// license:BSD-3-Clause
// copyright-holders:Valley Bell
// register write:
// 00/01 - ??
// 02/03 - ROM bank (bits 10-13) / loop mode (bits 14-15)
// 04/05 - frequency (2.14 fixed point, 0x4000 = 32000 Hz)
// 06/07 - volume
// 08/09 - sample start address, fraction (2.14 fixed point, i.e. 1 byte = 0x4000)
// 0A/0B - sample start address (high word, i.e. address bits 2..17)
// 0C/0D - sample end address (high word)
// 0E/0F - sample loop address (high word)
// 10/12 - ?? (sometimes value 1F is written)
// 11/13/15/17 - voice enable mask (11 = least significant 8 bits, 17 = most significant 8 bits)
// 19/1B/1D - ?? (written at init time)
// 1A - ??
// 1F - voice select
//
// register read:
// 01 - last sample data (used by main CPU to read sample table from PCM ROM)
// 02/03 - ?? (read after writing to 10/12)
#include "emu.h"
#include "rolandpcm.h"
DEFINE_DEVICE_TYPE(MB87419_MB87420, mb87419_mb87420_device, "mb87419_mb87420", "Roland MB87419/MB87420 PCM")
mb87419_mb87420_device::mb87419_mb87420_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, MB87419_MB87420, tag, owner, clock)
, device_sound_interface(mconfig, *this)
, device_rom_interface(mconfig, *this)
, m_int_callback(*this)
, m_clock(0)
, m_rate(0)
, m_stream(nullptr)
, m_sel_chn(0)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void mb87419_mb87420_device::device_start()
{
m_clock = clock() / 2;
m_rate = m_clock / 512; // usually 32 KHz
m_stream = stream_alloc(0, 2, m_rate);
logerror("Roland PCM: Clock %u, Rate %u\n", m_clock, m_rate);
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void mb87419_mb87420_device::device_reset()
{
m_int_callback(CLEAR_LINE);
}
//-------------------------------------------------
// rom_bank_pre_change - refresh the stream if the
// ROM banking changes
//-------------------------------------------------
void mb87419_mb87420_device::rom_bank_pre_change()
{
// unused right now
m_stream->update();
}
u8 mb87419_mb87420_device::read(offs_t offset)
{
// Note: only offset 0x01 is verified, the rest is probably all wrong
if (offset != 0x01)
logerror("Reading Reg %02X\n", offset);
if (offset < 0x10)
{
pcm_channel& chn = m_chns[m_sel_chn];
switch(offset)
{
case 0x00:
return (chn.mode >> 0) & 0xFF;
case 0x01:
m_stream->update();
{
offs_t addr = (chn.addr >> 14) | ((chn.bank & 0x3C00) << 8);
return read_byte(addr); // return sample data
}
case 0x02: // ROM bank LSB
return (chn.bank >> 0) & 0xFF;
case 0x03: // ROM bank MSB
return (chn.bank >> 8) & 0xFF;
case 0x04: // sample step LSB
return (chn.step >> 0) & 0xFF;
case 0x05: // sample step LSB
return (chn.step >> 8) & 0xFF;
case 0x06: // volume LSB
return (chn.volume >> 0) & 0xFF;
case 0x07: // volume MSB
return (chn.volume >> 8) & 0xFF;
case 0x08: // current address, fraction LSB
return (chn.start >> 0) & 0xFF;
case 0x09: // current address, fraction MSB
return (chn.start >> 8) & 0xFF;
case 0x0A: // current address LSB
return (chn.start >> 16) & 0xFF;
case 0x0B: // current address MSB
return (chn.start >> 24) & 0xFF;
case 0x0C: // sample end address LSB
return (chn.end >> 0) & 0xFF;
case 0x0D: // sample end address MSB
return (chn.end >> 8) & 0xFF;
case 0x0E: // sample loop address LSB
return (chn.loop >> 0) & 0xFF;
case 0x0F: // sample loop address MSB
return (chn.loop >> 8) & 0xFF;
}
}
else
{
switch(offset)
{
case 0x11:
case 0x13:
case 0x15:
case 0x17:
m_stream->update();
{
uint8_t basechn = ((offset >> 1) & 0x03) * 8;
uint8_t result = 0x00;
for (uint8_t ch_id = 0; ch_id < 8; ch_id ++)
result |= (m_chns[basechn + ch_id].enable << ch_id);
return result;
}
break;
case 0x1F:
return m_sel_chn;
}
}
return 0x00;
}
void mb87419_mb87420_device::write(offs_t offset, u8 data)
{
logerror("Reg %02X = %02X\n", offset, data);
if (offset < 0x10)
{
pcm_channel& chn = m_chns[m_sel_chn];
