single-stepping remote target fails

Chad Phillips jcphillips@yahoo.com
Thu Jun 23 15:20:00 GMT 2005


I have rewritten basic support for MCORE for gdb-6.3.  Also, I have 
written a debug proxy application that accepts 'remote' connections from 
GDB via. socket and then manipulates the target using its JTAG/BDM 
interface.  Now for the problems....

Context: Code being executed on the target is in Flash.  As a result, I 
have only supported hardware breakpoints at this time.  Two hardware 
breakpoints are available through the MCORE JTAG port.

Problem 1.
Single stepping in C source only steps by single machine instruction.  I 
had expected that GDB might try to set breakpoints on the next 
instruction and then continue, but I see no such requests from GDB.  How 
does GDB cause single steps through C (any high level language) source?

Problem 2.
When I issue the step command (or si, n, ni) to the target, GDB does a 
_lot_ of memory reads.  It reads from the start of main up to the 
current PC (in main).  What is it doing, and how can I make it stop?

Thanks,
Chad



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