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<h4 class="subsection">9.29.6 Profiling Capability</h4>
<p><a name="index-MSP-430-profiling-capability-1764"></a><a name="index-profiling-capability-for-MSP-430-1765"></a>It is a performance hit to use gcc's profiling approach for this tiny target.
Even more &ndash; jtag hardware facility does not perform any profiling functions.
However we've got gdb's built-in simulator where we can do anything.
<p>We define new section &lsquo;<samp><span class="samp">.profiler</span></samp>&rsquo; which holds all profiling information.
We define new pseudo operation &lsquo;<samp><span class="samp">.profiler</span></samp>&rsquo; which will instruct assembler to
add new profile entry to the object file. Profile should take place at the
present address.
<p>Pseudo operation format:
<p>&lsquo;<samp><span class="samp">.profiler flags,function_to_profile [, cycle_corrector, extra]</span></samp>&rsquo;
<p>where:
<dl>
<dl>
&lsquo;<samp><span class="samp">flags</span></samp>&rsquo; is a combination of the following characters:
<dt><code>s</code><dd>function entry
<br><dt><code>x</code><dd>function exit
<br><dt><code>i</code><dd>function is in init section
<br><dt><code>f</code><dd>function is in fini section
<br><dt><code>l</code><dd>library call
<br><dt><code>c</code><dd>libc standard call
<br><dt><code>d</code><dd>stack value demand
<br><dt><code>I</code><dd>interrupt service routine
<br><dt><code>P</code><dd>prologue start
<br><dt><code>p</code><dd>prologue end
<br><dt><code>E</code><dd>epilogue start
<br><dt><code>e</code><dd>epilogue end
<br><dt><code>j</code><dd>long jump / sjlj unwind
<br><dt><code>a</code><dd>an arbitrary code fragment
<br><dt><code>t</code><dd>extra parameter saved (a constant value like frame size)
</dl>
<br><dt><code>function_to_profile</code><dd>a function address
<br><dt><code>cycle_corrector</code><dd>a value which should be added to the cycle counter, zero if omitted.
<br><dt><code>extra</code><dd>any extra parameter, zero if omitted.
</dl>
<p>For example:
<pre class="smallexample"> .global fxx
.type fxx,@function
fxx:
.LFrameOffset_fxx=0x08
.profiler "scdP", fxx ; function entry.
; we also demand stack value to be saved
push r11
push r10
push r9
push r8
.profiler "cdpt",fxx,0, .LFrameOffset_fxx ; check stack value at this point
; (this is a prologue end)
; note, that spare var filled with
; the farme size
mov r15,r8
...
.profiler cdE,fxx ; check stack
pop r8
pop r9
pop r10
pop r11
.profiler xcde,fxx,3 ; exit adds 3 to the cycle counter
ret ; cause 'ret' insn takes 3 cycles
</pre>
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