Using Numbers

Enter a number by typing its value, for example, 55 or -123. Forth accepts only integers (whole numbers); it does not understand fractional values (e.g., 2/3). A period at the end of a number signifies a double number. Periods or commas embedded in a number are ignored, so 5.77 is understood as 577. By convention, such punctuation usually appears every four digits. Use one or more spaces to separate a number from a word or from another number.

Unless otherwise specified, OpenBoot performs integer arithmetic on data items that are one cell in size, and creates results that are one cell in size.

Although OpenBoot implementations are encouraged to use base 16 (hexadecimal) by default, they are not required to do so. Consequently, you must establish a specific number base if your code depends on a given base for proper operation. You can change the number base with the commands decimal and hex to cause all subsequent numeric input and output to be performed in base 10 or 16, respectively.

For example, to operate in decimal, type:

ok decimal 
ok 

To change to hexadecimal, type:

ok hex
ok 

To identify the current number base, you can use:

ok 10 .d
16
ok 

The 16 on the display shows that you are operating in hexadecimal. If 10 showed on the display, it would mean that you are in decimal base. The .d command displays a number in base 10, regardless of the current number base.