colorchord/embeddedcommon/DFT8Turbo.c

//NOTE DO NOT EDIT THIS FILE WITHOUT ALSO EDITING DFT12SMALL!!!

#include <stdint.h>
#include <stdlib.h>
#include "DFT8Turbo.h"
#include <math.h>

#include <stdio.h>

#define MAX_FREQS (12)
#define OCTAVES   (4)

/*
	General procedure - use this code, with uint16_t or uint32_t buffers, and make sure none of the alarms go off.
		All of the paths still require no more than an 8-bit multiply.
		You should test with extreme cases, like square wave sweeps in, etc.
*/

//No larger than 8-bit signed values for integration or sincos
#define FRONTEND_AMPLITUDE (2)
#define INITIAL_DECIMATE (5) //Yurgh... only 3 bits of ADC data.  That's 8 unique levels :(
#define INTEGRATOR_DECIMATE (8)
#define FINAL_DECIMATE (1)


#define OPTABLETYPE uint16_t	//Make uint8_t if on attiny.

//4x the hits (sin/cos and we need to do it once for each edge)
//8x for selecting a higher octave.
#define FREQREBASE 8.0 
#define TARGFREQ 10000.0

//These live in RAM.
int8_t running_integral; //Realistically treat as 12-bits on ramjet8
int8_t integral_at[MAX_FREQS*OCTAVES];	//For ramjet8, make 12-bits
int8_t cossindata[MAX_FREQS*OCTAVES*2]; //Contains COS and SIN data.  (32-bit for now, will be 16-bit, potentially even 8.)
uint8_t which_octave_for_op[MAX_FREQS]; //counts up, tells you which ocative you are operating on.  PUT IN RAM.
uint8_t actiontableplace;

#define NR_OF_OPS (4<<OCTAVES)
//Format is:
//  255 = DO NOT OPERATE
// bits 0..3 unfolded octave, i.e. sin/cos are offset by one.
// bit 4 = add or subtract.
OPTABLETYPE  optable[NR_OF_OPS]; //PUT IN FLASH

#define ACTIONTABLESIZE 256
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.
//Format is

OPTABLETYPE mulmux[MAX_FREQS];	//PUT IN FLASH

static int Setup( float * frequencies, int bins )
{
	int i;
	printf( "BINS: %d\n", bins );

	float highestf = frequencies[MAX_FREQS-1];
	for( i = 0; i < MAX_FREQS; i++ )
	{
		mulmux[i] = (uint8_t)( highestf / frequencies[i] * 255 + 0.5 );
		printf( "MM: %d  %f / %f\n", mulmux[i], frequencies[i], highestf );
	}

	for( i = bins-MAX_FREQS; i < bins; i++ )
	{
		int topbin = i - (bins-MAX_FREQS);
		float f = frequencies[i]/FREQREBASE; 
		float hits_per_table = (float)ACTIONTABLESIZE/f;
		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!
		float err = (TARGFREQ/((float)ACTIONTABLESIZE/dhrpertable) - (float)TARGFREQ/f)/((float)TARGFREQ/f);
		//Perform an op every X samples.  How well does this map into units of 1024?
		printf( "%d %f -> hits per %d: %f %d (%.2f%% error)\n", topbin, f, ACTIONTABLESIZE, (float)ACTIONTABLESIZE/f, dhrpertable, err * 100.0 );
		if( dhrpertable >= ACTIONTABLESIZE )
		{
			fprintf( stderr, "Error: Too many hits.\n" );
			exit(0);
		}

		float advance_per_step = dhrpertable/(float)ACTIONTABLESIZE;
		float fvadv = 0.5;
		int j;
		int countset = 0;

		//Tricky: We need to start fadv off at such a place that there won't be a hicchup when going back around to 0.
		//	I believe this is done by setting fvadv to 0.5 initially.  Unsure.

