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<title>Graphic Equalizer 2: C:/Project Marcel & Oliver/Graphic_Equalizer/src/fft.hcc Source File</title>
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<a class="el" href="dir_000000.html">C:</a> / <a class="el" href="dir_000001.html">Project Marcel & Oliver</a> / <a class="el" href="dir_000002.html">Graphic_Equalizer</a> / <a class="el" href="dir_000004.html">src</a></div>
<h1>fft.hcc</h1><a href="fft_8hcc.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001
00020 <span class="preprocessor">#include <stdlib.hch></span>
00021 <span class="preprocessor">#include "pal_master.hch"</span>
00022
00023 <span class="preprocessor">#include "<a class="code" href="audio_8hch.html">audio.hch</a>"</span>
00024 <span class="preprocessor">#include "<a class="code" href="weights__256_8hch.html">weights_256.hch</a>"</span>
00025 <span class="preprocessor">#include "<a class="code" href="configuration_8hch.html">configuration.hch</a>"</span>
00026 <span class="preprocessor">#include "xilinxmult.hch"</span>
00027 <span class="preprocessor">#include "<a class="code" href="fft_8hch.html">fft.hch</a>"</span>
00028
00029 <span class="preprocessor">#if HAVE_DEBUG</span>
00030 <span class="preprocessor"></span><span class="preprocessor"> #include "debug.hch"</span>
00031 <span class="preprocessor">#endif</span>
00032 <span class="preprocessor"></span>
00033 <span class="comment">/* Define two multi-port RAMs for FFT calculation; one for real and one for imaginary values</span>
00034 <span class="comment"> * Extra block RAM settings are defined to make sure read and write actions can be performed</span>
00035 <span class="comment"> * within one clock-cycle.</span>
00036 <span class="comment"> * Left out extra settings on new board the clock changes TODO !!!!</span>
00037 <span class="comment"> */</span>
00038 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00039 <span class="preprocessor"></span>mpram
00040 {
00041 ram <span class="keywordtype">signed</span> 18 rwrite[256];
00042 rom <span class="keywordtype">signed</span> 18 read[256];
00043 } real with {block = <span class="stringliteral">"BlockRAM"</span><span class="comment">/*, westart=2.5, welength=1, rclkpos={1.5}, wclkpos={3}, clkpulselen=0.5*/</span>};
00044
00045 mpram
00046 {
00047 ram <span class="keywordtype">signed</span> 18 rwrite[256];
00048 rom <span class="keywordtype">signed</span> 18 read[256];
00049 } imaginary with {block = <span class="stringliteral">"BlockRAM"</span><span class="comment">/*, westart=2.5, welength=1, rclkpos={1.5}, wclkpos={3}, clkpulselen=0.5*/</span>};
00050 <span class="preprocessor">#else</span>
00051 <span class="preprocessor"></span>mpram
00052 {
00053 ram <span class="keywordtype">signed</span> 24 rwrite[256];
00054 rom <span class="keywordtype">signed</span> 24 read[256];
00055 } real with {block = <span class="stringliteral">"BlockRAM"</span><span class="comment">/*, westart=2.5, welength=1, rclkpos={1.5}, wclkpos={3}, clkpulselen=0.5*/</span>};
00056
00057 mpram
00058 {
00059 ram <span class="keywordtype">signed</span> 24 rwrite[256];
00060 rom <span class="keywordtype">signed</span> 24 read[256];
00061 } imaginary with {block = <span class="stringliteral">"BlockRAM"</span><span class="comment">/*, westart=2.5, welength=1, rclkpos={1.5}, wclkpos={3}, clkpulselen=0.5*/</span>};
00062 <span class="preprocessor">#endif</span>
00063 <span class="preprocessor"></span><span class="comment">// multiplication factors for equalizer function</span>
<a name="l00064"></a><a class="code" href="fft_8hcc.html#a1">00064</a> ram <span class="keywordtype">signed</span> 7 <a class="code" href="fft_8hcc.html#a1">eq_settings</a>[16] = {0,2,4,7,10,13,16,19,22,26,30,35,41,48,55,63};
00065
00066 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00067 <span class="preprocessor"></span><span class="preprocessor">#define DC_COMPONENT 0</span>