switch(offset)
{
case 0x00:
chn.mode = (chn.mode & 0xFF00) | (data << 0);
break;
case 0x01:
chn.mode = (chn.mode & 0x00FF) | (data << 8);
break;
case 0x02: // ROM bank LSB
chn.bank = (chn.bank & 0xFF00) | (data << 0);
break;
case 0x03: // ROM bank MSB / loop mode
chn.bank = (chn.bank & 0x00FF) | (data << 8);
break;
case 0x04: // sample step LSB
chn.step = (chn.step & 0xFF00) | (data << 0);
break;
case 0x05: // sample step LSB
chn.step = (chn.step & 0x00FF) | (data << 8);
break;
case 0x06: // volume LSB
chn.volume = (chn.volume & 0xFF00) | (data << 0);
break;
case 0x07: // volume MSB
chn.volume = (chn.volume & 0x00FF) | (data << 8);
break;
case 0x08: // current address, fraction LSB
chn.start = (chn.start & 0xFFFFFF00) | (data << 0);
if (chn.enable)
logerror("Roland PCM, channel %u: changing start address while playing!\n", m_sel_chn);
break;
case 0x09: // current address, fraction MSB
chn.start = (chn.start & 0xFFFF00FF) | (data << 8);
if (chn.enable)
logerror("Roland PCM, channel %u: changing start address while playing!\n", m_sel_chn);
break;
case 0x0A: // current address LSB
chn.start = (chn.start & 0xFF00FFFF) | (data << 16);
if (chn.enable)
logerror("Roland PCM, channel %u: changing start address while playing!\n", m_sel_chn);
break;
case 0x0B: // current address MSB
chn.start = (chn.start & 0x00FFFFFF) | (data << 24);
if (chn.enable)
logerror("Roland PCM, channel %u: changing start address while playing!\n", m_sel_chn);
break;
case 0x0C: // sample end address, LSB
chn.end = (chn.end & 0xFF00) | (data << 0);
break;
case 0x0D: // sample end address MSB
chn.end = (chn.end & 0x00FF) | (data << 8);
break;
case 0x0E: // sample loop address LSB
chn.loop = (chn.loop & 0xFF00) | (data << 0);
break;
case 0x0F: // sample loop address MSB
chn.loop = (chn.loop & 0x00FF) | (data << 8);
break;
}
}
else
{
switch(offset)
{
case 0x11:
case 0x13:
case 0x15:
case 0x17:
{
uint8_t basechn = ((offset >> 1) & 0x03) * 8;
for (uint8_t ch_id = 0; ch_id < 8; ch_id ++)
{
pcm_channel& chn = m_chns[basechn + ch_id];
bool play = static_cast<bool>((data >> ch_id) & 1);
if (play && ! chn.enable)
{
chn.addr = chn.start;
offs_t addr = (chn.addr >> 14) | ((chn.bank & 0x3C00) << 8);
chn.smpl_cur = 0;
chn.smpl_nxt = decode_sample((int8_t)read_byte(addr));
chn.play_dir = +1;
logerror("Starting channel %u, bank 0x%04X, addr 0x%05X.%03X\n",
basechn + ch_id, chn.bank, chn.start >> 14, (chn.start & 0x3FFF) << 2);
logerror("Smpl End Ofs: 0x%04X, Loop Ofs 0x%04X, Step 0x%04X, Volume %04X\n",
chn.end << 2, chn.loop << 2, chn.step, chn.volume);
}
chn.enable = play;
}
}
break;
case 0x1F:
m_sel_chn = data & 0x1F;
break;
default:
logerror("Writing unknown reg %02X = %02X\n", offset, data);
break;
}
}
}
//-------------------------------------------------
// sound_stream_update - handle a stream update
//-------------------------------------------------
void mb87419_mb87420_device::sound_stream_update(sound_stream &stream, std::vector<read_stream_view> const &inputs, std::vector<write_stream_view> &outputs)
{
outputs[0].fill(0);
outputs[1].fill(0);
for (auto& chn : m_chns)
{
if (! chn.enable || chn.play_dir == 0)
continue;
for (int smpl = 0; smpl < outputs[0].samples(); smpl ++)
{
s32 smp_data;
if (chn.play_dir > 0)
smp_data = sample_interpolate(chn.smpl_cur, chn.smpl_nxt, chn.addr & 0x3FFF);
else
smp_data = sample_interpolate(chn.smpl_nxt, chn.smpl_cur, chn.addr & 0x3FFF);
smp_data = smp_data * chn.volume;
outputs[0].add_int(smpl, smp_data, 32768 << 14); // >>14 results in a good overall volume
outputs[1].add_int(smpl, smp_data, 32768 << 14);
uint32_t old_addr = chn.addr;
if (chn.play_dir > 0)
chn.addr += chn.step;
else if (chn.play_dir < 0)
chn.addr -= chn.step;
// Note: The sample data is read after incrementing the address, but before handling loop points.
