PCM DAC: wave interpolation
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@ -42,12 +42,65 @@ void DivPlatformPCMDAC::acquire(short** buf, size_t len) {
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while (chan[0].audSub>=0x10000) {
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chan[0].audSub-=0x10000;
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chan[0].audPos+=((!chan[0].useWave) && chan[0].audDir)?-1:1;
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if (chan[0].audPos>=(int)chan[0].audLen) {
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chan[0].audPos%=chan[0].audLen;
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chan[0].audDir=false;
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}
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chan[0].audDat[0]=chan[0].audDat[1];
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chan[0].audDat[1]=chan[0].audDat[2];
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chan[0].audDat[2]=chan[0].audDat[3];
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chan[0].audDat[3]=chan[0].audDat[4];
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chan[0].audDat[4]=chan[0].audDat[5];
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chan[0].audDat[5]=chan[0].audDat[6];
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chan[0].audDat[6]=chan[0].audDat[7];
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chan[0].audDat[7]=(chan[0].ws.output[chan[0].audPos]-0x80)<<8;
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}
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if (chan[0].audPos>=(int)chan[0].audLen) {
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chan[0].audPos%=chan[0].audLen;
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chan[0].audDir=false;
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const short s0=chan[0].audDat[0];
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const short s1=chan[0].audDat[1];
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const short s2=chan[0].audDat[2];
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const short s3=chan[0].audDat[3];
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const short s4=chan[0].audDat[4];
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const short s5=chan[0].audDat[5];
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const short s6=chan[0].audDat[6];
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const short s7=chan[0].audDat[7];
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switch (interp) {
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case 1: // linear
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output=s6+((s7-s6)*(chan[0].audSub&0xffff)>>16);
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break;
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case 2: { // cubic
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float* cubicTable=DivFilterTables::getCubicTable();
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float* t=&cubicTable[((chan[0].audSub&0xffff)>>6)<<2];
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float result=(float)s4*t[0]+(float)s5*t[1]+(float)s6*t[2]+(float)s7*t[3];
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if (result<-32768) result=-32768;
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if (result>32767) result=32767;
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output=result;
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break;
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}
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case 3: { // sinc
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float* sincTable=DivFilterTables::getSincTable8();
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float* t1=&sincTable[(8191-((chan[0].audSub&0xffff)>>3))<<2];
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float* t2=&sincTable[((chan[0].audSub&0xffff)>>3)<<2];
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float result=(
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s0*t2[3]+
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s1*t2[2]+
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s2*t2[1]+
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s3*t2[0]+
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s4*t1[0]+
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s5*t1[1]+
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s6*t1[2]+
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s7*t1[3]
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);
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if (result<-32768) result=-32768;
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if (result>32767) result=32767;
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output=result;
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break;
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}
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default: // none
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output=s7;
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break;
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}
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output=(chan[0].ws.output[chan[0].audPos]-0x80)<<8;
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} else {
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DivSample* s=parent->getSample(chan[0].sample);
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if (s->samples>0) {
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