Specifications

BASIC Stamp II

Parallax, Inc. • BASIC Stamp Programming Manual 1.8 • Page 231

BS2 Runtime Math and Logic

The BS2, like any computer, excels at math and logic. However, being

designed for control applications, the BS2 does math a little differently

than a calculator or spreadsheet program. This section will help you

understand BS2 numbers, math, and logic.

Number Representations

In your programs, you may express a number in various ways, de-

pending on how the number will be used and what makes sense to

you. By default, the BS2 recognizes numbers like 0, 99 or 62145 as be-

ing in our everyday decimal (base-10) system. However, you may also

use hexadecimal (base-16; also called hex) or binary (base-2).

Since the symbols used in decimal, hex and binary numbers overlap

(e.g., 1 and 0 are used by all; 0 through 9 apply to both decimal and hex)

the Stamp software needs prefixes to tell the numbering systems apart:

99 Decimal (no prefix)

$1A6 Hex

%1101 Binary

The Stamp also automatically converts quoted text into ASCII codes,

and allows you to apply names (symbols) to constants from any of the

numbering systems. Examples:

letterA con "A" ' ASCII code for A (65).

cheers con 3

hex128 con $80

fewBits con %1101

For more information on constants, see the section BS2 Constants and

Compile-Time Expressions.

When is Runtime?

Not all of the math or logic operations in a BS2 program are solved by

the BS2. Operations that define constants are solved by the Stamp host

software before the program is downloaded to the BS2. This prepro-

cessing before the program is downloaded is referred to as “compile

time.” (See the section BS2 Constants and Compile-Time Expressions.)