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No need for double precision in ADPCM decoder

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This commit is contained in:
Henrik Rydgard 2013-01-25 00:48:25 +01:00
parent 8a32779150
commit 31b73a0b99
2 changed files with 12 additions and 12 deletions
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18
Core/HW/SasAudio.cpp
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@ -20,12 +20,12 @@
#include "../MemMap.h"
#include "SasAudio.h"
static const double f[5][2] =
{ { 0.0, 0.0 },
{ 60.0 / 64.0, 0.0 },
{ 115.0 / 64.0, -52.0 / 64.0 },
{ 98.0 / 64.0, -55.0 / 64.0 },
{ 122.0 / 64.0, -60.0 / 64.0 } };
static const s8 f[5][2] =
{ { 0, 0 },
{ 60, 0 },
{ 115, -52 },
{ 98, -55 },
{ 122, -60 } };
void VagDecoder::Start(u32 data, int vagSize, bool loopEnabled) {
loopEnabled_ = loopEnabled;
@ -59,12 +59,12 @@ void VagDecoder::DecodeBlock(u8 *&readp) {
for (int i = 0; i < 28; i += 2) {
int d = *readp++;
int s = (short)((d & 0xf) << 12);
samples[i] = (double)(s >> shift_factor);
samples[i] = s >> shift_factor;
s = (short)((d & 0xf0) << 8);
samples[i + 1] = (double)(s >> shift_factor);
samples[i + 1] = s >> shift_factor;
}
for (int i = 0; i < 28; i++) {
samples[i] = samples[i] + s_1 * f[predict_nr][0] + s_2 * f[predict_nr][1];
samples[i] = samples[i] + ((s_1 * f[predict_nr][0] + s_2 * f[predict_nr][1]) >> 6);
s_2 = s_1;
s_1 = samples[i];
}

6
Core/HW/SasAudio.h
View file

@ -86,7 +86,7 @@ public:
bool End() const { return end_; }
private:
double samples[28];
int samples[28];
int curSample;
u32 data_;
@ -96,8 +96,8 @@ private:
int numBlocks_;
// rolling state. start at 0, should probably reset to 0 on loops?
double s_1;
double s_2;
int s_1;
int s_2;
bool loopEnabled_;
bool loopAtNextBlock_;