VisualDSP++ 4.5 Loader and Utilities Manual - Analog Devices

Loader for ADSP-2126x/2136x/2137x SHARC Processors
Uncompressed Streams
Following the compressed streams, the loader utility file includes the
uncompressed streams. The uncompressed streams include application
codes, conflicted with the code in the initialization blocks in the processor’s
memory spaces, and a final block. The uncompressed stream includes
only a final block if there is no conflicted code. The final block can have a
zero byte count. The final block indicates the end of the application to the
initialization code.
Overlay Compression
The loader utility compresses the code and data from the executable .dxe
and shared memory .sm files when the -compression command-line switch
is used alone, and leaves the code and data from the overlay (.ovl) files
uncompressed. The -compressionOverlay switch directs the loader utility
to compress the code and data from the .ovl files, in addition to compressing
the code and data from the .dxe and .sm files.
The -compressionOverlay switch must be used in conjunction with
-compression.
Booting Compressed Streams
Figure 5-8 shows the booting sequence of a loader file with compressed
streams. The loader file is pre-stored in the flash memory.
1. A a booting process is initialized by the processor.
2. The processor brings the 256 words of the boot kernel from the
flash memory to the processor’s memory for execution.
3. The decompression engine is brought in.
4. The compressed stream is brought in, then decompressed and
loaded into the memory.
VisualDSP++ 4.5 Loader and Utilities Manual 5-39