360 lines
10 KiB
C
360 lines
10 KiB
C
#include <stdint.h>
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#include <stdlib.h>
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#include "DFT12Small.h"
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#include <math.h>
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#include <stdio.h>
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#define MAX_FREQS (12)
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#define OCTAVES (4)
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/*
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General procedure - use this code, with uint16_t or uint32_t buffers, and make sure none of the alarms go off.
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All of the paths still require no more than an 8-bit multiply.
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You should test with extreme cases, like square wave sweeps in, etc.
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*/
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//#define TWELVEBIT
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#define EIGHTBIT
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#ifdef TWELVEBIT
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//No larger than 12-bit signed values for integration or sincos
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#define FRONTEND_AMPLITUDE (0)
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#define INITIAL_DECIMATE (2)
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#define INTEGRATOR_DECIMATE (8)
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#define FINAL_DECIMATE (4)
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#elif defined( EIGHTBIT )
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//No larger than 8-bit signed values for integration or sincos
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#define FRONTEND_AMPLITUDE (2)
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#define INITIAL_DECIMATE (5) //Yurgh... only 3 bits of ADC data. That's 8 unique levels :(
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#define INTEGRATOR_DECIMATE (8)
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#define FINAL_DECIMATE (1)
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#endif
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//Right now, we need 8*freqs*octaves bytes.
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//This is bad.
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//What can we do to fix it?
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//4x the hits (sin/cos and we need to do it once for each edge)
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//8x for selecting a higher octave.
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#define FREQREBASE 8.0
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#define TARGFREQ 10000.0
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/* Tradeoff guide:
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* We will optimize for RAM size here.
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* INITIAL_DECIMATE; A larger decimation: {NOTE 1}
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+) Reduces the bit depth needed for the integral map.
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If you use "1" and a fully saturted map (highest note is every sample), it will not overflow a signed 12-bit number.
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-) Increases noise.
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With full-scale: 0->1 minimal 1->2 minimal 2->3 significantly noticable, 3->4 major.
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If sound is quieter, it matters more. Not sure with other changes in system. (2) seems ok.
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-) If you make it (1) or (0) You can't do an 8-bit multiply and keep the output in a signed range.
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Also, other things, like frequency of hits can manipulate the maximum bit depth needed for integral map.
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* If you weight the bins in advance see "mulmux", you can: {NOTE 2}
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+) potentially use shallower bit depth but
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-) have to compute the multiply every time you update the bin.
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* You can use a modified-square-wave which only integrates for 1/2 of the duty cycle. {NOTE 3}
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+) uses 1/2 the integral memory.
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-) Not as pretty of an output. See "integral_at"
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*TODO: Investigate using all unsigned (to make multiply and/or 12-bit storage easier)
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*TODO: Consider a mode which has 16-bit integrals, but still 8-bit cossin data.
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So, the idea here is we would keep a running total of the current ADC value, kept away in a int16_t.
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It is constantly summing, so we can take an integral of it. Or rather an integral range.
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Over time, we perform operations like adding or subtracting from a current place. It basically is
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a DFT where the kernel is computed using square waves (or modified square waves)
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*/
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//These live in RAM.
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int16_t running_integral; //Realistically treat as 12-bits on ramjet8
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int16_t integral_at[MAX_FREQS*OCTAVES]; //For ramjet8, make 12-bits
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int32_t cossindata[MAX_FREQS*OCTAVES*2]; //Contains COS and SIN data. (32-bit for now, will be 16-bit, potentially even 8.)
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uint8_t which_octave_for_op[MAX_FREQS]; //counts up, tells you which ocative you are operating on. PUT IN RAM.
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uint8_t actiontableplace;
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#define NR_OF_OPS (4<<OCTAVES)
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//Format is:
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// 255 = DO NOT OPERATE
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// bits 0..3 unfolded octave, i.e. sin/cos are offset by one.
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// bit 4 = add or subtract.
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uint8_t optable[NR_OF_OPS]; //PUT IN FLASH
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#define ACTIONTABLESIZE 256
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uint16_t actiontable[ACTIONTABLESIZE]; //PUT IN FLASH // If there are more than 8 freqbins, this must be a uint16_t, otherwise if more than 16, 32.
