2.1.1 On-Chip Boot ROM Math Tables
Approximately 4K of the boot ROM is reserved for floating-point and IQ math tables. These tables are provided
to help improve performance and save SARAM space.
The floating-point math tables included in the boot ROM are used by the Texas Instruments™
. The
C28x Fast RTS Library
is a collection of optimized floating-point math functions for C
programmers of the C28x with floating-point unit. Designers of computationally intensive real-time applications
can achieve execution speeds considerably faster than what are currently available without having to rewrite
existing code. The functions listed in the features section are specifically optimized for the C28x + FPU
controllers. The
Fast RTS Library
accesses the floating-point tables through the FPUmathTables memory
section. If you do not wish to load a copy of these tables into the device, use the boot ROM memory addresses
and label the section as “NOLOAD” as shown in
. This facilitates referencing the look-up tables
without actually loading the section to the target.
The following math tables are included in the Boot ROM:
•
Sine/Cosine Table, Single-precision Floating point
– Table size: 1282 words
– Contents: 32-bit floating-point samples for one and a quarter period sine wave
•
Normalized Arctan Table, Single-precision Floating point
– Table size: 388 words
– Contents 32-bit second order coefficients for line of best fit
•
Exp Coefficient Table, Single-precision Floating point
– Table size: 20 words
– Contents: 32-bit coefficients for calculating exp (X) using a Taylor series
Example 2-1. Linker Command File to Access FPU Tables
MEMORY
{
PAGE 0 :
...
FPUTABLES : origin = 0x3FD860, length = 0x0006A0
...
}
SECTIONS
{
...
FPUmathTables : > FPUTABLES, PAGE = 0, TYPE = NOLOAD,
...
}
The fixed-point math tables included in the boot ROM are used by the Texas Instruments™
- A Virtual Floating Point Engine
. The 28x IQmath Library is a collection of highly optimized and high precision
mathematical functions for C/C++ programmers to seamlessly port a floating-point algorithm into fixed-point code
on TMS320C28x devices.
These routines are typically used in computational-intensive real-time applications where optimal execution
speed and high accuracy is critical. By using these routines, you can achieve execution speeds that are
considerably faster than equivalent code written in standard ANSI C language. In addition, by providing ready-to-
use high precision functions, the TI IQmath Library can shorten significantly your DSP application development
time.
The IQmath library accesses the tables through the IQmathTables and the IQmathTablesRam linker sections.
The IQmathTables section is completely included in the boot ROM. From the IQmathTablesRam section, only the
IQexp table is included and the remainder must be loaded into the device if used. If you do not wish to load a
copy of these tables already included in the ROM into the device, use the boot ROM memory addresses and
Boot ROM
198
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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