Service instructions

The following are miscellaneous functions, classed together in "service functions"

Clear register *
The specified register is cleared.
Example: D/*

The specified register is printed. To the extreme right, its name is printed too, together with the symbol.
 A Prints the value of A:

123.5    A

  Prints the value of M

3.1415926    M

 B/ Prints the value of B/ (the split registers are shown in lower case)

336.7389    b

 / Special case: advances the paper without printing


Start/Stop S
If the program is running, it is stopped. If it is stopped, it is run from the current position.
This allows the user to input data in the middle of a program, according to the following scheme:
1) The running program meets an S instruction, and stops.
2) The user can type a number, and when finished presses S again.
3) This time the S means "Start", the program starts form the position where it stopped and can retrieve the data input by the user, which will be found in register M.

The R S special instruction

This instruction exchanges registers R and D. Its use is intended mainly for programs that span over multiple cards. As registers D, E and F are overwritten when reading a card, one can save at least the contents of register D by temporarily putting it into R and then retrieving its contents after the new card has been read.

This page is part of the Programma 101 Web