00068 <span class="preprocessor"></span><span class="preprocessor">#else</span>
<a name="l00069"></a><a class="code" href="fft_8hcc.html#a0">00069</a> <span class="preprocessor"></span><span class="preprocessor">#define DC_COMPONENT 8470527</span>
00070 <span class="preprocessor"></span><span class="preprocessor">#endif</span>
00071 <span class="preprocessor"></span>
<a name="l00082"></a><a class="code" href="fft_8hcc.html#a2">00082</a> macro proc <a class="code" href="fft_8hcc.html#a2">multiply</a>(result, op_a, op_b)
00083 {
00084 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00085 <span class="preprocessor"></span> xilinxmult(result, op_a, adjs(op_b,18));
00086 <span class="preprocessor">#else</span>
00087 <span class="preprocessor"></span> result = (adjs(op_a,38))*(adjs(op_a,38));
00088 <span class="preprocessor">#endif </span>
00089 <span class="preprocessor"></span>}
00090
00091
00092
00093
<a name="l00104"></a><a class="code" href="fft_8hcc.html#a3">00104</a> <span class="keywordtype">void</span> <a class="code" href="fft_8hcc.html#a3">calculate_fft</a>(<span class="keywordtype">unsigned</span> 1 select_inverse)
00105 {
00106 <span class="keywordtype">unsigned</span> 4 level;
00107 <span class="keywordtype">unsigned</span> 8 point1,point2,j,f,k;
00108 <span class="keywordtype">unsigned</span> 9 e,i;
00109 <span class="keywordtype">signed</span> 16 weight1,weight2;
00110 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00111 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 p,q,r,t;
00112 <span class="preprocessor">#else</span>
00113 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 24 p,q,r,t;
00114 <span class="preprocessor">#endif</span>
00115 <span class="preprocessor"></span> <span class="keywordtype">signed</span> a,b;
00116
00117 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00118 <span class="preprocessor"></span> <span class="comment">// Macro to provide rescaling of 36-bit result of fixed point multiply</span>
00119 <span class="comment">// down to an 18-bit result. The range of bits selected depends on the </span>
00120 <span class="comment">// number that represents the value of "1" in the trig function lookup</span>
00121 <span class="comment">// tables. (Eg. for 16384 == 1, the lowest bit selected should be [14]).</span>
00122 macro expr rescale (x) = (x[35] @ x[30:14]);
00123 <span class="preprocessor">#else</span>
00124 <span class="preprocessor"></span> <span class="comment">//Macro to rescale the multiply result down to a 24-bit value.</span>
00125 macro expr rescale (x) = ((x>>FRACBITS)<-24);
00126 <span class="preprocessor">#endif</span>
00127 <span class="preprocessor"></span>
00128 <span class="keywordflow">for</span>(level=1;level<=NUMBER_OF_COLUMNS;level++) <span class="comment">// count all the columns</span>
00129 {
00130 e=1<<(<a class="code" href="fft_8hch.html#a0">NUMBER_OF_COLUMNS</a>-level+1); <span class="comment">// number of points in each block in this column</span>
00131 f=(e>>1)<-8; <span class="comment">// number of butterflies in each block in this column</span>
00132
00133 <span class="keywordflow">for</span>(j=1;j<=f;j++) <span class="comment">// count all the butterflies in each block</span>
00134 {
00135 par
00136 {
00137 <span class="comment">// Weight factors for real (the same for FFT and iFFT)</span>
00138 weight1 = <a class="code" href="weights__256_8hch.html#a2">weight_re</a>[((j-1)<<(level-1))<-7];
00139
00140
00141 <span class="comment">// Weight factors for imaginary (opposite for FFT and iFFT)</span>
00142 weight2 = (!select_inverse) ? (<a class="code" href="weights__256_8hch.html#a3">weight_im</a>[((j-1)<<(level-1))<-7]) : -(<a class="code" href="weights__256_8hch.html#a3">weight_im</a>[((j-1)<<(level-1))<-7]);
00143
00144 <span class="comment">/* ORIGINAL CODE BELOW, MODIFIED BECAUSE OF MISMATCHING OUTPUT WITH BORLAND TESTAPP</span>
00145 <span class="comment"> weight2 = (!select_inverse) ? -(weight_im[((j-1)<<(level-1))<-7]) : weight_im[((j-1)<<(level-1))<-7]; </span>
