Re: [dtrace-discuss] accessing frame pointer

[Chad Mynhier]

On Fri, May 7, 2010 at 5:13 PM, tester <solaris.ident...@gmail.com> wrote:
>> # dtrace -n
>> 'pid$target::a:18{tracemem(copyin(uregs[R_FP] - 8, 64), 64)}' -c ./a.out
>
> Hello Chad,
>
> Why do you need to subtract 8 from FP? Thanks

The disassembly showed the value of x being stored at $fp - 4:

   a+0x14:                 d0 27 bf fc  st        %o0, [%fp - 0x4]

So I subtracted 8 and dumped the contents of memory from that location
so that we'd see that value '6' stored in the second (4-byte) word
from there.  A little bit sloppy, as I could have dumped memory at %fp
- 4 for exactly four bytes.

Chad
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