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st2205u: Start pumping data out of the PSG FIFO

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This commit is contained in:
AJR 2020-09-09 15:16:15 -04:00
parent d464d6caeb
commit 27d1ceacbf
2 changed files with 38 additions and 10 deletions
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46
src/devices/cpu/m6502/st2205u.cpp
View File

@ -48,8 +48,10 @@ st2205u_device::st2205u_device(const machine_config &mconfig, const char *tag, d
, m_tien(0)
, m_dac_fifo{{0}}
, m_fifo_filled{0}
, m_fifo_pos{0}
, m_psgc(0)
, m_psgm(0)
, m_psg_on(0)
, m_psg_vol{0}
, m_psg_volm{0}
, m_lbuf(0)
@ -96,8 +98,10 @@ void st2205u_device::device_start()
save_item(NAME(m_tien));
save_item(NAME(m_dac_fifo));
save_item(NAME(m_fifo_filled));
save_item(NAME(m_fifo_pos));
save_item(NAME(m_psgc));
save_item(NAME(m_psgm));
save_item(NAME(m_psg_on));
save_item(NAME(m_psg_vol));
save_item(NAME(m_psg_volm));
save_item(NAME(m_lbuf));
@ -208,8 +212,10 @@ void st2205u_device::device_reset()
m_tien = 0;
std::fill(std::begin(m_fifo_filled), std::end(m_fifo_filled), 0);
std::fill(std::begin(m_fifo_pos), std::end(m_fifo_pos), 0);
m_psgc = 0;
m_psgm = 0;
m_psg_on = 0;
std::fill(std::begin(m_psg_vol), std::end(m_psg_vol), 0);
std::fill(std::begin(m_psg_volm), std::end(m_psg_volm), 0);
@ -407,7 +413,7 @@ void st2205u_device::btc_w(u8 data)
u8 st2205u_device::psg_r(offs_t offset)
{
u8 index = 0;
u8 index = m_fifo_pos[offset >> 1];
if (BIT(offset, 0))
{
bool fwra = m_fifo_filled[offset >> 1] < 8;
@ -421,7 +427,7 @@ void st2205u_device::psg_w(offs_t offset, u8 data)
{
if (m_fifo_filled[offset >> 1] < 16)
{
u8 index = m_fifo_filled[offset >> 1]++;
u8 index = (m_fifo_pos[offset >> 1] + m_fifo_filled[offset >> 1]++) & 15;
m_dac_fifo[offset >> 1][index] = data | (BIT(offset, 0) ? 0x100 : 0);
}
}
@ -434,6 +440,7 @@ u8 st2205u_device::psgc_r()
void st2205u_device::psgc_w(u8 data)
{
m_psgc = data;
m_psg_on &= (data & 0xf0) >> 4;
}
u8 st2205u_device::psgm_r()
@ -500,34 +507,53 @@ u32 st2205u_device::tclk_pres_div(u8 mode) const
TIMER_CALLBACK_MEMBER(st2205u_device::t0_interrupt)
{
m_ireq |= 0x0002;
update_irq_state();
timer_12bit_process(0);
}
TIMER_CALLBACK_MEMBER(st2205u_device::t1_interrupt)
{
m_ireq |= 0x0004;
update_irq_state();
timer_12bit_process(1);
}
TIMER_CALLBACK_MEMBER(st2205u_device::t2_interrupt)
{
m_ireq |= 0x0008;
update_irq_state();
timer_12bit_process(2);
}
TIMER_CALLBACK_MEMBER(st2205u_device::t3_interrupt)
{
m_ireq |= 0x0010;
update_irq_state();
timer_12bit_process(3);
}
void st2205u_device::timer_12bit_process(int t)
{
if (BIT(m_psgc, t + 4))
{
if (BIT(m_psg_on, t))
m_psg_on &= ~(1 << t);
else if (m_fifo_filled[t] != 0)
{
m_psg_on |= 1 << t;
u16 psg_data = m_dac_fifo[t][m_fifo_pos[t]];
if (BIT(m_psgm, 2 * t + 1))
logerror("Playing ADPCM sample %c%02X on channel %d\n", BIT(psg_data, 8) ? '-' : '+', psg_data & 0xff, t);
else
logerror("Playing %s sample %02X on channel %d\n", BIT(m_psgm, 2 * t) ? "tone" : "DAC", psg_data & 0xff, t);
--m_fifo_filled[t];
m_fifo_pos[t] = (m_fifo_pos[t] + 1) & 15;
}
}
// TODO: PCM has its own FIFO
// Timer interrupt is triggered when FIFO has more than 8 empty bytes
if (m_fifo_filled[t] < 8)
{
m_ireq |= 0x0002 << t;
update_irq_state();
}
// Bit 7 of TnCH allows auto-reload
m_count_12bit[t] = BIT(m_tc_12bit[t], 15) ? m_tc_12bit[t] & 0x0fff : 0;

2
src/devices/cpu/m6502/st2205u.h
View File

@ -190,8 +190,10 @@ private:
u8 m_tien;
u16 m_dac_fifo[4][16];
u8 m_fifo_filled[4];
u8 m_fifo_pos[4];
u8 m_psgc;
u8 m_psgm;
u8 m_psg_on;
u8 m_psg_vol[4];
u8 m_psg_volm[2];
u8 m_lbuf;