00146 <span class="comment"> */</span>
00147
00148
00149
00150 <span class="keywordflow">for</span>(i=0@j;i<=NUMBER_OF_POINTS;i+=e) <span class="comment">// count all the blocks in this column</span>
00151 { <span class="comment">// Butterfly calculation</span>
00152 par
00153 {
00154 point1 = ((i<-8)-1);
00155 point2 = (((i<-8)+f)-1);
00156 }
00157
00158 par
00159 {
00160 p = (real.read[point1] >> 1) + (real.rwrite[point2] >> 1);
00161 q = (imaginary.read[point1] >> 1) + (imaginary.rwrite[point2] >> 1);
00162 }
00163
00164 par
00165 {
00166 r = (real.read[point1] >> 1) - (real.rwrite[point2] >> 1);
00167 t = (imaginary.read[point1] >> 1) - (imaginary.rwrite[point2] >> 1);
00168 }
00169
00170 <a class="code" href="fft_8hcc.html#a2">multiply</a>(a,r,weight1);
00171 <a class="code" href="fft_8hcc.html#a2">multiply</a>(b,t,weight2);
00172
00173 par
00174 {
00175 real.rwrite[point2] = (rescale(a-b));
00176 imaginary.rwrite[point1] = q;
00177 }
00178
00179 <a class="code" href="fft_8hcc.html#a2">multiply</a>(a,t,weight1);
00180 <a class="code" href="fft_8hcc.html#a2">multiply</a>(b,r,weight2);
00181
00182 par
00183 {
00184 real.rwrite[point1] = p;
00185 imaginary.rwrite[point2] = (rescale(a+b));
00186 }
00187
00188 }
00189 }
00190 }
00191 }
00192
00193 j=1;
00194 <span class="keywordflow">for</span>(i=1;i<NUMBER_OF_POINTS;i++)
00195 {
00196 <span class="keywordflow">if</span>(i<(0@j))
00197 {
00198 par
00199 {
00200 point1=j-1;
00201 point2=(i-1)<-8;
00202 }
00203 <span class="comment">/*</span>
00204 <span class="comment"> COPYING ARRAY VALUES FROM ONE PLACE TO ANOTHER IN THE ARRAT MUST BE DONE IN </span>
00205 <span class="comment"> 2 STEPS. FIRSTLY THE VALUES ARE COPIED TO SEPARATE VARIABLES AFTER THAT THEY</span>
00206 <span class="comment"> ARE COPIED BACK TO THEIR NEW POSITION IN THE ARRAY. THIS MUST BE DONE TO </span>
00207 <span class="comment"> PREVENT TIMING ISSUES FROM OCCURING.</span>
00208 <span class="comment"> */</span>
00209 par
00210 {
00211 p = real.read[point1];
00212 q = imaginary.read[point1];
00213 }
00214 par
00215 {
00216 r = real.read[point2];
00217 t = imaginary.read[point2];
00218 }
00219 par
00220 {
00221 real.rwrite[point1] = r;
00222 imaginary.rwrite[point1] = t;
00223 }
00224 par
00225 {
00226 real.rwrite[point2] = p;
00227 imaginary.rwrite[point2] = q;
00228 }
00229 }
00230
00231 k = <a class="code" href="fft_8hch.html#a1">NUMBER_OF_POINTS</a>>>1;
00232
00233
00234 <span class="keywordflow">while</span>(k<j)
00235 {
00236 j = j-k;
00237 k = k>>1;
00238 }
00239
00240 j+=k;
00241 }
00242
00243 }
00244
00256 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00257 <span class="preprocessor"></span><span class="keywordtype">void</span> <a class="code" href="fft_8hcc.html#a4">perform_fft</a>(<span class="keywordtype">signed</span> 18 *pcm_audio)
00258 #<span class="keywordflow">else</span>
<a name="l00259"></a><a class="code" href="fft_8hcc.html#a4">00259</a> <span class="keywordtype">void</span> <a class="code" href="fft_8hcc.html#a4">perform_fft</a>(<span class="keywordtype">signed</span> 16 *pcm_audio)
00260 #endif
00261 {
00262 <span class="keywordtype">unsigned</span> 8 k;
00263 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00264 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 sample;
00265 k=0;
00266 sample = adjs(pcm_audio[k],18);
00267 <span class="preprocessor">#else</span>
00268 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 24 sample;
00269 k=0;
00270 sample = adjs(pcm_audio[k],24);
00271 <span class="preprocessor">#endif</span>
00272 <span class="preprocessor"></span>
00273 <span class="comment">//initialize variables for the copying pipeline</span>
00274
00275
00276 <span class="comment">// copy audio data to real-array before starting FFT calculation</span>
00277 <span class="comment">// and set imaginary values to zero</span>
00278 <span class="keywordflow">do</span>
00279 {
