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Constants (Pre-defined)

The following constants are pre-defined by the compiler, and are available in both Spin and Propeller Assembly.

Constants (Pre-defined in Spin and Propeller Assembly)

Constant

Definition

Value (Decimal)

Value (Hexadecimal)

Value (Binary)

TRUE

Logical true

-1

$FFFFFFFF

%11111111111111111111111111111111

FALSE

Logical false

0

$00000000

%00000000000000000000000000000000

POSX

Maximum positive integer

2,147,483,647

$7FFFFFFF

%01111111111111111111111111111111

NEGX

Maximum negative integer

-2,147,483,648

$80000000

%10000000000000000000000000000000

PI

Floating-point value for PI

≈ 3.141593

$40490FDB

%01000000010010010000111111011011

RCFAST

Internal fast oscillator

1

$00000001

%00000000000000000000000000000001

RCSLOW

Internal slow oscillator

2

$00000002

%00000000000000000000000000000010

XINPUT

External clock/oscillator

4

$00000004

%00000000000000000000000000000100

XTAL1

External low-speed crystal

8

$00000008

%00000000000000000000000000001000

XTAL2

External medium-speed crystal

16

$00000010

%00000000000000000000000000010000

XTAL3

External high-speed crystal

32

$00000020

%00000000000000000000000000100000

PLL1X

External frequency times 1

64

$00000040

%00000000000000000000000001000000

PLL2X

External frequency times

128

$00000080

%00000000000000000000000010000000

PLL4X

External frequency times 4

256

$00000100

%00000000000000000000000100000000

PLL8X

External frequency times 8

512

$00000200

%00000000000000000000001000000000

PLL16X

External frequency times 16

1024

$00000400

%00000000000000000000010000000000

TRUE and FALSE

TRUE and FALSE are usually used for Boolean comparison purposes:

if (X = TRUE) or (Y = FALSE)
  <code to execute if total condition is true>

POSX and NEGX

POSX and NEGX are typically used for comparison purposes or as a flag for a specific event:

if Z > NEGX
  <code to execute if Z hasn't reached smallest negative>

—or—

PUB FindListItem(Item) : Index
  Index := NEGX                'Default to "not found" response
  <code to find Item in list>
  if <item found>
    Index := <items index>

PI

PI can be used for floating-point calculations, either floating-point constants or floating-point variable values using the FloatMath and FloatString object.

RCFAST through PLL16X

RCFAST through PLL16X are described in the Clock Mode Settings Constants table.

Note that they are enumerated constants and are not equivalent to the corresponding CLK register value.  See the CLK Register Table for information regarding how each constant relates to the CLK register bits.

Propeller Help Version 1.1

Copyright © Parallax Inc.

5/13/2009