// Reading the sample data after loop point handling breaks the test mode square wave.
// (Sample 0xA7 on the CM-32P.)
if ((chn.addr >> 14) != (old_addr >> 14))
{
offs_t addr = (chn.addr >> 14) | ((chn.bank & 0x3C00) << 8);
//logerror("Chn %u: sample addr 0x%05X.%03X\n", &chn - &m_chns[0], chn.addr >> 14, (chn.addr & 0x3FFF) << 2);
chn.smpl_cur = chn.smpl_nxt;
chn.smpl_nxt += decode_sample((int8_t)read_byte(addr)); // This was verified to be independent from play_dir.
// until the decoding is fixed, we prevent overflow bugs (due to DC offsets when looping) this way
chn.smpl_nxt = std::clamp<int16_t>(chn.smpl_nxt, -0x7FF, +0x7FF);
}
bool reachedEnd = false;
if (chn.play_dir > 0)
{
// This works well with the test mode sine/square wave samples.
if ((chn.addr >> 16) >= chn.end)
reachedEnd = true;
}
else if (chn.play_dir < 0)
{
if ((chn.addr >> 16) < chn.loop)
reachedEnd = true;
}
if (reachedEnd)
{
offs_t oldAddr = chn.addr;
logerror("Chn %u: Sample End at addr 0x%05X.%03X. (Dir %d, Loop Mode %u)\n",
&chn - &m_chns[0], chn.addr >> 14, (chn.addr & 0x3FFF) << 2,
chn.play_dir, chn.bank >> 14);
switch(chn.bank >> 14)
{
case 0: // normal loop
chn.addr = chn.addr + ((chn.loop - chn.end) << 16);
logerror("addr 0x%05X.%03X -> addr 0x%05X.%03X\n",
oldAddr >> 14, (oldAddr & 0x3FFF) << 2,
chn.addr >> 14, (chn.addr & 0x3FFF) << 2);
break;
case 1: // no loop
case 3: // invalid, assume "no loop"
chn.play_dir = 0;
break;
case 2: // ping-pong
// CM-32P samples with ping-pong loop mode:
// 0x00 (low piano note), 0x58..0x67, 0x69..0x6C (choir/strings), 0x9F..0xA4 (brass)
// Note: These formulae are probably incorrect, as they cause some DC offset in most samples.
// Reference sample rate for C5 @ Sample 9F: 34290 Hz.
if (chn.play_dir > 0)
chn.addr = (chn.end << 16) - chn.addr + (chn.end << 16);
else if (chn.play_dir < 0)
chn.addr = (chn.loop << 16) - chn.addr + (chn.loop << 16);
chn.play_dir = -chn.play_dir;
break;
}
if (chn.play_dir == 0)
break;
}
}
}
return;
}
int16_t mb87419_mb87420_device::decode_sample(int8_t data)
{
int16_t val;
int16_t sign;
uint8_t shift;
int16_t result;
if (data < 0)
{
sign = -1;
val = -data;
}
else
{
sign = +1;
val = data;
}
// thanks to Sarayan for figuring out the decoding formula
shift = val >> 4;
val &= 0x0F;
if (! shift)
result = val;
else
result = (0x10 + val) << (shift - 1);
return result * sign;
}
int16_t mb87419_mb87420_device::sample_interpolate(int16_t smp1, int16_t smp2, uint16_t frac)
{
int32_t smpfrac0 = (int32_t)smp1 * (0x4000 - frac);
int32_t smpfrac1 = (int32_t)smp2 * frac;
return (int16_t)((smpfrac0 + smpfrac1) >> 14);
}