VisualDSP++ 4.5 Loader and Utilities Manual - Analog Devices

Loader for ADSP-2106x/21160 SHARC Processors
kernel executes from the reset vector, once the DMA that overwrites the
kernel is complete. A last remnant of the kernel code is left at the reset
vector location to replace the RTI with the user’s intended code. Because
of this last kernel remnant, user application code should not use the first
location of the reset vector. This first location should be a NOP or IDLE
instruction. The kernel automatically completes, and the program controller
begins sequencing the user application code at the second location
in the processor reset vector space.
When the boot process is complete, the processor automatically executes
the user application code. The only remaining evidence of the boot kernel
is at the first location of the interrupt vector. Almost no memory is sacrificed
to the boot code.
Boot Kernel Modification and Loader Issues
Some systems require boot kernel customization. The operation of other
tools (such as the C/C++ compiler) is influenced by whether the boot kernel
is used.
When producing a boot-loadable file, the loader utility reads a processor
executable file and uses information in it to initialize the memory. However,
the loader utility cannot determine how the processor SYSCON and
WAIT registers are to be configured for external memory loading in the
system.
If you modify the boot kernel by inserting values for your system, you
must rebuild it before generating the boot-loadable file. The boot kernel
contains default values for SYSCON. The initialization code can be found in
the comments in the boot kernel source file.
VisualDSP++ 4.5 Loader and Utilities Manual 3-19