Texas Instruments C28 Series User manual

Copyright © 2012 Texas Instruments Incorporated.FPU-DSP-LIB-UG-V131
USER’S GUIDE
C28x Floating Point Unit DSP Library

Copyright
Copyright © 2012 Texas Instruments Incorporated. All rights reserved. ControlSUITE is a registered trademark of Texas Instruments. Other names and
brands may be claimed as the property of others.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semicon-
ductor products and disclaimers thereto appears at the end of this document.
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Revision Information
This is version V131 of this document, last updated on Sep 10, 2012.
Sep 10, 2012 2

Table of Contents
Table of Contents
Copyright ..................................................... 2
Revision Information ............................................... 2
1 Introduction ................................................. 5
2 Library Structure .............................................. 6
2.1 Build Options used to build the library ................................... 7
2.2 Header Files ................................................. 7
2.3 A Note about C functions and IQMath ................................... 8
3 Function Descriptions ........................................... 9
3.1 Complex Fast Fourier Transform ...................................... 12
3.2 Complex Fast Fourier Transform (Unaligned) ............................... 15
3.3 Complex Fast Fourier Transform Magnitude ................................ 17
3.4 Complex Fast Fourier Transform Magnitude (Scaled) ........................... 19
3.5 Complex Fast Fourier Transform Phase .................................. 21
3.6 Complex Fast Fourier Transform Twiddle Factors ............................. 23
3.7 Inverse Complex Fast Fourier Transform ................................. 25
3.8 Real Fast Fourier Transform ........................................ 28
3.9 Real Fast Fourier Transform (Unaligned) ................................. 31
3.10 Real Fast Fourier Transform with ADC Input ............................... 33
3.11 Real Fast Fourier Transform with ADC Input (Unaligned) ........................ 36
3.12 Real Fast Fourier Transform Magnitude .................................. 38
3.13 Real Fast Fourier Transform Magnitude (Scaled) ............................. 40
3.14 Real Fast Fourier Transform Phase .................................... 42
3.15 Real Fast Fourier Transform Twiddle Factors ............................... 44
3.16 Finite Impulse Response Filter ....................................... 46
3.17 Absolute Value of a Complex Vector .................................... 50
3.18 Absolute Value of an Even Length Complex Vector ............................ 51
3.19 Addition (Element-Wise) of a Complex Scalar to a Complex Vector ................... 52
3.20 Addition of Two Complex Vectors ...................................... 53
3.21 Inverse Absolute Value of a Complex Vector ............................... 54
3.22 Inverse Absolute Value of an Even Length Complex Vector ....................... 55
3.23 Index of Maximum Value of an Even Length Real Array ......................... 56
3.24 Mean of Real and Imaginary Parts of a Complex Vector ......................... 57
3.25 Median of a Real Valued Array of Floats (Preserved Inputs) ....................... 58
3.26 Median of a real array of floats ....................................... 60
3.27 Complex Multiply of Two Floating Point Numbers ............................. 61
3.28 Complex Multiply of Two Complex Vectors ................................ 62
3.29 Multiplication of a Complex Vector and the Complex Conjugate of another Vector ........... 63
3.30 Multiplication of a Real scalar and a Real Vector ............................. 64
3.31 Multiplication of a Real Scalar, a Real Vector, and another Real Vector ................. 65
3.32 Multiplication of a Real Vector and a Complex Vector .......................... 66
3.33 Multiplication of a Real Vector and a Real Vector ............................. 67
3.34 Sort an Array of Floats ........................................... 68
3.35 Rounding (Unbiased) of a Floating Point Scalar ............................. 69
3.36 Subtraction of a Complex Scalar from a Complex Vector ......................... 70
3.37 Subtraction of a Complex Vector and another Complex Vector ..................... 71
3.38 Fast Square Root .............................................. 72
3.39 Optimized Memory Copy .......................................... 73
3.40 Optimized Memory Set ........................................... 74
Sep 10, 2012 3

Table of Contents
4 Revision History .............................................. 75
IMPORTANT NOTICE ............................................... 76
Sep 10, 2012 4

Introduction
1 Introduction
The Texas Instruments TMS320C28x Floating Point Unit (FPU) Library is collection of highly opti-
mized application functions written for the C28x+FPU. These functions enable C/C++ programmers
to take full advantage of the performance potential of the C28x+FPU. This document provides a
description of each function included within the library.
Sep 10, 2012 5

