© 2009–2011, Texas Instruments Incorporated
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1.1 On-Chip Boot ROM IQmath Tables
Approximately 4K of the boot ROM is reserved for floating-point and IQmath 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™ C28x FPU
Fast RTS Library (SPRC664
). 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
Example 1. This
facilitates referencing the look-up tables without actually loading the section to the target.
The following floating-point 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 1. Linker Command File to Access FPU Tables
The fixed-point math tables included in the boot ROM are used by the Texas Instruments™ C28x™
IQMath Library - A Virtual Floating Point Engine (SPRC087
). 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.
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 label the sections as “NOLOAD” as shown in Example 2 . This facilitates
referencing the look-up tables without actually loading the section to the target.
10
Delfino Boot ROM SPRUFN5B– March 2009 – Revised February 2011
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