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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 – 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 ‘<samp><span class="samp">.profiler</span></samp>’ which holds all profiling information. |
| We define new pseudo operation ‘<samp><span class="samp">.profiler</span></samp>’ 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>‘<samp><span class="samp">.profiler flags,function_to_profile [, cycle_corrector, extra]</span></samp>’ |
| |
| <p>where: |
| |
| <dl> |
| <dl> |
| ‘<samp><span class="samp">flags</span></samp>’ 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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