00280 <span class="comment">//Copying the array values has been pipelined to prevent parallel access to the</span>
00281 <span class="comment">//pcm_audio array. This copying procedure must be finished before another </span>
00282 <span class="comment">//sample is read from the audio input. The time available for this loop is </span>
00283 <span class="comment">//determined by the sampling rate of 44,1 Khz</span>
00284 par
00285 {
00286 <span class="comment">//COPYING NEEDS TO BE DONE IN 2 STEPS, BECAUSE THE VALUE THAT NEEDS TO WRITTEN</span>
00287 <span class="comment">//TO THE REAL-RAM NEEDS TO BE AVAILABLE ON THE START OFF THE CLOCKCYCLE.</span>
00288 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00289 <span class="preprocessor"></span> sample = adjs(pcm_audio[k+1],18);
00290 <span class="preprocessor">#else</span>
00291 <span class="preprocessor"></span> sample = adjs(pcm_audio[k+1],24);
00292 <span class="preprocessor">#endif</span>
00293 <span class="preprocessor"></span> real.rwrite[k] = sample;
00294 imaginary.rwrite[k] = 0;
00295 k++;
00296 }
00297 } <span class="keywordflow">while</span> (k);
00298
00299
00300
00301 <span class="preprocessor">#if PERFORM_FFT_CALCULATION</span>
00302 <span class="preprocessor"></span> <a class="code" href="fft_8hcc.html#a3">calculate_fft</a>(0);
00303 <span class="preprocessor">#endif</span>
00304 <span class="preprocessor"></span>
00305
00306 }
00307
00321 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00322 <span class="preprocessor"></span><span class="keywordtype">void</span> <a class="code" href="fft_8hcc.html#a5">perform_ifft</a>(<span class="keywordtype">signed</span> 18 *modified_audio, <span class="keywordtype">unsigned</span> 6 *ifft_info)
00323 #<span class="keywordflow">else</span>
<a name="l00324"></a><a class="code" href="fft_8hcc.html#a5">00324</a> <span class="keywordtype">void</span> <a class="code" href="fft_8hcc.html#a5">perform_ifft</a>(<span class="keywordtype">signed</span> 16 *modified_audio, <span class="keywordtype">unsigned</span> 6 *ifft_info)
00325 #endif
00326 {
00327 <span class="keywordtype">unsigned</span> 6 k;
00328 <span class="preprocessor">#if HARDWARE_MULTIPLY </span>
00329 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 p;
00330 <span class="preprocessor">#else</span>
00331 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 24 p;
00332 <span class="preprocessor">#endif</span>
00333 <span class="preprocessor"></span><span class="preprocessor">#if PERFORM_FFT_CALCULATION </span>
00334 <span class="preprocessor"></span> <a class="code" href="fft_8hcc.html#a3">calculate_fft</a>(1);
00335 <span class="preprocessor">#endif</span>
00336 <span class="preprocessor"></span>
00337 k=0;
00338 <span class="comment">//initialize variables for the copying pipeline</span>
00339 <span class="preprocessor">#if PERFORM_FFT_CALCULATION </span>
00340 <span class="preprocessor"></span><span class="preprocessor"> #if HARDWARE_MULTIPLY </span>
00341 <span class="preprocessor"></span> p = (real.read[(0@k)+95] << NUMBER_OF_COLUMNS);
00342 <span class="preprocessor"> #else</span>
00343 <span class="preprocessor"></span> p = (real.read[(0@k)+95] >> NUMBER_OF_COLUMNS);
00344 <span class="preprocessor"> #endif</span>
00345 <span class="preprocessor"></span><span class="preprocessor">#else</span>
00346 <span class="preprocessor"></span> p = (real.read[(0@k)+95]);
00347 <span class="preprocessor">#endif</span>
00348 <span class="preprocessor"></span>
00349 <span class="keywordflow">do</span>
00350 {
00351 <span class="comment">//Copying the array values has been pipelined to prevent parallel access to the</span>
00352 <span class="comment">//pcm_audio array. This copying procedure must be finished before another </span>
00353 <span class="comment">//sample is read from the audio input. The time available for this loop is </span>
00354 <span class="comment">//determined by the sampling rate of 44,1 Khz</span>
00355 par
00356 {
