Hi Tomas Tomas Frydrych wrote:
> On 05/03/12 08:30, Tomas Frydrych wrote: >> On 04/03/12 19:37, John Dallaway wrote: >>> However, this success was achieved using arm-eabi-gdb 6.8.50.20080706. >>> There does appear to be an issue with the length of the 'g' packet when >>> using the new arm-eabi-gdb 7.3.1: >>> >>>> (gdb) tar rem /dev/ttyS0 >>>> Remote debugging using /dev/ttyS0 >>>> Remote 'g' packet reply is too long: >>>> e14e000810000000000000001000000000000000000000000000000000000000000000000000000000000000fccf0d6800000000e8cf0d6895680008e24e00080000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000021 >>>> (gdb) >>> We will need to look into why the packet length has apparently changed >>> for Cortex-M targets. I can connect to an ARM7 target using the new GDB >>> without problem. >> >> This is a mismatch between the number of registers a gdb server reports >> and the number that gdb expects for the given architecture. In this case >> too many registers are being reported. IIRC, there should be 8 hex >> digits for a register, so the above string seems to represent 42 >> registers instead of the 21 that Cortex-M has. Looks like a bug in the >> monitor stub code, or perhaps a work around for something broken in >> older toolchains? > > Done bit further digging around the sources, > hal/cortexm/arch/.../cortexm_stub.h:64 defines 16 gpr, 8 fp or 12 bytes > each and 2 ps registers; this adds up to the 336 bytes of the above output. Yes. It looks like the FPA registers have been dropped from the default register set for Cortex-M targets in recent GDB. In the longer term, we should add a CDL option to our GDB stub code to accommodate this change. In the short term, I will look at creating a GDB target description file that we can use to accommodate the larger register set returned by our stubs. John Dallaway eCos maintainer http://www.dallaway.org.uk/john
