Download MATLAB SIMULINK 7 - DEVELOPING S-FUNCTIONS User`s guide

Introduction
Fully Inlined S-Functions
A fully inlined S-function builds your algorithm (block) into Simulink and the
Real-Time Workshop in a manner that is indistinguishable from a built-in
block. Typically, a fully inlined S-function requires you to implement your
algorithm twice: once for Simulink (C-MEX S-function) and once for the
Real-Time Workshop (TLC file). The complexity of the TLC file depends on the
complexity of your algorithm and the level of efficiency you’re trying to achieve
in the generated code. TLC files vary from simple to complex in structure.
Basic Files Required for Implementation
This section briefly describes what files and functions you’ll need to create
noninlined, wrapper, and fully inlined S-functions.
• Noninlined S-functions require the C-MEX S-function source code
(sfunction.c).
• Wrapper S-functions that inline a call to your algorithm (your C function)
require an sfunction.tlc file.
• Fully inlined S-functions require an sfunction.tlc file. Fully inlined
S-functions produce the optimal code for a parameterized S-function. This is
an S-function that operates in a specific mode dependent upon fixed
S-function parameter(s) that do not change during model execution. For a
given operating mode, the sfunction.tlc specifies the exact code that will
be generated to implement the algorithm for that mode. For example, the
direct-index lookup table S-function at the end of this chapter contains two
operating modes — one for evenly spaced x-data and one for unevenly
spaced x-data.
- Fully inlined S-functions using the mdlRTW S-function routine require the
placement of the mdlRTW routine in your S-function MEX-file,
sfunction.c. The mdlRTW routine lets you place information in model.rtw,
which is the file that is processed by the Target Language Compiler prior
to executing sfunction.tlc when generating code. This is useful in two
situations: when you want to rename tunable parameters in your
generated code, and when you want to introduce nontunable parameters
into your TLC file.
For S-functions to work correctly in the Simulink environment, a certain
amount of overhead code is necessary. When the Real-Time Workshop
generates code from models that contain S-functions (without sfunction.tlc
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