Propeller Manual

Introducing the Propeller Chip
Page 34 · Propeller Manual v1.1
can include schematics, timing diagrams and other diagrams right in the source code for your
application.
Log and Anti-Log Tables
The log and anti-log tables are useful for converting values between their number form and
exponent form.
When numbers are encoded into exponent form, simple math operations take on more
complex effects. For example ‘add’ and ‘subtract’ become ‘multiply’ and ‘divide.’ ‘Shift left’
becomes ‘square’ and ‘shift right’ becomes 'square-root.’ ‘Divide by 3’ will produce ‘cube
root.’ Once the exponent is converted back to a number, the result will be apparent.
See Appendix B: Math Samples and Function Tables on page 380 for more information.
Sine Table
The sine table provides 2,049 unsigned 16-bit sine samples spanning from 0° to 90°,
inclusively (0.0439° resolution). Sine values for all other quadrants covering > 90° to < 360°
can be calculated from simple transformations on this single-quadrant sine table. The sine
table can be used for calculations related to angular phenomena.
See Appendix B: Math Samples and Function Tables on page 380 for more information.
Boot Loader and Spin Interpreter
The last section in Main ROM contains the Propeller chip’s Boot Loader and Spin Interpreter
programs.
The Boot Loader is responsible for initializing the Propeller upon power-up/reset. When a
Boot Up procedure is started, the Boot Loader is loaded into Cog 0’s RAM and the cog
executes the code starting at location 0. The Boot Loader program first checks the host and
EEPROM communication pins for code/data to download/upload, processes that information
accordingly and finally it either launches the Spin Interpreter program into Cog 0’s RAM
(overwriting itself) to run the user’s Propeller Application, or it puts the Propeller into
shutdown mode. See the Boot Up Procedure section on page 18.
The Spin Interpreter program fetches and executes the Propeller Application from Main
RAM. This may lead to launching additional cogs to run more Spin code or Propeller
Assembly code, as is requested by the application. See Run-Time Procedure, page 18.