Real-Time Workshop Release Notes

New Features

This section introduces the new features and enhancements added in the Real-Time Workshop 4.1 since the Real-Time Workshop 4.0.

For information about Real-Time Workshop features that are incorporated from recent releases, see Release Summary.

Note    For information about closely related products that extend the Real-Time Workshop, see the Release Notes sections about the Real-Time Workshop Embedded Coder and xPC Target.

Block Reduction Option On by Default

The Block reduction option (on the Advanced page of the Simulation Parameters dialog box) is now turned on by default. In prior releases, this option was off by default.

Block reduction collapses certain groups of blocks into a single, more efficient block, or removes them entirely. This results in faster model execution during simulation and in generated code.

See Block Reduction Option in the Real-Time Workshop User's Guide for further information.

Buffer Reuse Code Generation Option

The Buffer reuse option is now available via the General Code Generation Options (cont.) category of the Real-Time Workshop page. When the Buffer reuse option is selected, signal storage is reused whenever possible.

In previous releases, this option was available only through MATLAB set_param and get_param commands, such as:

• set_param(gcs,'bufferreuse','on')
  

The set_param and get_param commands are still supported.

See Buffer Reuse Option and Signals: Storage, Optimization, and Interfacing in the Real-Time Workshop User's Guide for further information.

Build Directory Validation

The build process now disallows building programs in the MATLAB directory tree. If you attempt to generate code in the MATLAB directory tree, an error message will be displayed prompting you to change to a working directory that is not in the MATLAB directory tree. On a PC, you can continue to build in the directory matlabroot/Work.

The build process also prevents building programs when matlabroot has a dollar sign ($) in its MATLAB directory name.

Build Subsystem Enhancements

The Build Subsystem feature, introduced in Real-Time Workshop 4.0, lets you generate code and build an executable from any nonvirtual subsystem within a model. In Real-Time Workshop 4.1, the Build Subsystem feature has been enhanced as follows:

• The Build Subsystem window now displays additional information about block parameters referenced by the subsystem.
• From the Build Subsystem window, you can now inline any parameter or set the storage class of any parameter.

See Generating Code and Executables from Subsystems in the Real-Time Workshop User's Guide for further information.

C API for Parameter Tuning Documented

The Real-Time Workshop provides data structures and a C API that enable a running program to access model parameters without use of external mode. This API has now been fully documented.

To access model parameters via the C API, you generate a model-specific parameter mapping file, model_pt.c. This file contains parameter mapping arrays containing information required for parameter tuning.

See C API for Parameter Tuning in the Real-Time Workshop User's Guide for information on how to generate and use the parameter mapping file.

Code Readability Improvements

Improvements to the readability of generated code include:

• Elimination of redundant parentheses.
• Long C statements in the generated code are now split across multiple lines.
• Block comments are more informative.

Control Flow Blocks Support

Simulink 4.1 implements a number of blocks that support logic constructs such as if-else and switch, and looping constructs such as do-while, for, and while. The Real-Time Workshop 4.1 supports code generation from these blocks.

For further information on the flow control blocks, see Control Flow Statements in Using Simulink.

Expression Folding

Expression folding is a code optimization technique that minimizes the computation of intermediate results at block outputs, and the storage of such results in temporary buffers or variables. Wherever possible, the Real-Time Workshop collapses, or "folds," block computations into single expressions, instead of generating separate code statements and storage declarations for each block in the model.

Expression folding dramatically improves the efficiency of generated code, frequently achieving results that compare favorably to hand-optimized code. In many cases, model computations fold into a single highly optimized line of code.

Most Simulink blocks support expression folding.

For further information, see Expression Folding in the Real-Time Workshop User's Guide.

External Mode Enhancements

Inline Parameters Support

The Real-Time Workshop now lets you use the Inline parameters code generation option when building an external mode target program. When you inline parameters, you can use the Model Parameter Configuration dialog to remove individual parameters from inlining and declare them to be tunable. This allows you to improve overall efficiency by inlining most parameters, while at the same time retaining the flexibility of run-time tuning for selected parameters that are important to your application. In addition, the Model Parameter Configuration dialog offers you options for controlling how parameters are represented in the generated code.

Each time Simulink connects to a target program that was generated with Inline parameters on, the target program uploads the current value of its tunable parameters (if any) to the host. These values are assigned to the corresponding MATLAB workspace variables. This procedure ensures that the host and target are synchronized with respect to parameter values.

All targets that support external mode (i.e., grt, grt_malloc, and Tornado) now allow inline parameters.

See Overview of External Mode Communications in the Real-Time Workshop User's Guide for further information.

Status Bar Display

When Simulink is connected to a running external mode target program, the simulation time and other status bar information is now displayed and updated just as it would be in normal mode.

Generate Comments Option

This option lets you control whether or not comments are written in the generated code. See Generate Comments in the Real-Time Workshop User's Guide for further information.