00357 <span class="comment">/*</span>
00358 <span class="comment"> * Before copying the modified audio from the local real-array </span>
00359 <span class="comment"> * to the output array of the audio I/O component, compensate</span>
00360 <span class="comment"> * for the FFT calculation by shifting the values. </span>
00361 <span class="comment"> * 95 is added to start the output from the middle of the sliding</span>
00362 <span class="comment"> * window, this is done to get a better sound quality.</span>
00363 <span class="comment"> */</span>
00364 <span class="preprocessor">#if PERFORM_FFT_CALCULATION </span>
00365 <span class="preprocessor"></span><span class="preprocessor"> #if HARDWARE_MULTIPLY </span>
00366 <span class="preprocessor"></span> p = (real.read[(0@k)+95] << NUMBER_OF_COLUMNS);
00367 <span class="preprocessor"> #else</span>
00368 <span class="preprocessor"></span> p = (real.read[(0@k)+95] >> NUMBER_OF_COLUMNS);
00369 <span class="preprocessor"> #endif</span>
00370 <span class="preprocessor"></span><span class="preprocessor">#else</span>
00371 <span class="preprocessor"></span> p = (real.read[(0@k)+95]);
00372 <span class="preprocessor">#endif</span>
00373 <span class="preprocessor"></span> <span class="comment">//Copy the modified audio from the local real array to the output array of the audio I/O component.</span>
00374 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00375 <span class="preprocessor"></span> modified_audio[k] = p ;
00376 <span class="preprocessor">#else</span>
00377 <span class="preprocessor"></span> modified_audio[k] = (p<-16);
00378 <span class="preprocessor">#endif</span>
00379 <span class="preprocessor"></span> <span class="comment">//Fill the array for displaying the waveform, only the 6 MSB are needed.</span>
00380 ifft_info[k] = (<span class="keywordtype">unsigned</span> 6)(32+(p[17:12]));
00381 k++;
00382 }
00383 } <span class="keywordflow">while</span>(k);
00384 }
00385
<a name="l00398"></a><a class="code" href="fft_8hcc.html#a6">00398</a> <span class="keywordtype">void</span> <a class="code" href="fft_8hcc.html#a6">equalize_audio</a>(<a class="code" href="structaudiodata__t.html">audiodata_t</a> *audiodata)
00399 {
00400 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00401 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 p,q;
00402 <span class="preprocessor">#else</span>
00403 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 24 p,q;
00404 <span class="preprocessor">#endif</span>
00405 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 a;
00406 <span class="keywordtype">unsigned</span> 8 i, mirror_i, bit, m, n;
00407 <span class="keywordtype">unsigned</span> 7 old_value;
00408 <span class="keywordtype">unsigned</span> 9 tmp;
00409
00410 <span class="comment">//macro expr equalize_bar = multiply(q,a)[29:6];</span>
00411
00412 macro proc equalize_bar(retval)
00413 {
00414 <span class="keywordtype">signed</span> result;
00415 <a class="code" href="fft_8hcc.html#a2">multiply</a>(result, q,a);
00416 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00417 <span class="preprocessor"></span> retval = result[23:6]; <span class="comment">//drop last 6 bit to compensate the maximum multiplication with 64 from the eq_settings array</span>
00418 <span class="preprocessor">#else</span>
00419 <span class="preprocessor"></span> retval = result[29:6]; <span class="comment">//drop last 6 bit to compensate the maximum multiplication with 64 from the eq_settings array</span>
00420 <span class="preprocessor">#endif</span>
00421 <span class="preprocessor"></span> }
00422
00423 p = real.read[0] - DC_COMPONENT; <span class="comment">// remove DC component for calculations</span>
00424 real.rwrite[0] = p;
00425
00426 <span class="keywordflow">for</span>(i=0;i!=NUMBER_OF_FREQUENCIES;i++)
00427 {
00428
00429 <span class="comment">// set multiplication factor (0..64) for current frequency bar, The first frequency band must be equalized at 100% (63) since there is no DC-component taken into account.</span>
