diff options
Diffstat (limited to 'Graphic_Equalizer/doc/html/fft_8hcc-source.html')
| -rw-r--r-- | Graphic_Equalizer/doc/html/fft_8hcc-source.html | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/Graphic_Equalizer/doc/html/fft_8hcc-source.html b/Graphic_Equalizer/doc/html/fft_8hcc-source.html new file mode 100644 index 0000000..64569fd --- /dev/null +++ b/Graphic_Equalizer/doc/html/fft_8hcc-source.html @@ -0,0 +1,436 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"> +<title>Graphic Equalizer: C:/Project Marcel & Oliver/Graphic_Equalizer/src/fft.hcc Source File</title> +<link href="doxygen.css" rel="stylesheet" type="text/css"> +</head><body> +<!-- Generated by Doxygen 1.3.9.1 --> +<div class="qindex"><a class="qindex" href="main.html">Main Page</a> | <a class="qindex" href="files.html">File List</a> | <a class="qindex" href="globals.html">Globals</a></div> +<div class="nav"> +<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 "weights_256.hch"</span> +00025 <span class="preprocessor">#include "<a class="code" href="configuration_8hch.html">configuration.hch</a>"</span> +00026 <span class="preprocessor">#include "debug.hch"</span> +00027 <span class="preprocessor">#include "xilinxmult.hch"</span> +00028 +00029 <span class="comment">/* Define two multi-port RAMs for FFT calculation; one for real and one for imaginary values</span> +00030 <span class="comment"> * Extra block RAM settings are defined to make sure read and write actions can be performed</span> +00031 <span class="comment"> * within one clock-cycle.</span> +00032 <span class="comment"> * Left out extra settings on new board the clock changes TODO !!!!</span> +00033 <span class="comment"> */</span> +00034 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00035 <span class="preprocessor"></span>mpram +00036 { +00037 ram <span class="keywordtype">signed</span> 18 rwrite[256]; +00038 rom <span class="keywordtype">signed</span> 18 read[256]; +00039 } 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>}; +00040 +00041 mpram +00042 { +00043 ram <span class="keywordtype">signed</span> 18 rwrite[256]; +00044 rom <span class="keywordtype">signed</span> 18 read[256]; +00045 } 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>}; +00046 <span class="preprocessor">#else</span> +00047 <span class="preprocessor"></span>mpram +00048 { +00049 ram <span class="keywordtype">signed</span> 24 rwrite[256]; +00050 rom <span class="keywordtype">signed</span> 24 read[256]; +00051 } 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>}; +00052 +00053 mpram +00054 { +00055 ram <span class="keywordtype">signed</span> 24 rwrite[256]; +00056 rom <span class="keywordtype">signed</span> 24 read[256]; +00057 } 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>}; +00058 <span class="preprocessor">#endif</span> +00059 <span class="preprocessor"></span><span class="comment">// multiplication factors for equalizer function</span> +00060 ram <span class="keywordtype">signed</span> 7 eq_settings[16] = {0,2,4,7,10,13,16,19,22,26,30,35,41,48,55,63}; +00061 +00062 +<a name="l00073"></a><a class="code" href="fft_8hcc.html#a1">00073</a> macro proc <a class="code" href="fft_8hcc.html#a1">multiply</a>(result, op_a, op_b) +00074 { +00075 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00076 <span class="preprocessor"></span> xilinxmult(result, op_a, adjs(op_b,18)); +00077 <span class="preprocessor">#else</span> +00078 <span class="preprocessor"></span> result = (adjs(op_a,38))*(adjs(op_a,38)); +00079 <span class="preprocessor">#endif </span> +00080 <span class="preprocessor"></span>} +00081 +00082 +00083 +00084 +<a name="l00095"></a><a class="code" href="fft_8hcc.html#a2">00095</a> <span class="keywordtype">void</span> <a class="code" href="fft_8hcc.html#a2">calculate_fft</a>(<span class="keywordtype">unsigned</span> 1 select_inverse) +00096 { +00097 <span class="keywordtype">unsigned</span> 4 level; +00098 <span class="keywordtype">unsigned</span> 8 point1,point2,j,f,k; +00099 <span class="keywordtype">unsigned</span> 9 e,i; +00100 <span class="keywordtype">signed</span> 16 weight1,weight2; +00101 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00102 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 p,q,r,t; +00103 <span class="preprocessor">#else</span> +00104 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 24 p,q,r,t; +00105 <span class="preprocessor">#endif</span> +00106 <span class="preprocessor"></span> <span class="keywordtype">signed</span> a,b; +00107 +00108 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00109 <span class="preprocessor"></span> <span class="comment">// Macro to provide rescaling of 36-bit result of fixed point multiply</span> +00110 <span class="comment">// down to an 18-bit result. The range of bits selected depends on the </span> +00111 <span class="comment">// number that represents the value of "1" in the trig function lookup</span> +00112 <span class="comment">// tables. (Eg. for 16384 == 1, the lowest bit selected should be [14]).</span> +00113 macro expr rescale (x) = (x[35] @ x[30:14]); +00114 <span class="preprocessor">#else</span> +00115 <span class="preprocessor"></span> <span class="comment">//Macro to rescale the multiply result down to a 24-bit value.</span> +00116 macro expr rescale (x) = ((x>>FRACBITS)<-24); +00117 <span class="preprocessor">#endif</span> +00118 <span class="preprocessor"></span> +00119 <span class="keywordflow">for</span>(level=1;level<=NUMBER_OF_COLUMNS;level++) <span class="comment">// count all the columns</span> +00120 { +00121 e=1<<(NUMBER_OF_COLUMNS-level+1); <span class="comment">// number of points in each block in this column</span> +00122 f=(e>>1)<-8; <span class="comment">// number of butterflies in each block in this column</span> +00123 +00124 <span class="keywordflow">for</span>(j=1;j<=f;j++) <span class="comment">// count all the butterflies in each block</span> +00125 { +00126 par +00127 { +00128 <span class="comment">// Weight factors for real (the same for FFT and iFFT)</span> +00129 weight1 = weight_re[((j-1)<<(level-1))<-7]; +00130 +00131 +00132 <span class="comment">// Weight factors for imaginary (opposite for FFT and iFFT)</span> +00133 weight2 = (!select_inverse) ? (weight_im[((j-1)<<(level-1))<-7]) : -(weight_im[((j-1)<<(level-1))<-7]); +00134 +00135 <span class="comment">/* ORIGINAL CODE BELOW, MODIFIED BECAUSE OF MISMATCHING OUTPUT WITH BORLAND TESTAPP</span> +00136 <span class="comment"> weight2 = (!select_inverse) ? -(weight_im[((j-1)<<(level-1))<-7]) : weight_im[((j-1)<<(level-1))<-7]; </span> +00137 <span class="comment"> */</span> +00138 +00139 +00140 +00141 <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> +00142 { <span class="comment">// Butterfly calculation</span> +00143 par +00144 { +00145 point1 = ((i<-8)-1); +00146 point2 = (((i<-8)+f)-1); +00147 } +00148 +00149 par +00150 { +00151 p = (real.read[point1] >> 1) + (real.rwrite[point2] >> 1); +00152 q = (imaginary.read[point1] >> 1) + (imaginary.rwrite[point2] >> 1); +00153 } +00154 +00155 par +00156 { +00157 r = (real.read[point1] >> 1) - (real.rwrite[point2] >> 1); +00158 t = (imaginary.read[point1] >> 1) - (imaginary.rwrite[point2] >> 1); +00159 } +00160 +00161 <a class="code" href="fft_8hcc.html#a1">multiply</a>(a,r,weight1); +00162 <a class="code" href="fft_8hcc.html#a1">multiply</a>(b,t,weight2); +00163 +00164 par +00165 { +00166 real.rwrite[point2] = (rescale(a-b)); +00167 imaginary.rwrite[point1] = q; +00168 } +00169 +00170 <a class="code" href="fft_8hcc.html#a1">multiply</a>(a,t,weight1); +00171 <a class="code" href="fft_8hcc.html#a1">multiply</a>(b,r,weight2); +00172 +00173 par +00174 { +00175 real.rwrite[point1] = p; +00176 imaginary.rwrite[point2] = (rescale(a+b)); +00177 } +00178 +00179 } +00180 } +00181 } +00182 } +00183 +00184 j=1; +00185 <span class="keywordflow">for</span>(i=1;i<NUMBER_OF_POINTS;i++) +00186 { +00187 <span class="keywordflow">if</span>(i<(0@j)) +00188 { +00189 par +00190 { +00191 point1=j-1; +00192 point2=(i-1)<-8; +00193 } +00194 <span class="comment">/*</span> +00195 <span class="comment"> COPYING ARRAY VALUES FROM ONE PLACE TO ANOTHER IN THE ARRAT MUST BE DONE IN </span> +00196 <span class="comment"> 2 STEPS. FIRSTLY THE VALUES ARE COPIED TO SEPARATE VARIABLES AFTER THAT THEY</span> +00197 <span class="comment"> ARE COPIED BACK TO THEIR NEW POSITION IN THE ARRAY. THIS MUST BE DONE TO </span> +00198 <span class="comment"> PREVENT TIMING ISSUES FROM OCCURING.</span> +00199 <span class="comment"> */</span> +00200 par +00201 { +00202 p = real.read[point1]; +00203 q = imaginary.read[point1]; +00204 } +00205 par +00206 { +00207 r = real.read[point2]; +00208 t = imaginary.read[point2]; +00209 } +00210 par +00211 { +00212 real.rwrite[point1] = r; +00213 imaginary.rwrite[point1] = t; +00214 } +00215 par +00216 { +00217 real.rwrite[point2] = p; +00218 imaginary.rwrite[point2] = q; +00219 } +00220 } +00221 +00222 k = NUMBER_OF_POINTS>>1; +00223 +00224 +00225 <span class="keywordflow">while</span>(k<j) +00226 { +00227 j = j-k; +00228 k = k>>1; +00229 } +00230 +00231 j+=k; +00232 } +00233 +00234 } +00235 +00247 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00248 <span class="preprocessor"></span><span class="keywordtype">void</span> perform_fft(<span class="keywordtype">signed</span> 18 *pcm_audio) +00249 #<span class="keywordflow">else</span> +00250 <span class="keywordtype">void</span> perform_fft(<span class="keywordtype">signed</span> 16 *pcm_audio) +00251 #endif +00252 { +00253 <span class="keywordtype">unsigned</span> 8 k; +00254 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00255 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 sample; +00256 k=0; +00257 sample = adjs(pcm_audio[k],18); +00258 <span class="preprocessor">#else</span> +00259 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 24 sample; +00260 k=0; +00261 sample = adjs(pcm_audio[k],24); +00262 <span class="preprocessor">#endif</span> +00263 <span class="preprocessor"></span> +00264 <span class="comment">//initialize variables for the copying pipeline</span> +00265 +00266 +00267 <span class="comment">// copy audio data to real-array before starting FFT calculation</span> +00268 <span class="comment">// and set imaginary values to zero</span> +00269 <span class="keywordflow">do</span> +00270 { +00271 <span class="comment">//Copying the array values has been pipelined to prevent parallel access to the</span> +00272 <span class="comment">//pcm_audio array. This copying procedure must be finished before another </span> +00273 <span class="comment">//sample is read from the audio input. The time available for this loop is </span> +00274 <span class="comment">//determined by the sampling rate of 44,1 Khz</span> +00275 par +00276 { +00277 <span class="comment">//COPYING NEEDS TO BE DONE IN 2 STEPS, BECAUSE THE VALUE THAT NEEDS TO WRITTEN</span> +00278 <span class="comment">//TO THE REAL-RAM NEEDS TO BE AVAILABLE ON THE START OFF THE CLOCKCYCLE.