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remote GDB problem reading instructions from FLASH (IXP425)


Hello,

I'm trying to debug code running from Flash on an IXDP425 (XScale) board. To do this, I'm using xscale-elf-gdb on the host, which communicates with the target via the Abatron BDI200 JTAG interface unit. Whenever the code hits a breakpoint in flash (which, I assume is a HW breakpoint, since it's in flash, and the code does stop), GDB on the host requests to read target memory for that 32-bit instruction. Unfortunately, this instruction resides in flash, which only supports 16-data reads.

I've observed this with "set debug remote" turned on:

 > /* Code hits hardware (I assume) breakpoint set at 0x50013b3c */
 >   Sending packet: $m50013b3c,4#be...Ack
 >   Packet received: E01
 >   Cannot access memory at address 0x50013b3c

Is there any way to get GDB to limit reads from within a certain memory range to 16-bits at a time? Or, at least to manually set the read size for instruction fetches to either 16 or 32, based on where I know I'm executing code?

I've tried setting the GDB variables 'set remote memory-read-packet-size' and 'set remote memory-write-packet-size' both to 2 (bytes), but it seemed to have no effect on GDB instruction fetches.


This is my interpretation of the evidence. Please correct me if I'm wrong.


Any help appreciated :-)
--Jon


-- Jonathan Wurtz Senior Software Engineer WorldGate Communications Phone: (215) 354-5135


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