Datasheet

MOTOROLA MCF5206e USER’S MANUAL Appendix B-i
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APPENDIX B
PORTING FROM M68000 FAMILY DEVICES
This section is an overview of the issues encountered when porting embedded development
tools to ColdFire
®
devices when starting with the M68000 Family devices.
B.1 C COMPILERS AND HOST SOFTWARE
For the purpose of this discussion, it is assumed that an embedded software development
tool chain consists of a “host” portion and a “target” portion. The host portion consists of tool
chain parts that execute on a desktop computer or workstation. The target portion of the tool
chain runs ColdFire executables on a physical ColdFire target board.
Compilers, assemblers, linkers, loaders, instruction set simulators, and the host portion of
debuggers are examples of host tools. Many host tools such as linkers and loaders that work
with the M68000 Family devices can also be used without modification with ColdFire
processors.
Although you can use an existing M68000 Family assembler and disassembler with
ColdFire devices, Motorola recommends modifying the assembler so that non-ColdFire
assembly code cannot be put together in the executable. This is especially true if the
assembler assembles handwritten code. Porting the disassembler is for convenience and
can be performed later.
Debuggers usually are comprised of two parts. A host portion of the debugger typically
issues higher level commands for the target portion of debugger target. The target portion
of the debugger typically handles the exact details of the implementation of tracing,
breakpoints, and other lower level details. The debugger host portion requires little
modification. Most likely, the only architectural items of concern are the following:
• Differences in the designed supervisor registers and stack pointers (for displaying
registers)
• Interpretation of exception stack frames (if not already performed by the target portion)
B.2 TARGET SOFTWARE PORT
Porting ROM monitors and operating systems can begin after the compiler and assembler
have been ported. For example, consider the steps involved in porting a ROM debugger.
Similar issues are encountered when porting an RTOS and target applications.
It is assumed that target software consists of C and assembly source code. The first step is
to create executables that runs on existing M68000 Family hardware to test the conversion
from M68000 Family code to the proper ColdFire subset. This step verifies that the process
of code conversion does not introduce new errors.
Fr
eescale S
emiconduct
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Freescale Semiconductor, Inc.
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