</span> +00279 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00280 <span class="preprocessor"></span> sample = adjs(pcm_audio[k+1],18); +00281 <span class="preprocessor">#else</span> +00282 <span class="preprocessor"></span> sample = adjs(pcm_audio[k+1],24); +00283 <span class="preprocessor">#endif</span> +00284 <span class="preprocessor"></span> real.rwrite[k] = sample; +00285 imaginary.rwrite[k] = 0; +00286 k++; +00287 } +00288 } <span class="keywordflow">while</span> (k); +00289 +00290 +00291 +00292 <span class="preprocessor">#if PERFORM_FFT_CALCULATION</span> +00293 <span class="preprocessor"></span> <a class="code" href="fft_8hcc.html#a2">calculate_fft</a>(0); +00294 <span class="preprocessor">#endif</span> +00295 <span class="preprocessor"></span> +00296 +00297 } +00298 +00312 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00313 <span class="preprocessor"></span><span class="keywordtype">void</span> perform_ifft(<span class="keywordtype">signed</span> 18 *modified_audio, <span class="keywordtype">unsigned</span> 6 *ifft_info) +00314 #<span class="keywordflow">else</span> +00315 <span class="keywordtype">void</span> perform_ifft(<span class="keywordtype">signed</span> 16 *modified_audio, <span class="keywordtype">unsigned</span> 6 *ifft_info) +00316 #endif +00317 { +00318 <span class="keywordtype">unsigned</span> 6 k; +00319 <span class="preprocessor">#if HARDWARE_MULTIPLY </span> +00320 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 p; +00321 <span class="preprocessor">#else</span> +00322 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 24 p; +00323 <span class="preprocessor">#endif</span> +00324 <span class="preprocessor"></span><span class="preprocessor">#if PERFORM_FFT_CALCULATION </span> +00325 <span class="preprocessor"></span> <a class="code" href="fft_8hcc.html#a2">calculate_fft</a>(1); +00326 <span class="preprocessor">#endif</span> +00327 <span class="preprocessor"></span> +00328 k=0; +00329 <span class="comment">//initialize variables for the copying pipeline</span> +00330 <span class="preprocessor">#if PERFORM_FFT_CALCULATION </span> +00331 <span class="preprocessor"></span><span class="preprocessor"> #if HARDWARE_MULTIPLY </span> +00332 <span class="preprocessor"></span> p = (real.read[(0@k)+95] << NUMBER_OF_COLUMNS); +00333 <span class="preprocessor"> #else</span> +00334 <span class="preprocessor"></span> p = (real.read[(0@k)+95] >> NUMBER_OF_COLUMNS); +00335 <span class="preprocessor"> #endif</span> +00336 <span class="preprocessor"></span><span class="preprocessor">#else</span> +00337 <span class="preprocessor"></span> p = (real.read[(0@k)+95]); +00338 <span class="preprocessor">#endif</span> +00339 <span class="preprocessor"></span> +00340 <span class="keywordflow">do</span> +00341 { +00342 <span class="comment">//Copying the array values has been pipelined to prevent parallel access to the</span> +00343 <span class="comment">//pcm_audio array. This copying procedure must be finished before another </span> +00344 <span class="comment">//sample is read from the audio input. The time available for this loop is </span> +00345 <span class="comment">//determined by the sampling rate of 44,1 Khz</span> +00346 par +00347 { +00348 <span class="comment">/*</span> +00349 <span class="comment"> * Before copying the modified audio from the local real-array </span> +00350 <span class="comment"> * to the output array of the audio I/O component, compensate</span> +00351 <span class="comment"> * for the FFT calculation by shifting the values. </span> +00352 <span class="comment"> * 95 is added to start the output from the middle of the sliding</span> +00353 <span class="comment"> * window, this is done to get a better sound quality.