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slight changes to the rhythm algorithms

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3419
This commit is contained in:
Sebastian Strohhäcker 2009-06-07 19:49:39 +00:00
parent 4ad533c78f
commit 20f226de90
1 changed files with 9 additions and 14 deletions
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23
src/hardware/dbopl.cpp
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@ -32,6 +32,8 @@
//DUNNO Keyon in 4op, switch to 2op without keyoff.
*/
/* $Id: dbopl.cpp,v 1.9 2009-06-07 19:49:39 c2woody Exp $ */
#include <math.h>
#include <stdlib.h>
@ -472,7 +474,7 @@ void Operator::Write20( const Chip* chip, Bit8u val ) {
}
}
void Operator::Write40( const Chip* chip, Bit8u val ) {
void Operator::Write40( const Chip* /*chip*/, Bit8u val ) {
if (!(reg40 ^ val ))
return;
reg40 = val;
@ -809,27 +811,20 @@ INLINE void Channel::GeneratePercussion( Chip* chip, Bit32s* output ) {
//Precalculate stuff used by other outputs
Bit32u noiseBit = (chip->ForwardNoise() & 0x1) << 1;
Bit32u c2 = op2->ForwardWave();
//(bit 7 ^ bit 2) | bit 3 -> combined in bit 1
Bit32u phaseBit = ( (c2 >> 6) ^ ( c2 >> 1 ) ) | ( c2 >> 2 );
Bit32u c4 = op4->ForwardWave();
//bit 5 ^ bit 3 to bit 1
Bit32u gateBit = ( c4 >> 4 ) ^ ( c4 >> 3 );
phaseBit = (phaseBit | gateBit) & 0x2;
Bit32u phaseBit = (((c2 & 0x88) ^ ((c2<<5) & 0x80)) | ((c4 ^ (c4<<2)) & 0x20)) ? 0x02 : 0x00;
//Hi-Hat
Bit32u hhVol = op2->ForwardVolume();
if ( !ENV_SILENT( hhVol ) ) {
/* when phase & 0x200 is set and noise=1 then phase = 0x200|0xd0 */
/* when phase & 0x200 is set and noise=0 then phase = 0x200|(0xd0>>2), ie no change */
Bit32u hhIndex = ( phaseBit << 8 ) | ( 0xd0 >> ( phaseBit ^ noiseBit ) );
Bit32u hhIndex = (phaseBit<<8) | (0x34<<(phaseBit ^ noiseBit));
sample += op2->GetWave( hhIndex, hhVol );
}
//Snare Drum
Operator* op3 = ( this + 1 )->Op(1);
Bit32u sdVol = op3->ForwardVolume();
if ( !ENV_SILENT( sdVol ) ) {
Bit32u sdBits = 0x100 + (c2 & 0x100);
Bit32u sdIndex = sdBits ^ ( noiseBit << 7 );
Bit32u sdIndex = ( 0x100 + (c2 & 0x100) ) ^ ( noiseBit << 7 );
sample += op3->GetWave( sdIndex, sdVol );
}
//Tom-tom
@ -1261,7 +1256,7 @@ void Chip::Setup( Bit32u rate ) {
Bit32s original = (Bit32u)( (AttackSamplesTable[ index ] << shift) / scale);
Bit32s guessAdd = (Bit32u)( scale * (EnvelopeIncreaseTable[ index ] << ( RATE_SH - shift - 3 )));
Bit32s bestAdd;
Bit32s bestAdd = guessAdd;
Bit32u bestDiff = 1 << 30;
for( Bit32u passes = 0; passes < 16; passes ++ ) {
Bit32s volume = ENV_MAX;
@ -1368,7 +1363,7 @@ void InitTables( void ) {
for ( int i = 0; i < 384; i++ ) {
int s = i * 8;
//TODO maybe keep some of the precision errors of the original table?
double val = ( 0.5 + ( pow(2, -1 + ( 255 - s) * ( 1.0 /256 ) )) * ( 1 << MUL_SH ));
double val = ( 0.5 + ( pow(2.0, -1.0 + ( 255 - s) * ( 1.0 /256 ) )) * ( 1 << MUL_SH ));
MulTable[i] = (Bit16u)(val);
}
@ -1379,7 +1374,7 @@ void InitTables( void ) {
}
//Exponential wave
for ( int i = 0; i < 256; i++ ) {
WaveTable[ 0x700 + i ] = (Bit16s)( 0.5 + ( pow(2, -1 + ( 255 - i * 8) * ( 1.0 /256 ) ) ) * 4085 );
WaveTable[ 0x700 + i ] = (Bit16s)( 0.5 + ( pow(2.0, -1.0 + ( 255 - i * 8) * ( 1.0 /256 ) ) ) * 4085 );
WaveTable[ 0x6ff - i ] = -WaveTable[ 0x700 + i ];
}
#endif