Library Structure
2 Library Structure
Build Options used to build the library ..................................................................... 7
Header Files ..............................................................................................7
ANote aboutCfunctions and IQMath ..................................................................... 8
As installed, the C28x FPU Library is partitioned into a well-defined directory structure. By default,
the library and source code is installed into the default controlSUITE directory,
C:\TI\controlSUITE\libs\dsp\FPU\VERSION
VERSION indicates the current revision of the FPU library. Figure. 2.1 shows the directory structure
while the subsequent table 2.1 provides a description for each folder.
Figure 2.1: Directory Structure of the FPU Library
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Library Structure
Folder Description
<base>Base install directory. By default this is
C:/TI/controlSUITE/libs/dsp/FPU/VERSION For the rest of
this document <base>will be omitted from the directory names
<base>/cmd Linker command files used in the examples
<base>/doc Documentation for the current revision of the library including re-
vision history
<base>/examples Examples that illustrate the library functions. At the time of writing
these examples were built for the F2833x device using CCS4 but
they can be imported into CCS5
<base>/include Header files for the FPU library. These include function proto-
types and structure definitions
<base>/lib Pre-built FPU libraries
<base>/source Source files and project for the library. Allows the user to recon-
figure, modify and re-build the library to suit their particular needs
<EXAMPLE>/matlab Matlab code for reference of debugging example project or lib
source code. FFT results in example projects can be compared
by the result in matlab code.
Table 2.1: FPU Library Directory Structure Description
2.1 Build Options used to build the library
The current version of the library was built with C28x Codegen Tools v6.0.1 with the following
options:
-v28 -mt -ml -g --diag_warning=225 --float_support=fpu32
2.2 Header Files
A library header file is supplied in the <base>/include folder. This file contains structure definitions
and function prototypes. The header file also includes the C28x data type definitions shown below:
#ifndef DSP28_DATA_TYPES
#define DSP28_DATA_TYPES
typedef int int16;
typedef long int32;
typedef long long int64;
typedef unsigned int Uint16;
typedef unsigned long Uint32;
typedef unsigned long long Uint64;
typedef float float32;
typedef long double float64;
#endif
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Library Structure
2.3 A Note about C functions and IQMath
Most of the functions contained in the C28x FPU library are c-callable assembly. A few functions
may be written in C. These C functions are written using the IQMath pre-processor notation. This
allows these functions to be easily ported from fixed point to floating-point math. The included
IQMath header file, IQmathLib.h, controls whether the code is built for fixed point or floating-point.
You may choose to configure the file IQmathLib.h in the controlSUITE directory to generate floating-
point code. i.e. the MATH_TYPE in the file is defined as FLOAT_MATH.
For more information on the IQMath notation, please refer to C28x IQMath Library - A Virtual
Floating Point Engine (SPRC087) which can be downloaded from TI’s website.
Sep 10, 2012 8

Function Descriptions
3 Function Descriptions
DSP Routines
ComplexFast Fourier Transform ..........................................................................12
ComplexFast Fourier Transform (Unaligned) .............................................................15
ComplexFast Fourier Transform Magnitude ..............................................................17
ComplexFast Fourier Transform Magnitude (Scaled) .....................................................19
Complex Fast Fourier Transform Phase .................................................................. 21
ComplexFast Fourier Transform TwiddleFactors .........................................................23
Inverse Complex Fast FourierTransform ..................................................................25
RealFast Fourier Transform ..............................................................................28
RealFast Fourier Transform(Unaligned) ................................................................. 31
RealFast Fourier Transformwith ADCInput ..............................................................33
Real Fast Fourier Transform with ADC Input (Unaligned) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
RealFast Fourier TransformMagnitude ...................................................................38
Real Fast Fourier Transform Magnitude (Scaled) ......................................................... 40
RealFast Fourier TransformPhase .......................................................................42
Real Fast Fourier Transform Twiddle Factors ............................................................. 44
Finite ImpulseResponse Filter ...........................................................................46
Vector and Matrix Routines
Absolute Valueof aComplexVector ......................................................................50
Absolute Valueof an Even Length Complex Vector .......................................................51
Addition (Element-Wise) of a Complex Scalar to a Complex Vector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Addition ofTwoComplex Vectors .........................................................................53
Inverse AbsoluteValue of a Complex Vector ..............................................................54
Inverse Absolute Value of an Even Length Complex Vector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Index of Maximum Valueof an Even Length Real Array ...................................................56
Meanof RealandImaginaryParts of a Complex Vector ..................................................57
Median of a Real Valued Array of Floats (Preserved Inputs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Median of a realarray of floats ...........................................................................60
ComplexMultiply of Two FloatingPoint Numbers .........................................................61
ComplexMultiply of Two Complex Vectors ................................................................62
Multiplication of a Complex Vector and the Complex Conjugate of another Vector . . . . . . . . . . . . . . . . . . . . . . . . . 63
Multiplication ofaReal scalar and a Real Vector ..........................................................64
Multiplication of a Real Scalar, a Real Vector, and another Real Vector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Multiplication ofaReal Vector and a ComplexVector .....................................................66
Multiplication ofaReal Vector and a RealVector .........................................................67
Sort an Array of Floats ...................................................................................68
Rounding (Unbiased) of a Floating Point Scalar .......................................................... 69
Subtraction of a Complex Scalar fromaComplex Vector ..................................................70
Subtraction of a Complex Vector and another Complex Vector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Math Routines
Fast Square Root ........................................................................................72
Utility Routines
Optimized Memory Copy .................................................................................73
Optimized Memory Set ...................................................................................74
Sep 10, 2012 9