</span> +00354 <span class="comment"> */</span> +00355 <span class="preprocessor">#if PERFORM_FFT_CALCULATION </span> +00356 <span class="preprocessor"></span><span class="preprocessor"> #if HARDWARE_MULTIPLY </span> +00357 <span class="preprocessor"></span> p = (real.read[(0@k)+95] << NUMBER_OF_COLUMNS); +00358 <span class="preprocessor"> #else</span> +00359 <span class="preprocessor"></span> p = (real.read[(0@k)+95] >> NUMBER_OF_COLUMNS); +00360 <span class="preprocessor"> #endif</span> +00361 <span class="preprocessor"></span><span class="preprocessor">#else</span> +00362 <span class="preprocessor"></span> p = (real.read[(0@k)+95]); +00363 <span class="preprocessor">#endif</span> +00364 <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> +00365 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00366 <span class="preprocessor"></span> modified_audio[k] = p ; +00367 <span class="preprocessor">#else</span> +00368 <span class="preprocessor"></span> modified_audio[k] = (p<-16); +00369 <span class="preprocessor">#endif</span> +00370 <span class="preprocessor"></span> <span class="comment">//Fill the array for displaying the waveform, only the 6 MSB are needed.</span> +00371 ifft_info[k] = (<span class="keywordtype">unsigned</span> 6)(32+(p[17:12])); +00372 k++; +00373 } +00374 } <span class="keywordflow">while</span>(k); +00375 } +00376 +<a name="l00389"></a><a class="code" href="fft_8hcc.html#a5">00389</a> <span class="keywordtype">void</span> <a class="code" href="fft_8hcc.html#a5">equalize_audio</a>(audiodata_t *audiodata) +00390 { +00391 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00392 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 p,q; +00393 <span class="preprocessor">#else</span> +00394 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 24 p,q; +00395 <span class="preprocessor">#endif</span> +00396 <span class="preprocessor"></span> <span class="keywordtype">signed</span> 18 a; +00397 <span class="keywordtype">unsigned</span> 8 i, mirror_i, bit, m, n; +00398 <span class="keywordtype">unsigned</span> 7 old_value; +00399 <span class="keywordtype">unsigned</span> 9 tmp; +00400 +00401 <span class="comment">//macro expr equalize_bar = multiply(q,a)[29:6];</span> +00402 +00403 macro proc equalize_bar(retval) +00404 { +00405 <span class="keywordtype">signed</span> result; +00406 <a class="code" href="fft_8hcc.html#a1">multiply</a>(result, q,a); +00407 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00408 <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> +00409 <span class="preprocessor">#else</span> +00410 <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> +00411 <span class="preprocessor">#endif</span> +00412 <span class="preprocessor"></span> } +00413 +00414 p = real.read[0] - DC_COMPONENT; <span class="comment">// remove DC component for calculations</span> +00415 real.rwrite[0] = p; +00416 +00417 <span class="keywordflow">for</span>(i=0;i!=NUMBER_OF_FREQUENCIES;i++) +00418 { +00419 +00420 <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> +00421 a = adjs(eq_settings[audiodata->equalizer_levels_ptr[i <- 7]],18); +00422 +00423 +00424 <span class="comment">// multiply frequency with this factor and divide by 64 (drop 6 LSB's)</span> +00425 q = real.read[i]; +00426 equalize_bar(p); +00427 real.rwrite[i] = p; +00428 +00429 q = imaginary.read[i]; +00430 equalize_bar(p); +00431 imaginary.rwrite[i] = p; +00432 +00433 <span class="comment">// the upper part(128..255) of the spectrum is mirrored to the lower part; </span> +00434 <span class="comment">// these values need to be adjusted too</span> +00435 <span class="keywordflow">if</span> ((i<-7)!