User`s guide

Introduction
4-5
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-TimeWorkshop (TLC file). The complexity of the TLC file depends on the
complexity of your algorithm and thelevel of efficiency you’re trying to achieve
in the generated code. TLC files vary from simple t o 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-functionsproduce 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.ThemdlRTW routine letsyou placeinformationin 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