242 Part 3 The instruction-set processor level: variations in the processor
Section 4 Desk calculator computers: keyboard processors with small memories
data as null instructions so that both data (for reading and writing) and instructions can be stored in the same register.
Examples. A program to take values for the numbers A, B, C, and D from the keyboard and then print the value of the expression [(A + B) x C]/D would be written as follows:
1M is implied if left blank.
The following program computes and prints n!. n is entered from the keyboard, where n > 1 and an integer. The program is started by pressing key Z.
Many algorithms have been written for Programma 101, being coded in impressively small space. The techniques have sometimes been borrowed from conventional computer programming. For example, multiple card programs operate by using chains in the same way as large FORTRAN programs. The significant fact to the reader is that the Programma 101 calculator is a nicely designed stored program computer.