National Instruments AutoCode NI MATRIX - Manual (Page 79)

Chapter 3 Ada Language Reference
© National Instruments Corporation 3-17 AutoCode Reference
Fixed-Point Data Types
Fixed-point type declarations exist in the file named: sa_fxptypes_.a
and is provided in the System-Specific Files src (source) directory. 1
This file contains the specification of the SA_FIXED package. The package
specification contains all of the type declarations with the appropriate
delta and range for each type. Refer to the AutoCode Reference for more
information about the fixed-point type sizes, radix ranges and naming
conventions.
Note Ada uses the term delta to describe the accuracy of a fixed-point type.
AutoCode/Ada uses the term radix to denote a type’s accuracy. The relationship between
the two is: delta = 2
–radix . Thus, a fixed-point type with a delta of 0.125 is a fixed-point type
with radix 3.
Generic Functions
Generic functions that implement functionality of standard operations
are found in the two files named:
sa_fxpgenerics_.a and
sa_fxpgenerics.a . These files provide the specification and body for
the SA_FIXED_GENERICS package. These files are also provided in the
System-Specific Files src directory. These generic functions are the basis
for the creation of the overloaded operators to perform the appropriate
arithmetic operation.
Instantiated Functions
Due to the large number of combinations of operations and fixed-point
types, only those operations that are used in the model are
instantiated—that is, only the instances of the functions that are required by
a model are actually created. Thus, an additional file is created by the code
generator when generating code for a model that uses fixed-point types.
This file is generated from the template. The default template generates one
additional file that contains a package specification containing all of the
instantiated functions for the model. The package name is
RT_FIXED_OPERATORS and the file is named fxp_ outputfile_.a ,
where outputfile is the name of the model or other name as specified in
a command option to AutoCode.
1 The file name convention uses an underscore before the extension to denote a file containing a package specification.
The
.a extension is arbitrary as different platforms use different extensions, like .ada .