00430 a = adjs(<a class="code" href="fft_8hcc.html#a1">eq_settings</a>[audiodata-><a class="code" href="structaudiodata__t.html#o0">equalizer_levels_ptr</a>[i <- 7]],18);
00431
00432
00433 <span class="comment">// multiply frequency with this factor and divide by 64 (drop 6 LSB's)</span>
00434 q = real.read[i];
00435 equalize_bar(p);
00436 real.rwrite[i] = p;
00437
00438 q = imaginary.read[i];
00439 equalize_bar(p);
00440 imaginary.rwrite[i] = p;
00441
00442 <span class="comment">// the upper part(128..255) of the spectrum is mirrored to the lower part; </span>
00443 <span class="comment">// these values need to be adjusted too</span>
00444 <span class="keywordflow">if</span> ((i<-7)!=0) <span class="comment">// if not in DC component bar</span>
00445 {
00446 mirror_i = (<a class="code" href="fft_8hch.html#a1">NUMBER_OF_POINTS</a>-1)-i+1;
00447 q = real.read[mirror_i];
00448 equalize_bar(p);
00449 real.rwrite[mirror_i] = p;
00450
00451 q = imaginary.read[mirror_i];
00452 equalize_bar(p);
00453 imaginary.rwrite[mirror_i] = p;
00454 }
00455 }
00456
00457 <span class="comment">//write data to fft_info for display purposes</span>
00458 <span class="keywordflow">for</span>(i=0;i<NUMBER_OF_FREQUENCIES;i++)
00459 {
00460 p = real.read[i];
00461 q = imaginary.read[i];
00462 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00463 <span class="preprocessor"></span> <span class="keywordflow">if</span> (p[17] == 1) p = -p; <span class="keywordflow">else</span> delay;
00464 <span class="keywordflow">if</span> (q[17] == 1) q = -q; <span class="keywordflow">else</span> delay;
00465 <span class="preprocessor">#else</span>
00466 <span class="preprocessor"></span> <span class="keywordflow">if</span> (p[23] == 1) p = -p; <span class="keywordflow">else</span> delay;
00467 <span class="keywordflow">if</span> (q[23] == 1) q = -q; <span class="keywordflow">else</span> delay;
00468 <span class="preprocessor">#endif</span>
00469 <span class="preprocessor"></span> p = (p<q) ? q : p; <span class="comment">// This is done to get the best visual frequency result</span>
00470
00471 <span class="keywordflow">if</span> (!audiodata-><a class="code" href="structaudiodata__t.html#o1">display_log</a>)
00472 {
00473
00474 bit=126;
00475 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00476 <span class="preprocessor"></span> <span class="keywordflow">while</span> ((p[15] == 0) && (bit != 0))
00477 <span class="preprocessor">#else</span>
00478 <span class="preprocessor"></span> <span class="keywordflow">while</span> ((p[21] == 0) && (bit != 0))
00479 <span class="preprocessor">#endif</span>
00480 <span class="preprocessor"></span> par
00481 {
00482 p = p<<1;
00483 bit = bit - 18;
00484 }
00485 old_value = audiodata->fft_info.write[0 @ (i <- 7)];
00486 tmp = ((0@old_value) + (0@bit))>>1;
00487 audiodata->fft_info.write[0 @ (i <- 7)] = (old_value <= (tmp<-7)) ? (tmp<-7) : old_value-1;
00488 }
00489 <span class="keywordflow">else</span>
00490 {
00491 old_value = audiodata->fft_info.write[0 @ (i <- 7)];
00492 <span class="preprocessor">#if HARDWARE_MULTIPLY</span>
00493 <span class="preprocessor"></span> audiodata->fft_info.write[0 @ (i <- 7)] = (old_value<=(unsigned)(p[15:9])) ? (unsigned)(p[15:9]) : old_value-1;
00494 <span class="preprocessor">#else</span>
00495 <span class="preprocessor"></span> audiodata->fft_info.write[0 @ (i <- 7)] = (old_value<=(unsigned)(p[21:15])) ? (unsigned)(p[21:15]) : old_value-1;
00496 <span class="preprocessor">#endif</span>
00497 <span class="preprocessor"></span> }
00498 }
00499
00500 <span class="comment">// add DC component again before inverse FFT calculation is performed</span>
00501
00502 p = real.read[0] + DC_COMPONENT;
00503 real.rwrite[0] = p;
00504 }
00505
</pre></div><hr size="1"><address style="align: right;"><small>Generated on Thu Dec 9 14:37:07 2004 for Graphic Equalizer 2 by
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