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//Format is
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uint8_t mulmux[MAX_FREQS]; //PUT IN FLASH
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static int Setup( float * frequencies, int bins )
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{
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int i;
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printf( "BINS: %d\n", bins );
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float highestf = frequencies[MAX_FREQS-1];
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for( i = 0; i < MAX_FREQS; i++ )
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{
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mulmux[i] = (uint8_t)( highestf / frequencies[i] * 255 + 0.5 );
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printf( "MM: %d %f / %f\n", mulmux[i], frequencies[i], highestf );
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}
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for( i = bins-MAX_FREQS; i < bins; i++ )
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{
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int topbin = i - (bins-MAX_FREQS);
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float f = frequencies[i]/FREQREBASE;
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float hits_per_table = (float)ACTIONTABLESIZE/f;
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int dhrpertable = (int)(hits_per_table+.5);//TRICKY: You might think you need to have even number of hits (sin/cos), but you don't! It can flip sin/cos each time through the table!
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float err = (TARGFREQ/((float)ACTIONTABLESIZE/dhrpertable) - (float)TARGFREQ/f)/((float)TARGFREQ/f);
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//Perform an op every X samples. How well does this map into units of 1024?
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printf( "%d %f -> hits per %d: %f %d (%.2f%% error)\n", topbin, f, ACTIONTABLESIZE, (float)ACTIONTABLESIZE/f, dhrpertable, err * 100.0 );
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if( dhrpertable >= ACTIONTABLESIZE )
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{
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fprintf( stderr, "Error: Too many hits.\n" );
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exit(0);
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}
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float advance_per_step = dhrpertable/(float)ACTIONTABLESIZE;
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float fvadv = 0.5;
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int j;
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int countset = 0;
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//Tricky: We need to start fadv off at such a place that there won't be a hicchup when going back around to 0.
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// I believe this is done by setting fvadv to 0.5 initially. Unsure.
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for( j = 0; j < ACTIONTABLESIZE; j++ )
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{
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if( fvadv >= 0.5 )
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{
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actiontable[j] |= 1<<topbin;
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fvadv -= 1.0;
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countset++;
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}
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fvadv += advance_per_step;
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}
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printf( " countset: %d\n", countset );
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}
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//exit(1);
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int phaseinop[OCTAVES] = { 0 };
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int already_hit_octaveplace[OCTAVES*2] = { 0 };
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for( i = 0; i < NR_OF_OPS; i++ )
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{
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int longestzeroes = 0;
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int val = i & ((1<<OCTAVES)-1);
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for( longestzeroes = 0; longestzeroes < 255 && ( ((val >> longestzeroes) & 1) == 0 ); longestzeroes++ );
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//longestzeroes goes: 255, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, ...
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//This isn't great, because we need to also know whether we are attacking the SIN side or the COS side, and if it's + or -.
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//We can actually decide that out.
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if( longestzeroes == 255 )
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{
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//This is a nop. Emit a nop.
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optable[i] = 255;
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}
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else
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{
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longestzeroes = OCTAVES-1-longestzeroes; //Actually do octave 0 least often.
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int iop = phaseinop[longestzeroes]++;
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int toop = longestzeroes;
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int toopmon = (longestzeroes<<1) | (iop & 1);
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//if it's the first time an octave happened this set, flag it. This may be used later in the process.
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if( !already_hit_octaveplace[toopmon] )
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{
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already_hit_octaveplace[toopmon] = 1;
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toop |= 1<<5;
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}
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if( iop & 1 )
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{
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toop |= 1<<6;
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}
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//Handle add/subtract bit.
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if( iop & 2 ) toop |= 1<<4;
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optable[i] = toop;
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//printf( " %d %d %d\n", iop, val, longestzeroes );
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}
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//printf( "HBT: %d = %d\n", i, optable[i] );
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}
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//exit(1);
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return 0;
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}
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void Small12BitRun( int8_t adcval )
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{
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int16_t adcv = adcval;
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adcv *= FRONTEND_AMPLITUDE;
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if( adcv > 127 ) adcv = 127;
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if( adcv < -128 ) adcv = -128;
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running_integral += adcv>>INITIAL_DECIMATE;
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#define dprintf( ... )
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uint32_t action = actiontable[actiontableplace++];
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int n;
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dprintf( "%4d ", actiontableplace );
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for( n = 0; n < MAX_FREQS; n++ )
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{
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if( action & (1<<n) )
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{
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int ao = which_octave_for_op[n];
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int op = optable[ao];
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ao++;
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if( ao >= NR_OF_OPS ) ao = 0;
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which_octave_for_op[n] = ao;
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if( op == 255 )
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{
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dprintf( "*" ); //NOP
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}
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else
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{
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//int octaveplace = op & 0xf;
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//Tricky: We share the integral with SIN and COS.
