This is the mail archive of the gdb@sourceware.org mailing list for the GDB project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: GDB default breakpoint instruction for SuperH


Min ZOU wrote:
Hi,

I looked at this GDB (v6.4) source file: gdb/config/sh/tm-sh.h . In side, it specifies the default breakpoint instruction for SH, which causes GDB to insert 0xc320 (trapa #32) into target when breakpoint is set. See below:

#define DEPRECATED_BIG_REMOTE_BREAKPOINT { 0xc3, 0x20 } /* Used in remote.c *
/
#define DEPRECATED_LITTLE_REMOTE_BREAKPOINT { 0x20, 0xc3 } /* Used in remote.c *
/


I wonder why by default 0x20 is used instead of other number without knowing the target SuperH processor type ?

Thanks!


I don't think the target processor type is important here. The interesting thing is what your trap handler does with different numbers.


See sim/sh/gencode.c (look for 'trapa') and sim/sh/interp.c (function trap) to see what the simulator does with various trap numbers. It would appear that the the correct number is 0xc3.

Another place to look might be the SH Linux kernel, if that's where you intend to use it.

Andrew Stubbs


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]