		for( j = 0; j < ACTIONTABLESIZE; j++ )
		{
			if( fvadv >= 0.5 )
			{
				actiontable[j] |= 1<<topbin;
				fvadv -= 1.0;
				countset++;
			}
			fvadv += advance_per_step;
		}
		printf( "   countset: %d\n", countset );
	}
	//exit(1);


	int phaseinop[OCTAVES] = { 0 };
	int already_hit_octaveplace[OCTAVES*2] = { 0 };
	for( i = 0; i < NR_OF_OPS; i++ )
	{
		int longestzeroes = 0;
		int val = i & ((1<<OCTAVES)-1);
		for( longestzeroes = 0; longestzeroes < 255 && ( ((val >> longestzeroes) & 1) == 0 ); longestzeroes++ );
		//longestzeroes goes: 255, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, ...
		//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 -.
		//We can actually decide that out.

		if( longestzeroes == 255 )
		{
			//This is a nop.  Emit a nop.
			optable[i] = 255;
		}
		else
		{
			longestzeroes = OCTAVES-1-longestzeroes;	//Actually do octave 0 least often.
			int iop = phaseinop[longestzeroes]++;
			int toop = longestzeroes;
			int toopmon = (longestzeroes<<1) | (iop & 1);

			//if it's the first time an octave happened this set, flag it. This may be used later in the process.
			if( !already_hit_octaveplace[toopmon] )
			{
				already_hit_octaveplace[toopmon] = 1;
				toop |= 1<<5;
			}
			if( iop & 1 )
			{
				toop |= 1<<6;
			}

			//Handle add/subtract bit.
			if( iop & 2 ) toop |= 1<<4;

			optable[i] = toop;

			//printf( "  %d %d %d\n", iop, val, longestzeroes );
		}
		//printf( "HBT: %d = %d\n", i, optable[i] );
	}
	//exit(1);

	return 0;
}


void Turbo8BitRun( int8_t adcval )
{
	int16_t adcv = adcval;
	adcv *= FRONTEND_AMPLITUDE;
	if( adcv > 127 ) adcv = 127;
	if( adcv < -128 ) adcv = -128;
	running_integral += adcv>>INITIAL_DECIMATE;

	uint16_t action = actiontable[actiontableplace++];
	uint8_t n;

	//Counts are approximate counts for PMS133

	for( n = 0; 			//1CYC
		 n < MAX_FREQS; 	//2CYC
		 n++, 				//1CYC
			action>>=1 		//2CYC
		)
	{
		//Everything inside this loop is executed ~3/4 * MAX_FREQS. so.. ~9x.
		//If op @ 4MHz, we get 44 cycles in here.

		//If no operation is scheduled, continue.
		if( !( action & 1 ) ) continue;		//1CYC

		uint8_t ao = which_octave_for_op[n];	//4CYC
		ao++;									//1CYC
		if( ao >= NR_OF_OPS ) ao = 0;			//2CYC
		which_octave_for_op[n] = ao;			//2CYC (idxm)

		uint8_t op = optable[ao];				//"theoretically" 3CYC (if you align things right)
												//1CYC (Put A into specific RAM location)

		//If we are on the one thing we aren't supposed to operate within, cancel.
		if( op == 255 )	continue;				//2CYC (if op is in A)

		//Tricky: We share the integral with SIN and COS.
		//We don't need to. It would produce a slightly cleaner signal. See: NOTE 3
		uint8_t octave = op & 0xf;				//1CYC (if op is in A)


		uint8_t intindex = octave * MAX_FREQS //Load mulop with 12 [2CYC]; mul [1CYC]
			 + n;								//Add [1CYC]
												//[1CYC] more cycle to write A into RAM[(intindex)
		//int invoct = OCTAVES-1-octaveplace;
		int8_t diff;

		if( op & 0x10 )	//ADD		//2CYC
		{
			diff = integral_at[intindex]		//Assume "IntIndex" is in A, add integral_at to A [1], move A to an index [1]. [2] to read into acc. [4CYC]
				 - running_integral;			//1CYC to subtract.
												//1CYC to write diff into a memory location.
		}
		else	//SUBTRACT
		{
			diff = running_integral - integral_at[intindex];
		}

