the current program to a text file with name


Load the program :


Note: [LOAD] and [SAVE] are located in PROGRAM page.

A program can be written external to the calculator using a text

The width of each stack level is  254 characters max.

The max width of a program line is 79 characters.

Variables with special characters can be created in order to be
used only in the main program

Define the variable 'RCL 00' as 0 RCL:

'RCL 00'
<<0 RCL>>

Define the variable '++' as 1 +

<<1 +>>

Define the variable 'RCL IND 01' as ind 01 rcl:

'RCL IND 01'

In variables containing programs , due to the separator used is blank,
some of these tricks can not be used.

You can assign up to 18 keys.
At the beginning the 18 assignable keys are blank
Look at the calculator. The 18 assignable keys are in an arch around
the basic numeric keys.

To assign a key enter the key number ( 1 to 18 ), press enter,
then write the variable name, press enter , and press the assign button.

Assign variable A to key 1

To delete the assignment in key 1:

Note: [ASSIGN] is located in the BUTTONS page.

It is possible to export and import the variables and assigned keys

Save the current set of variables to a file named VARSTODAY.var


Load a set of variables from a file named LASTVARS.var

[LoadVars]  Located at MEMORY page

Save the current set of assigned buttons to a file named

[SAVE]  Located at BUTTONS page.

Load a set of assigned buttons from a file named

[LOAD]  Located at BUTTONS page.

To change the number of decimals  FIX is used


4 FIX   put the number of decimals to 4.

Naked (nude) internals.
Internal commands can be entered at the stack without delimiters
and later evaluated.


/     (Use /  located at the ALPHA page of the calculator! )

Then 4, 5 and / are located in the first three stack levels.
Now press [EVAL]

The same using a program:

<< / >>

So, if the program contains a single command and this command is
an internal command , you do not need the delimiters << and >>.


To stop a non responsive running program use F10 from your PC keyboard.