[asterisk-dev] [Code Review] dsp.c optimize goerztzel sample loops, in dtmf_detect, mf_detect and tone_detect

[Alec Davis]

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This is an automatically generated e-mail. To reply, visit:
https://reviewboard.asterisk.org/r/2093/
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Review request for Asterisk Developers.


Summary
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the dmtf_detector had to recalc the address from the amp[] for each of 8 calls to goerztzel_sample()
Now use similar optimization as was already done in tone_detect().

If we're counting just lines of code executed, originally for each of the 160 samples was 80, now 53. 

created code looked like this;
this code is repeated 8 times in dtmf_detect, at 8000 times a second.
677:dsp.c         ****                         goertzel_sample(s->td.dtmf.row_out, amp[j]);
 14299                  .loc 1 677 0
 14300 0d21 8B45E0      movl -32(%ebp),%eax
 14301 0d24 01C0        addl %eax,%eax
 14302 0d26 034510      addl 16(%ebp),%eax
 14303 0d29 0FB700      movzwl (%eax),%eax
 14304 0d2c 98          cwtl
 14305 0d2d 8B550C      movl 12(%ebp),%edx
 14306 0d30 81C29402    addl $660,%edx
 14306      0000

 14307 0d36 89442404    movl %eax,4(%esp)
 14308 0d3a 891424      movl %edx,(%esp)
 14309 0d3d E8EEF2FF    call goertzel_sample

=============================================================
Now this code is add once
 675:dsp.c         ****                         samp = amp[j];
 14281                  .loc 1 675 0
 14282 0cf1 8B45DC      movl -36(%ebp),%eax
 14283 0cf4 01C0        addl %eax,%eax
 14284 0cf6 034510      addl 16(%ebp),%eax
 14285 0cf9 0FB700      movzwl (%eax),%eax
 14286 0cfc 668945E6    movw %ax,-26(%ebp)
Now this code is repeated 8 times. 
 679:dsp.c         ****                         goertzel_sample(s->td.dtmf.row_out, samp);
 14298                  .loc 1 679 0
 14299 0d25 0FBF45E6    movswl -26(%ebp),%eax
 14300 0d29 8B550C      movl 12(%ebp),%edx
 14301 0d2c 81C29402    addl $660,%edx
 14301      0000
 14302 0d32 89442404    movl %eax,4(%esp)
 14303 0d36 891424      movl %edx,(%esp)
 14304 0d39 E8F2F2FF    call goertzel_sample


Diffs
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  trunk/main/dsp.c 371689 

Diff: https://reviewboard.asterisk.org/r/2093/diff


Testing
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Yes, DTMF anyway, still able for recognise digits dialled. 

Verified with spandsp 0.0.6 if SPANDSP_USE_FIXED_POINT is chosen


Thanks,

Alec

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