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Re: STEP_SKIPS_DELAY question, sort of


Orjan Friberg wrote:
Andrew Cagney wrote:

I also think this needs a new macro name that better reflects what the test is doing. But I've no good ideas :-/ (SINGLE_STEP_THROUGH_DELAY (pc)?)

I'm facing a slightly different situation than the MIPS case when implementing SINGLE_STEP_THROUGH_DELAY, because the size of the instruction that the delay slot belongs to may be 2, 4, or 6 bytes. (For MIPS, it seems the size of that instruction is always 4 bytes.)


So, I have to find out the size of the preceding instruction (since I want to do the single-step thingy when we're stopped in the delay slot), but I can't find anything in the opcodes directory that would let me do that.

The thing is, this information (whether I'm in a delay slot, and the address of the instruction the delay slot belongs to) is available in a register. Besides the fact that this triggers sending a 'g' packet to the remote target, is it wrong to deduce this information from the registers content rather than reading from the program's text segment?

Basically, my implementation would look like this:

int
cris_single_step_through_delay (CORE_ADDR pc)
{
  ULONGEST erp;
  int ret = 0;
  regcache_cooked_read_unsigned (current_regcache, ERP_REGNUM, &erp);
  if (erp & 0x1)
    /* In delay slot - check if there's a breakpoint at the preceding
       instruction.  */
    if (breakpoint_here_p (erp & ~0x1))
      ret = 1;
  return ret;
}

--
Orjan Friberg
Axis Communications


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