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//We don't need to. It would produce a slightly cleaner signal. See: NOTE 3
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uint8_t octave = op & 0xf;
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uint8_t intindex = octave * MAX_FREQS + n;
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//int invoct = OCTAVES-1-octaveplace;
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int16_t diff;
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if( op & 0x10 ) //ADD
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{
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diff = integral_at[intindex] - running_integral;
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dprintf( "%c", 'a' + (op & 0xf) );
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}
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else //SUBTRACT
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{
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diff = running_integral - integral_at[intindex];
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dprintf( "%c", 'A' + (op & 0xf) );
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}
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integral_at[intindex] = running_integral;
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#ifdef TWELVEBIT
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if( diff > 2000 || diff < -2000 ) printf( "!!!!!!!!!!!! %d !!!!!!!!!!!\n", diff );
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#elif defined( EIGHTBIT )
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if( diff > 124 || diff < -124 ) printf( "!!!!!!!!!!!! %d !!!!!!!!!!!\n", diff );
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#endif
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uint8_t idx = ( intindex << 1 );
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if( op&(1<<6) )
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{
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idx |= 1;
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}
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//printf( "%d: %d + %d * %d >> 8 - %d\n", idx, cossindata[idx], diff, mulmux[idx/2], cossindata[idx]>>4 );
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uint8_t mulmuxval = mulmux[n];
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//Do you live on a super lame processor? {NOTE 4}
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//If you do, you might not have good signed multiply operations. So, an alternative mechanism is found here.
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// +) Able to more cleanly crush to an 8-bit multiply.
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// +) Gets extra bit of precision back, i.e. the sign bit is now used as a data bit.
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// -) More than 1 line of C code. Requires possible double invert.
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#if 1
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//Terrible processor, i.e. PMS133
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if( 0 && diff < 0 )
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{
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diff *= -1;
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diff >>= (OCTAVES-1-octave);
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if( diff > 250 ) printf( "!!!!!!!**** %d ****!!!!!!!\n", diff );
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diff = (uint16_t)diff * (uint16_t)mulmuxval;
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diff >>= INTEGRATOR_DECIMATE;
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diff *= -1;
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}
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else
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{
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diff >>= (OCTAVES-1-octave);
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if( diff > 250 ) printf( "!!!!!!!**** %d ****!!!!!!!\n", diff );
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diff = (uint16_t)diff * (uint16_t)mulmuxval;
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diff >>= INTEGRATOR_DECIMATE;
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}
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#else
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//Decent processor, i.e. ATTiny85.
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diff = ((diff>>(OCTAVES-1-octave)) * mulmuxval ) >> 6;
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#endif
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cossindata[idx] = cossindata[idx]
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+ diff
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- (cossindata[idx]>>4)
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;
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#ifdef EIGHTBIT
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if( cossindata[idx] > 0 ) cossindata[idx]--;
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if( cossindata[idx] < 0 ) cossindata[idx]++;
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#endif
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}
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}
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else
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{
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dprintf( " " );
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}
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}
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dprintf( "\n" );
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}
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void DoDFT12BitSmall( float * outbins, float * frequencies, int bins, const float * databuffer, int place_in_data_buffer, int size_of_data_buffer, float q, float speedup )
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{
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static int is_setup;
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if( !is_setup ) { is_setup = 1; Setup( frequencies, bins ); }
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static int last_place;
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int i;
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for( i = last_place; i != place_in_data_buffer; i = (i+1)%size_of_data_buffer )
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{
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int16_t ifr1 = (int16_t)( ((databuffer[i]) ) * 4095 );
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Small12BitRun( ifr1>>5 ); //5 = Actually only feed algorithm numbers from -128 to 127.
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}
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last_place = place_in_data_buffer;
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static int idiv;
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idiv++;
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#if 1
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for( i = 0; i < bins; i++ )
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{
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int iss = cossindata[i*2+0]>>FINAL_DECIMATE;
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int isc = cossindata[i*2+1]>>FINAL_DECIMATE;
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int mux = iss * iss + isc * isc;
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if( mux <= 0 )
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{
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outbins[i] = 0;
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}
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else
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{
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outbins[i] = sqrt((float)mux)/50.0;
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#ifdef TWELVEBIT
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if( abs( cossindata[i*2+0] ) > 1000 || abs( cossindata[i*2+1] ) > 1000 )
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printf( "CS OVF %d/%d/%d/%f\n", i, cossindata[i*2+0], cossindata[i*2+1],outbins[i] );
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#elif defined( EIGHTBIT )
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if( abs( cossindata[i*2+0] ) > 120 || abs( cossindata[i*2+1] ) > 120 )
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printf( "CS OVF %d/%d/%d/%f\n", i, cossindata[i*2+0], cossindata[i*2+1],outbins[i] );
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#endif
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}
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}
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#endif
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}
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