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Run-Time Environment Specification Files
Motorola
Software-Hardware Integration
For More Information On This Product,
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6-1
Chapter 6
Software-Hardware Integration
6.1 Overview
This chapter explains how the run-time environment may be changed and provides
examples of some changes and their effects. The run-time environment provided with the
compiler assumes, as a default, that the simulator is the target execution device. Several
aspects of the default run-time environment must be altered in order to adapt the compiler
to work with a custom hardware configuration.
The files which are alterable are discussed and classified according to effect. Aspects of
the run-time environment such as: bootstrapping, interrupts and memory management are
addressed individually.
6.2 Run-Time Environment Specification Files
The run-time environment is specified by three assembly language files: crt056[x,y,l].asm,
signal56[x,y,l].asm and setjmp56[x,y,l].asm where x, y, or l denote the memory model
(see chapters 2 and 4). These files may need to be modified if the run-time environment is
to be customized.
The
crt0
file contains parameters which specify the C bootstrap code, memory
configuration, memory management, interrupt vectors and other miscellaneous code. This
file must be modified to match the software and hardware configuration because the
memory configuration and interrupt vectors are determined by the hardware. The
information in this manual on the crt0 file applies to DSP56KCC Version g1.11. The crt0
file may be different for other versions of this compiler.
The signal file, which is equivalent to a hardware interrupt, is implemented in the C
environment. The signal file contains the code and data structures used to implement the
signal()
and
raise()
library functions. Changing this file is not recommended unless
necessary since any change to this file requires detailed knowledge of the DSP56000
family interrupt mechanism in addition to the signal and raise functions. This file is
closely tied to the signal.h file.
The
setjmp
file contains code which implements the functions
setjmp()
and
longjmp()
.
This file will probably never need to be modified unless the signal file is changed;
however, if either the
setjmp
file or setjmp.h are modified, the code in both files must be
made consistent. The source code for
setjmp()
and
longjmp()
is provided with
DSP56KCC to allow modification should the signal mechanism need to be changed.
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Freescale Semiconductor, Inc.
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