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C28x IQmath Library
A Virtual Floating Point Engine
V1.5
July 8, 2008
Module user’s Guide
C28x Foundation Software
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Copyright 2002, Texas Instruments Incorporated
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Trademarks
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Acronyms
C28x+FPU: Refers to devices with the C28x plus floating-point-unit.
IQmath: High Accuracy Mathematical Functions (32-bit implementation).
QMATH: Fixed Point Mathematical computation
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Chapter 1. Introduction ................................................................................................ 6
1.1. Introduction..................................................................................................................... 6
Chapter 2. Installing the IQmath Library.................................................................... 7
2.1. IQmath Package Contents ............................................................................................. 7
2.2. How to Install the IQmath Library............................................................................... 8
Chapter 3. Using the IQmath Library.......................................................................... 9
3.1. IQmath Arguments and Data Types ............................................................................. 9
3.2. IQmath Data type: Range & Resolution..................................................................... 10
3.3. Calling an IQmath Function from C........................................................................... 11
3.4. Calling an IQmath function from C++ ....................................................................... 11
3.5. IQmath Section and Lookup Tables............................................................................ 12
3.6. IQmath Naming Conventions ...................................................................................... 15
3.7. Selecting the GLOBAL_Q format............................................................................... 16
3.8. Using the IQmath GEL file for Debugging................................................................. 17
3.9. Converting an IQmath Application to Floating-Point............................................... 19
3.10. The IQmath C-Calling Convention ......................................................................... 19
Chapter 4. Libraries Available.................................................................................... 20
Chapter 5. Function Summary................................................................................... 21
5.1. Arguments and Conventions Used .............................................................................. 21
5.2. IQmath Function Overview ......................................................................................... 22
Format conversion Utilities.............................................................................................. 22
Arithmetic Operations ..................................................................................................... 22
Trigonometric Functions: ................................................................................................ 23
Mathematical Functions: ................................................................................................. 23
Miscellaneous ................................................................................................................. 23
5.3. C28x IQmath Library Benchmarks ............................................................................ 24
Chapter 6. Function Descriptions .............................................................................. 26
6.1. Conversion Utilities....................................................................................................... 26
IQN.................................................................................................................................. 26
IQNtoF............................................................................................................................. 28
atoIQN............................................................................................................................. 29
IQNtoa............................................................................................................................. 30
IQNint .............................................................................................................................. 32
IQNfrac............................................................................................................................ 33
IQtoIQN ........................................................................................................................... 34
IQNtoIQ ........................................................................................................................... 35
IQtoQN ............................................................................................................................ 36
QNtoIQ ............................................................................................................................ 37
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6.2. Arithmetic Operations.................................................................................................. 38
IQNmpy........................................................................................................................... 38
IQNrmpy.......................................................................................................................... 39
IQNrsmpy........................................................................................................................ 40
IQNmpyI32...................................................................................................................... 41
IQNmpyIQX..................................................................................................................... 44
IQNdiv ............................................................................................................................. 45
6.3. Trigonometric Functions.............................................................................................. 48
IQNasin ........................................................................................................................... 48
IQNsin ............................................................................................................................. 49
IQNsinPU ........................................................................................................................ 51
IQNacos .......................................................................................................................... 53
IQNcos ............................................................................................................................ 54
IQNcosPU ....................................................................................................................... 56
IQNatan2......................................................................................................................... 58
IQNatan2PU.................................................................................................................... 60
IQNatan........................................................................................................................... 62
6.4. Mathematical Utilities .................................................................................................. 63
IQNexp ............................................................................................................................ 63
IQNsqrt............................................................................................................................ 64
IQNisqrt ........................................................................................................................... 66
IQNmag........................................................................................................................... 69
6.5. Miscellaneous Utilities .................................................................................................. 70
IQNabs ............................................................................................................................ 70
IQsat................................................................................................................................ 71
Chapter 7. Revision History........................................................................................ 72