		//30 cycles so far.

		integral_at[intindex] = running_integral;	//[3CYC]

		//if( diff > 124 || diff < -124 ) printf( "!!!!!!!!!!!! %d !!!!!!!!!!!\n", diff );
		
		//uint8_t idx = ( intindex << 1 );	//Overwrite intindex.
		intindex <<= 1; //1CYC

		if( op&(1<<6) )	//2CYC
		{
			intindex |= 1; //1CYC
		}

		uint8_t mulmuxval = mulmux[n];	//[4CYC]


		//Do you live on a super lame processor? {NOTE 4}
		//If you do, you might not have good signed multiply operations. So, an alternative mechanism is found here.
		//	+) Able to more cleanly crush to an 8-bit multiply.
		//	+) Gets extra bit of precision back, i.e. the sign bit is now used as a data bit.
		//	-) More than 1 line of C code.  Requires possible double invert.
#if 1
		//rough processor, i.e. PMS133
		if( diff < 0 )		//[2CYC]
		{
			diff *= -1;		//[1CYC]
			diff >>= (OCTAVES-1-octave); // ???TRICKY???
			//if( diff > 250 ) printf( "!!!!!!!**** %d ****!!!!!!!\n", diff );

			diff = ((uint16_t)diff * (uint16_t)mulmuxval)>>INTEGRATOR_DECIMATE; //[3CYC]
			diff *= -1; //[1CYC]
		}
		else
		{
			diff >>= (OCTAVES-1-octave);
			//if( diff > 250 ) printf( "!!!!!!!**** %d ****!!!!!!!\n", diff );
			diff = ((uint16_t)diff * (uint16_t)mulmuxval)>>INTEGRATOR_DECIMATE;
		}	

		//@48 cycles :( :( :(

#else
		//Decent processor, i.e. ATTiny85.
		diff = ((diff>>(OCTAVES-1-octave)) * mulmuxval ) >> 6;
#endif
		//printf( "%d\n", diff );

		cossindata[intindex] = cossindata[intindex] 
			+ diff
			- (cossindata[intindex]>>4)
			;

		if( cossindata[intindex] > 0 ) cossindata[intindex]--;
		if( cossindata[intindex] < 0 ) cossindata[intindex]++;
	}
}


void DoDFT8BitTurbo( float * outbins, float * frequencies, int bins, const float * databuffer, int place_in_data_buffer, int size_of_data_buffer, float q, float speedup )
{
	static int is_setup;
	if( !is_setup ) { is_setup = 1; Setup( frequencies, bins ); }
	static int last_place;
	int i;

	for( i = last_place; i != place_in_data_buffer; i = (i+1)%size_of_data_buffer )
	{
		int16_t ifr1 = (int16_t)( ((databuffer[i]) ) * 4095 );
		Turbo8BitRun( ifr1>>5 ); //5 = Actually only feed algorithm numbers from -128 to 127.
	}
	last_place = place_in_data_buffer;

	static int idiv;
	idiv++;
#if 1
	for( i = 0; i < bins; i++ )
	{
		int iss = cossindata[i*2+0]>>FINAL_DECIMATE;
		int isc = cossindata[i*2+1]>>FINAL_DECIMATE;
		int mux = iss * iss + isc * isc;

		if( mux <= 0 ) 
		{
			outbins[i] = 0;
		}
		else
		{
			outbins[i] = sqrt((float)mux)/50.0;

			if( abs( cossindata[i*2+0] ) > 120 || abs( cossindata[i*2+1] ) > 120 )
				printf( "CS OVF %d/%d/%d/%f\n", i, cossindata[i*2+0], cossindata[i*2+1],outbins[i] );

		}
	} 
#endif
}