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casio/pv1000.cpp: Updated sound emulation based on new research. (#11089)

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New functionality is used by Fighting Bug in particular.
This commit is contained in:
David Viens 2023-04-11 12:05:34 -04:00 committed by GitHub
parent d0a2117da4
commit 5b2ab244d1
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1 changed files with 74 additions and 37 deletions
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111
src/mame/casio/pv1000.cpp
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@ -7,9 +7,11 @@
***************************************************************************/
#include "emu.h"
#include "cpu/z80/z80.h"
#include "bus/generic/slot.h"
#include "bus/generic/carts.h"
#include "emupal.h"
#include "screen.h"
#include "softlist_dev.h"
@ -38,11 +40,12 @@ private:
// internal state
struct
{
uint32_t count = 0;
uint32_t count = 0;
uint16_t period = 0;
uint8_t val = 0;
} m_voice[4];
uint8_t val = 1; //boot state of all channels
} m_voice[3];
uint8_t m_ctrl = 0;
sound_stream *m_sh_channel = nullptr;
};
@ -62,25 +65,35 @@ void pv1000_sound_device::device_start()
{
m_sh_channel = stream_alloc(0, 1, clock() / 1024);
save_item(NAME(m_voice[0].count));
save_item(NAME(m_voice[0].period));
save_item(NAME(m_voice[0].val));
save_item(NAME(m_voice[1].count));
save_item(NAME(m_voice[1].period));
save_item(NAME(m_voice[1].val));
save_item(NAME(m_voice[2].count));
save_item(NAME(m_voice[2].period));
save_item(NAME(m_voice[2].val));
// are these ever used?
save_item(NAME(m_voice[3].count));
save_item(NAME(m_voice[3].period));
save_item(NAME(m_voice[3].val));
save_item(STRUCT_MEMBER(m_voice, count));
save_item(STRUCT_MEMBER(m_voice, period));
save_item(STRUCT_MEMBER(m_voice, val));
save_item(NAME(m_ctrl));
}
void pv1000_sound_device::voice_w(offs_t offset, uint8_t data)
{
offset &= 0x03;
m_voice[offset].period = data;
switch (offset)
{
case 0x03:
m_ctrl = data;
break;
default:
{
const uint8_t per = ~data & 0x3f;
if ((per == 0) && (m_voice[offset].period != 0))
{
// flip output once and stall there!
m_voice[offset].val = !m_voice[offset].val;
}
m_voice[offset].period = per;
}
break;
}
}
//-------------------------------------------------
@ -89,40 +102,67 @@ void pv1000_sound_device::voice_w(offs_t offset, uint8_t data)
/*
plgDavid's audio implementation/analysis notes:
plgDavid's audio implementation/analysis notes:
Sound appears to be 3 50/50 pulse voices made by cutting the main clock by 1024,
then by the value of the 6bit period registers.
This creates a surprisingly accurate pitch range.
Sound appears to be 3 50/50 pulse voices made by cutting the main clock by 1024,
then by the value of the 6bit period registers.
This creates a surprisingly accurate pitch range.
Note: the register periods are inverted.
Note: the register periods are inverted.
*/
plgDavid 2023 update: lidnariq (NESDEV) took a fondness to the system and gave me a bunch of test roms
to strenghten the emulation.
Quite a few things were uncovered overall, but for audio specifically:
1)Audio mix/mux control ($FB, case 0x03) was ignored
2)lidnariq's tracing of my PCB scans showed that all three sound outputs are mixed using different volumes:
square1 via i/o$F8 is -6dB, square2 via i/o$F9 is -3dB, defining square3 via i/o$FA as 0dB
*/
void pv1000_sound_device::sound_stream_update(sound_stream &stream, std::vector<read_stream_view> const &inputs, std::vector<write_stream_view> &outputs)
{
auto &buffer = outputs[0];
for (int sampindex = 0; sampindex < buffer.samples(); sampindex++)
//Each channel has a different volume via resistor mixing which correspond to -6dB, -3dB, 0dB drops
static const int volumes[3] = {0x1000, 0x1800, 0x2000};
for (int index = 0; index < buffer.samples(); index++)
{
s32 sum = 0;
// First caltulate all vals
for (int i = 0; i < 3; i++)
{
uint32_t per = (0x3f - (m_voice[i].period & 0x3f));
if (per != 0) //OFF!
sum += m_voice[i].val * 8192;
m_voice[i].count++;
if (m_voice[i].count >= per)
if ((m_voice[i].period > 0) && (m_voice[i].count >= m_voice[i].period))
{
m_voice[i].count = 0;
m_voice[i].val = !m_voice[i].val;
}
}
buffer.put_int(sampindex, sum, 32768);
// Then mix channels according to m_ctrl
if (BIT(m_ctrl, 1))
{
// ch0 and ch1
if (BIT(m_ctrl, 0))
{
const auto xor01 = BIT(m_voice[0].val ^ m_voice[1].val, 0);
const auto xor12 = BIT(m_voice[1].val ^ m_voice[2].val, 0);
sum += xor01 * volumes[0];
sum += xor12 * volumes[1];
}
else
{
sum += m_voice[0].val * volumes[0];
sum += m_voice[1].val * volumes[1];
}
// ch3 is unaffected by m_ctrl bit 1
sum += m_voice[2].val * volumes[2];
}
buffer.put_int(index, sum, 32768);
}
}
@ -212,14 +252,11 @@ void pv1000_state::io_w(offs_t offset, uint8_t data)
case 0x00:
case 0x01:
case 0x02:
case 0x03:
//logerror("io_w offset=%02x, data=%02x (%03d)\n", offset, data , data);
m_sound->voice_w(offset, data);
break;
case 0x03:
//currently unknown use
break;
case 0x05:
m_fd_data = 0xf;
break;
@ -305,8 +342,8 @@ DEVICE_IMAGE_LOAD_MEMBER( pv1000_state::cart_load )
{
uint32_t size = m_cart->common_get_size("rom");
if (size != 0x2000 && size != 0x4000)
return std::make_pair(image_error::INVALIDLENGTH, "Unsupported cartridge size (must be 8K or 16K)");
if (size != 0x2000 && size != 0x4000 && size != 0x8000)
return std::make_pair(image_error::INVALIDLENGTH, "Unsupported cartridge size (must be 8K, 16K or 32K)");
m_cart->rom_alloc(size, GENERIC_ROM8_WIDTH, ENDIANNESS_LITTLE);
m_cart->common_load_rom(m_cart->get_rom_base(), size, "rom");