8.9.4 Interface

The CRC generation function uses a mechanism similar to the copy table functionality. Using the syntax shown above in the linker command file allows specification of code/data sections that have CRC values computed and stored in the run time image. This section describes the table data structures created by the linker, and how to access this information from application code.

The CRC tables contain entries as detailed in the run-time-support header file crc_tbl.h, as illustrated in Figure 8-9.

Figure 8-9 CRC_TABLE Conceptual Model

The crc_tbl.h header file is included in Example 31. This file specifies the C structures created by the linker to manage CRC information. It also includes the specifications of the supported CRC algorithms. A full discussion of CRC algorithms is beyond the scope of this document, and the interested reader should consult the referenced document for a description of the fields shown in the table. The following fields are relevant to this document.

Name – text identifier of the algorithm, used by the programmer in the linker command file.
ID – the numeric identifier of the algorithm, stored by the linker in the crc_alg_ID member of each table entry.
Order – the number of bits used by the CRC calculation.
Polynomial – used by the CRC computation engine.
Initial Value – the initial value given to the CRC computation engine.