=0) <span class="comment">// if not in DC component bar</span> +00436 { +00437 mirror_i = (NUMBER_OF_POINTS-1)-i+1; +00438 q = real.read[mirror_i]; +00439 equalize_bar(p); +00440 real.rwrite[mirror_i] = p; +00441 +00442 q = imaginary.read[mirror_i]; +00443 equalize_bar(p); +00444 imaginary.rwrite[mirror_i] = p; +00445 } +00446 } +00447 +00448 <span class="comment">//write data to fft_info for display purposes</span> +00449 <span class="keywordflow">for</span>(i=0;i<NUMBER_OF_FREQUENCIES;i++) +00450 { +00451 p = real.read[i]; +00452 q = imaginary.read[i]; +00453 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00454 <span class="preprocessor"></span> <span class="keywordflow">if</span> (p[17] == 1) p = -p; <span class="keywordflow">else</span> delay; +00455 <span class="keywordflow">if</span> (q[17] == 1) q = -q; <span class="keywordflow">else</span> delay; +00456 <span class="preprocessor">#else</span> +00457 <span class="preprocessor"></span> <span class="keywordflow">if</span> (p[23] == 1) p = -p; <span class="keywordflow">else</span> delay; +00458 <span class="keywordflow">if</span> (q[23] == 1) q = -q; <span class="keywordflow">else</span> delay; +00459 <span class="preprocessor">#endif</span> +00460 <span class="preprocessor"></span> p = (p<q) ? q : p; <span class="comment">// This is done to get the best visual frequency result</span> +00461 +00462 <span class="keywordflow">if</span> (!audiodata->display_log) +00463 { +00464 +00465 bit=126; +00466 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00467 <span class="preprocessor"></span> <span class="keywordflow">while</span> ((p[15] == 0) && (bit != 0)) +00468 <span class="preprocessor">#else</span> +00469 <span class="preprocessor"></span> <span class="keywordflow">while</span> ((p[21] == 0) && (bit != 0)) +00470 <span class="preprocessor">#endif</span> +00471 <span class="preprocessor"></span> par +00472 { +00473 p = p<<1; +00474 bit = bit - 18; +00475 } +00476 old_value = audiodata->fft_info.write[0 @ (i <- 7)]; +00477 tmp = ((0@old_value) + (0@bit))>>1; +00478 audiodata->fft_info.write[0 @ (i <- 7)] = (old_value <= (tmp<-7)) ? (tmp<-7) : old_value-1; +00479 } +00480 <span class="keywordflow">else</span> +00481 { +00482 old_value = audiodata->fft_info.write[0 @ (i <- 7)]; +00483 <span class="preprocessor">#if HARDWARE_MULTIPLY</span> +00484 <span class="preprocessor"></span> audiodata->fft_info.write[0 @ (i <- 7)] = (old_value<=(unsigned)(p[15:9])) ? (unsigned)(p[15:9]) : old_value-1; +00485 <span class="preprocessor">#else</span> +00486 <span class="preprocessor"></span> audiodata->fft_info.write[0 @ (i <- 7)] = (old_value<=(unsigned)(p[21:15])) ? (unsigned)(p[21:15]) : old_value-1; +00487 <span class="preprocessor">#endif</span> +00488 <span class="preprocessor"></span> } +00489 } +00490 +00491 <span class="comment">// add DC component again before inverse FFT calculation is performed</span> +00492 +00493 p = real.read[0] + DC_COMPONENT; +00494 real.rwrite[0] = p; +00495 } +00496 +</pre></div><hr size="1"><address style="align: right;"><small>Generated on Mon Nov 29 12:04:47 2004 for Graphic Equalizer by +<a href="http://www.doxygen.org/index.html"> +<img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.3.9.1 </small></address> +</body> +</html> |