Include System Hierarchy in Identifiers

When this option is on, the Real-Time Workshop inserts system identification tags in the generated code (in addition to tags included in comments). The tags help you to identify the nesting level, within your source model, of the block that generated a given line of code.

See Include System Hierarchy in Identifiers in the Real-Time Workshop User's Guide for further information.

Rapid Simulation Target Supports Inline Parameters

The Rapid Simulation Target now works with Inline parameters on. Note that when Inline parameters is on, the storage class for all parameters and signals is silently forced to auto.

S-Function Target Enhancements

The S-Function Target Generate S-function feature, introduced in Real-Time Workshop 4.0, lets you generate an S-function from a subsystem. This feature has been enhanced as follows:

• The Generate S-function window now displays additional information about block parameters referenced by the generating subsystem.
• If you have installed and licensed the Real-Time Workshop Embedded Coder, the Generate S-function window lets you invoke the Embedded Coder to generate an S-function wrapper.

See Automated S-Function Generation in the Real-Time Workshop User's Guide for details.

Storage Classes for Block States

For certain block types, the Real-Time Workshop lets you control how block states in your model are stored and represented in the generated code. Using the State Properties dialog, you can:

• Control whether or not states declared in generated code are interfaceable (visible) to externally written code. You can also specify that signals are to be stored in locations declared by externally written code.
• Assign symbolic names to block states in generated code.

For further information, see Block States: Storing and Interfacing in the Real-Time Workshop User's Guide.

Support for tilde (~) in Filenames on UNIX Platforms

All filename fields in Simulink now support the mapping of the tilde (~) character in filenames. For example, in a To File block you can specify <code>~/outdir/file.mat</code>. On most systems, this will expand to /home/$USER/outdir/file.mat. The Real-Time Workshop uses the expanded names.

Target Language Compiler 4.1

This section summarizes changes that have been made to the Target Language Compiler in this release. See also TLC Compatibility Issues.

New TLC Debugger

The TLC debugger helps you identify programming errors in your TLC code. The debugger lets you set breakpoints in your TLC code, execute TLC code line-by-line, examine and change variables, and perform many other useful operations.

The TLC debugger operates during code generation, incurring almost no overhead in the code generation process. You can invoke the debugger:

• By selecting options in the TLC debugging options category of the Real-Time Workshop page
• By including %breakpoint statements in your TLC file.
• By using the MATLAB tlc command, as in

• tlc -dc <options>
  

• By using the -dc build option in the System target file field of the Real-Time Workshop page.

For further information, see Debugging TLC in the Target Language Compiler Reference Guide.

model.rtw File Format Changes

The format of the model.rtw file has changed. See TLC Compatibility Issues.

Cleanup of Block I/O Connection Handling in TLC

The handling of signal connections in rtw/c/tlc/blkiolib.tlc and rtw/ada/tlc/blkiolib.tlc was reworked. See the discussion of LibBlockInputSignal in TLC Function Library Reference in the Target Language Compiler Reference Guide.

Literal String Support

If a string constant is prefixed by the L format specifier, then no escape character processing is performed on that string. This is useful for specifying PC style path or directory names, as in this example.

• %addincludepath L"C:\mytlc"
  

New TLC Library Functions

The following functions have been added to the TLC Function Library:

• LibBlockInputSignalConnected
• LibBlockInputSignalLocalSampleTimeIndex
• LibBlockInputSignalOffsetTime
• LibBlockInputSignalSampleTime
• LibBlockInputSignalSampleTimeIndex
• LibBlockOutputSignalOffsetTime
• LibBlockOutputSignalSampleTime
• LibBlockOutputSignalSampleTimeIndex
• LibBlockMatrixParameterBaseAddr
• LibBlockParameterBaseAddr
• LibBlockNonSampledZC

See TLC Function Library Reference in the Target Language Compiler Reference Guide for information on these functions.

TLC Bug Fixes

• Fixed a bug where local variables of calling functions were sometimes incorrectly visible to called functions.
• The ISINF, ISNAN, and ISFINITE functions now work for complex values.
• The %filescope directive now works as documented.
• Zero indexing on complex numbers is now supported.

• In prior releases, the Target Language Compiler allowed 0 indexing for integer and real values, but not for complex values. This restriction has been removed in the Target Language Compiler 4.1, as shown in the following example.

  • %assign a = 1.0 + 3.0i 
    %assign b = a[0] %% zero index now allowed
    

• Fixed a crash that occurred if ROLL_ITERATIONS was called outside of a %roll construct. ROLL_ITERATIONS returns NULL if called outside of a %roll construct.
• TLC now allows use of any path separator character independent of operating system. You can use either \ or / as a path separator character on Unix or Windows).
• Fixed a bug in the compare for equality operation. 0.0 now compares equal to -0.0.

Real-Time Workshop 4.1 Release Notes

Bug Fixes