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Improve Namco C352 emulation

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- Change mulaw algorithm to match Namco's Wii VC emulator. This
  appears to be the original algorithm used in the hardware.
- Fix static noise between fights in Tekken 3.
- Fix the order of the phase inversion flags.
This commit is contained in:
superctr 2017-12-08 09:00:28 +01:00
parent 910d2267ca
commit 6637b1d2a9
2 changed files with 30 additions and 13 deletions
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41
src/devices/sound/c352.cpp
View File

@ -74,18 +74,14 @@ void c352_device::fetch_sample(c352_voice_t* v)
}
else
{
int8_t s, s2;
int8_t s;
s = (int8_t)read_byte(v->pos);
v->sample = s<<8;
if(v->flags & C352_FLG_MULAW)
{
s2 = (s&0x7f)>>4;
v->sample = ((s2*s2)<<4) - (~(s2<<1)) * (s&0x0f);
v->sample = (s&0x80) ? (~v->sample)<<5 : v->sample<<5;
}
v->sample = m_mulawtab[s&0xff];
else
v->sample = s<<8;
uint16_t pos = v->pos&0xffff;
@ -184,11 +180,11 @@ void c352_device::sound_stream_update(sound_stream &stream, stream_sample_t **in
// Left
out[0] += (((v->flags & C352_FLG_PHASEFL) ? -s : s) * v->curr_vol[0])>>8;
out[2] += (((v->flags & C352_FLG_PHASEFR) ? -s : s) * v->curr_vol[2])>>8;
out[2] += (((v->flags & C352_FLG_PHASERL) ? -s : s) * v->curr_vol[2])>>8;
// Right
out[1] += (((v->flags & C352_FLG_PHASERL) ? -s : s) * v->curr_vol[1])>>8;
out[3] += (((v->flags & C352_FLG_PHASERL) ? -s : s) * v->curr_vol[3])>>8;
out[1] += (((v->flags & C352_FLG_PHASEFR) ? -s : s) * v->curr_vol[1])>>8;
out[3] += (((v->flags & C352_FLG_PHASEFR) ? -s : s) * v->curr_vol[3])>>8;
}
*buffer_fl++ = (int16_t) (out[0]>>3);
@ -255,7 +251,7 @@ void c352_device::write_reg16(unsigned long address, unsigned short val)
{
for(i=0;i<32;i++)
{
if((m_c352_v[i].flags & C352_FLG_KEYON))
if(m_c352_v[i].flags & C352_FLG_KEYON)
{
m_c352_v[i].pos = (m_c352_v[i].wave_bank<<16) | m_c352_v[i].wave_start;
@ -269,7 +265,7 @@ void c352_device::write_reg16(unsigned long address, unsigned short val)
m_c352_v[i].curr_vol[0] = m_c352_v[i].curr_vol[1] = 0;
m_c352_v[i].curr_vol[2] = m_c352_v[i].curr_vol[3] = 0;
}
else if(m_c352_v[i].flags & C352_FLG_KEYOFF)
if(m_c352_v[i].flags & C352_FLG_KEYOFF)
{
m_c352_v[i].flags &= ~(C352_FLG_BUSY|C352_FLG_KEYOFF);
m_c352_v[i].counter = 0xffff;
@ -295,6 +291,25 @@ void c352_device::device_start()
m_stream = machine().sound().stream_alloc(*this, 0, 4, m_sample_rate_base);
// generate mulaw table (Output similar to namco's VC emulator)
int j = 0;
for(int i=0;i<128;i++)
{
m_mulawtab[i] = j<<5;
if(i < 16)
j += 1;
else if(i < 24)
j += 2;
else if(i < 48)
j += 4;
else if(i < 100)
j += 8;
else
j += 16;
}
for(int i=0;i<128;i++)
m_mulawtab[i+128] = (~m_mulawtab[i])&0xffe0;
// register save state info
for (i = 0; i < 32; i++)
{

2
src/devices/sound/c352.h
View File

@ -105,6 +105,8 @@ private:
int m_divider;
c352_voice_t m_c352_v[32];
int16_t m_mulawtab[256];
uint16_t m_random;
uint16_t m_control; // control flags, purpose unknown.