Fixed Point Designer Reference

1174 Pages·4.182 MB·English

Fixed-Point Designer™
Reference
R2018b
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Fixed-Point Designer™ Reference
© COPYRIGHT 2013–2018 by The MathWorks, Inc.
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Revision History
March 2013 Online only New for Version 4.0 (R2013a)
September 2013 Online only Revised for Version 4.1 (R2013b)
March 2014 Online only Revised for Version 4.2 (R2014a)
October 2014 Online Only Revised for Version 4.3 (R2014b)
March 2015 Online Only Revised for Version 5.0 (R2015a)
September 2015 Online Only Revised for Version 5.1 (R2015b)
October 2015 Online only Rereleased for Version 5.0.1 (Release
2015aSP1)
March 2016 Online Only Revised for Version 5.2 (R2016a)
September 2016 Online only Revised for Version 5.3 (R2016b)
March 2017 Online only Revised for Version 5.4 (R2017a)
September 2017 Online only Revised for Version 6.0 (R2017b)
March 2018 Online only Revised for Version 6.1 (R2018a)
September 2018 Online only Revised for Version 6.2 (R2018b)

Contents
Apps — Alphabetical List
1
Property Reference
2
fi Object Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
bin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
dec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
double . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
fimath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
hex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
int . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
NumericType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
oct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
fipref Object Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
DataTypeOverride . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
DataTypeOverrideAppliesTo . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
FimathDisplay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
LoggingMode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
NumericTypeDisplay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
NumberDisplay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
quantizer Object Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
DataMode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
OverflowMode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
RoundingMode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
v
Fixed-Point Tool
3
Fixed-Point Tool Parameters and Dialog Box . . . . . . . . . . . . . . 3-2
Main Toolbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Model Hierarchy Pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Contents Pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Customizing the Contents Pane View . . . . . . . . . . . . . . . . . . . 3-8
Dialog Pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Fixed-Point Advisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Configure model settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
Run name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Simulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
Merge instrumentation results from multiple simulations . . . 3-15
Derive ranges for selected system . . . . . . . . . . . . . . . . . . . . 3-16
Propose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
Propose for . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Default fraction length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Default word length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
When proposing types use . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
Safety margin for simulation min/max (%) . . . . . . . . . . . . . . 3-18
Advanced Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
Advanced Settings Overview . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
Fixed-point instrumentation mode . . . . . . . . . . . . . . . . . . . . 3-20
Data type override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
Data type override applies to . . . . . . . . . . . . . . . . . . . . . . . . 3-23
Name of shortcut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25
Allow modification of fixed-point instrumentation settings . . . 3-25
Allow modification of data type override settings . . . . . . . . . 3-26
Allow modification of run name . . . . . . . . . . . . . . . . . . . . . . . 3-27
Run name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
Capture system settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
Fixed-point instrumentation mode . . . . . . . . . . . . . . . . . . . . 3-27
Data type override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28
Data type override applies to . . . . . . . . . . . . . . . . . . . . . . . . 3-29
vi Contents
Functions — Alphabetical List
4
Classes — Alphabetical List
5
Methods — Alphabetical List
6
Glossary

Selected Bibliography
A
vii

1
Apps — Alphabetical List
1
Apps — Alphabetical List
Fixed-Point Converter
Convert MATLAB code to fixed point
Description
The Fixed-Point Converter app converts floating-point MATLAB® code to fixed-point
MATLAB code.
Using the app, you can:
• Propose data types based on simulation range data, static range data, or both.
• Propose fraction lengths based on default word lengths or propose word lengths based
on default fraction lengths.
• Optimize whole numbers.
• Specify safety margins for simulation min/max data.
• View a histogram of bits used by each variable.
• Specify replacement functions or generate approximate functions for functions in the
original MATLAB algorithm that do not support fixed point.
• Test the numerical behavior of the fixed-point code. You can then compare its behavior
against the floating-point version of your algorithm using either the Simulation Data
Inspector or your own custom plotting functions.
If your end goal is to generate fixed-point C code, use the MATLAB Coder™ app instead.
See “Convert MATLAB Code to Fixed-Point C Code” (MATLAB Coder).
If your end goal is to generate HDL code, use the HDL Coder™ workflow advisor instead.
See “Floating-Point to Fixed-Point Conversion” (HDL Coder).
Open the Fixed-Point Converter App
• MATLAB Toolstrip: On the Apps tab, under Code Generation, click the app icon.
• MATLAB command prompt: Enter fixedPointConverter.
• To open an existing Fixed-Point Converter app project, either double-click the .prj
file or open the app and browse to the project file.
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