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nes: apu: implement "better" mixing scheme (as recommended by nesdev) in the hope of passing some apu_mixer tests. no change in any of the tests, so change backed out (committed as comments only). from what i understand, it's just as likely that the tests are failing to small channel timing problems as mixer problems.

This commit is contained in:
goyuken 2012-12-14 22:29:27 +00:00
parent bab873fa13
commit a9bf3cf58a
1 changed files with 22 additions and 0 deletions
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22
BizHawk.Emulation/Consoles/Nintendo/NES/APU.cs
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@ -1088,6 +1088,25 @@ namespace BizHawk.Emulation.Consoles.Nintendo
int oldmix = 0;
// http://wiki.nesdev.com/w/index.php/APU_Mixer
// in the end, doesn't help pass any tests, so canned
/*
static readonly int[] pulse_table;
static readonly int[] tnd_table;
static APU()
{
const double scale = 43803.0;
pulse_table = new int[31];
tnd_table = new int[203];
pulse_table[0] = tnd_table[0] = 0;
for (int i = 1; i < pulse_table.Length; i++)
pulse_table[i] = (int)Math.Round(scale * 95.52 / (8128.0 / i + 100.0));
for (int i = 1; i < tnd_table.Length; i++)
tnd_table[i] = (int)Math.Round(scale * 163.67 / (24329.0 / i + 100.0));
}
*/
void EmitSample()
{
if (recalculate)
@ -1119,6 +1138,9 @@ namespace BizHawk.Emulation.Consoles.Nintendo
int pulse_out = 376 * (s_pulse0 + s_pulse1);
int tnd_out = 426 * s_tri + 247 * s_noise + 167 * s_dmc;
int mix = pulse_out + tnd_out;
//int pulse_out = pulse_table[s_pulse0 + s_pulse1];
//int tnd_out = tnd_table[3 * s_tri + 2 * s_noise + s_dmc];
//int mix = pulse_out + tnd_out;
dlist.Add(new Delta(sampleclock, mix - oldmix));
oldmix = mix;