Function Descriptions
The following functions are included in this release of the FPU Library. The source code for these
functions can be found in the source/C28x_FPU_LIB folder.
DSP
CFFT_f32 void CFFT_f32(CFFT_F32_STRUCT *);
CFFT_f32u void CFFT_f32u(CFFT_F32_STRUCT *);
CFFT_f32_mag void CFFT_f32_mag(CFFT_F32_STRUCT *);
CFFT_f32s_mag void CFFT_f32s_mag(CFFT_F32_STRUCT *);
CFFT_f32_phase void CFFT_f32_phase(CFFT_F32_STRUCT *);
CFFT_f32_sincostable void CFFT_f32_sincostable(CFFT_F32_STRUCT *);
ICFFT_f32 void ICFFT_f32(CFFT_F32_STRUCT *);
RFFT_f32 void RFFT_f32(RFFT_F32_STRUCT *);
RFFT_f32u void RFFT_f32u(RFFT_F32_STRUCT *);
RFFT_adc_f32 void RFFT_adc_f32(RFFT_ADC_F32_STRUCT *);
RFFT_adc_f32u void RFFT_adc_f32u(RFFT_ADC_F32_STRUCT *);
RFFT_f32_mag void RFFT_f32_mag(RFFT_F32_STRUCT *);
RFFT_f32s_mag void RFFT_f32s_mag(RFFT_F32_STRUCT *);
RFFT_f32_phase void RFFT_f32_phase(RFFT_F32_STRUCT *);
RFFT_f32_sincostable void RFFT_f32_sincostable(RFFT_F32_STRUCT *);
Filter
FIR_f32 void FIR_FP_calc(FIR_FP_handle);
Matrix and Vector
abs_SP_CV void abs_SP_CV(float32 *, const complex_float *, const Uint16);
abs_SP_CV_2 void abs_SP_CV_2(float32 *, const complex_float *, const
Uint16);
add_SP_CSxCV void add_SP_CSxCV(complex_float *, const complex_float *,
const complex_float, const Uint16);
add_SP_CVxCV void add_SP_CVxCV(complex_float *, const complex_float *,
const complex_float *, const Uint16);
iabs_SP_CV void iabs_SP_CV(float32 *, const complex_float *, const Uint16);
iabs_SP_CV_2 void iabs_SP_CV_2(float32 *, const complex_float *, const
Uint16);
maxidx_SP_RV_2 Uint16 maxidx_SP_RV_2(float32 *, Uint16);
mean_SP_CV_2 complex_float mean_SP_CV_2(const complex_float *, const
Uint16);
median_noreorder_SP_RV float32 median_noreorder_SP_RV(const float32 *, Uint16);
median_SP_RV float32 median_SP_RV(float32 *, Uint16);
mpy_SP_CSxCS complex_float mpy_SP_CSxCS(complex_float, complex_float);
mpy_SP_CVxCV void mpy_SP_CVxCV(complex_float *, const complex_float *,
const complex_float *, const Uint16);
mpy_SP_CVxCVC void mpy_SP_CVxCVC(complex_float *, const complex_float *,
const complex_float *, const Uint16);
mpy_SP_RSxRV_2 void mpy_SP_RSxRV_2(float32 *, const float32 *, const float32,
const Uint16);
mpy_SP_RSxRVxRV_2 void mpy_SP_RSxRVxRV_2(float32 *, const float32 *, const
float32 *, const float32, const Uint16);
mpy_SP_RVxCV void mpy_SP_RVxCV(complex_float *, const complex_float *,
const float32 *, const Uint16);
Continued on next page
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