Design Project Specifications
Specifications for the protected mode bootable debugger
- It should be able to boot into
protected mode from a floppy
- It should support single stepping
through the user plugged in code
- The user should be able to plug in
some machine code at a specified memory location from a floppy by
specifying , sector and track.
- However the machine code given by the
user to be debugged should be a protected mode ring 3 32 bit code.
- The debugger should be capable of
dumping the contents of registers
- The debugger should also be able
to dump the specified no. of bytes from a given segment:offset onto
- The debugger should be able to
print contents of the 386 tables like IDT,GDT,LDT,TSS.
- The user should be able to change
its register contents.
- As the debugger is running in
protected mode the BIOS routines for I/O cannot be used.
- The debugging will be done with
the support of the debug registers ,software breakpoints and the tracing capabilities provided by 386.
CaveatBeing a bare bones bootup program , it
will not implement the following :
- No support for paging will be
- There will be no filesystem
support for the floppy ie the user will have to specify the size
and location of the code in terms of sector and track no.
- This debugger can only be used to debug
protected mode code , hence we can't debug the bootup sequence as it works in
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