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-rw-r--r--src/devices/cpu/m6502/gew12.cpp229
1 files changed, 229 insertions, 0 deletions
diff --git a/src/devices/cpu/m6502/gew12.cpp b/src/devices/cpu/m6502/gew12.cpp
new file mode 100644
index 00000000000..4d77abc7771
--- /dev/null
+++ b/src/devices/cpu/m6502/gew12.cpp
@@ -0,0 +1,229 @@
+// license:BSD-3-Clause
+// copyright-holders:Devin Acker
+/***************************************************************************
+
+ gew7.cpp
+
+ Yamaha GEW2 (65c02-based)
+
+***************************************************************************/
+
+#include "emu.h"
+#include "gew12.h"
+
+#include "m6502mcu.ipp"
+
+#include "bus/generic/slot.h"
+
+
+DEFINE_DEVICE_TYPE(GEW12, gew12_device, "gew12", "Yamaha YMW728-F (GEW12)")
+
+gew12_device::gew12_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+ : m6502_mcu_device_base<w65c02_device>(mconfig, GEW12, tag, owner, clock)
+ , device_mixer_interface(mconfig, *this)
+ , m_in_cb(*this, 0xff), m_out_cb(*this)
+ , m_rom(*this, DEVICE_SELF)
+ , m_bank(*this, "bank%u", 0U)
+{
+ program_config.m_internal_map = address_map_constructor(FUNC(gew12_device::internal_map), this);
+}
+
+
+void gew12_device::device_add_mconfig(machine_config &config)
+{
+ // TODO: PCM, UART
+}
+
+void gew12_device::device_start()
+{
+ w65c02_device::device_start();
+
+ m_bank_mask = device_generic_cart_interface::map_non_power_of_two(
+ unsigned(m_rom->bytes() >> 14),
+ [this, base = &m_rom->as_u8()] (unsigned entry, unsigned page)
+ {
+ m_bank[0]->configure_entry(entry, &base[page << 14]);
+ m_bank[1]->configure_entry(entry, &base[page << 14]);
+ });
+
+ m_timer_base[0] = m_timer_base[1] = 0;
+
+ std::fill(std::begin(m_port_data), std::end(m_port_data), 0);
+ std::fill(std::begin(m_port_ddr), std::end(m_port_ddr), 0);
+
+ save_item(NAME(m_irq_pending));
+ save_item(NAME(m_irq_enable));
+ save_item(NAME(m_timer_count));
+ save_item(NAME(m_timer_base));
+ save_item(NAME(m_port_data));
+ save_item(NAME(m_port_ddr));
+}
+
+void gew12_device::device_reset()
+{
+ m6502_mcu_device_base<w65c02_device>::device_reset();
+
+ internal_update();
+ m_irq_pending = 0;
+ m_irq_enable = 0;
+
+ m_timer_count[0] = m_timer_count[1] = 0;
+ internal_update();
+}
+
+
+void gew12_device::internal_map(address_map &map)
+{
+ map(0x0000, 0x07ff).ram();
+
+ // TODO: sound registers
+ map(0x1000, 0x103f).ram();
+
+ map(0x1f00, 0x1f00).rw(FUNC(gew12_device::irq_stat_r), FUNC(gew12_device::irq_en_w));
+ map(0x1f01, 0x1f01).w(FUNC(gew12_device::timer_stat_w));
+
+ // TODO: UART
+ // map(0x1f11, 0x1f11) Rx data
+ // map(0x1f12, 0x1f12) status (bits 0-1: error, bit 2: Rx ready, bit 3: Tx ready)
+ // map(0x1f13, 0x1f13) Tx data
+
+ map(0x1f20, 0x1f23).w(FUNC(gew12_device::timer_count_w));
+ map(0x1f24, 0x1f25).r(FUNC(gew12_device::timer_count_r));
+
+ // TODO - only the last port (PL) is known for sure
+ // on psr160/260, the rest seem to all be handled by built-in key/button scanning
+ map(0x1f2a, 0x1f2f).rw(FUNC(gew12_device::port_r), FUNC(gew12_device::port_w));
+ map(0x1f3a, 0x1f3f).rw(FUNC(gew12_device::port_ddr_r), FUNC(gew12_device::port_ddr_w));
+
+ map(0x1f52, 0x1f52).lw8(NAME([this](uint8_t data) { m_bank[0]->set_entry(data & m_bank_mask); }));
+ map(0x1f53, 0x1f53).nopw(); // bank 0 MSB? (always zero)
+ map(0x1f54, 0x1f54).lw8(NAME([this](uint8_t data) { m_bank[1]->set_entry(data & m_bank_mask); }));
+ map(0x1f55, 0x1f55).nopw(); // bank 1 MSB? (always zero)
+
+ map(0x4000, 0x7fff).bankr(m_bank[0]);
+ map(0x8000, 0xbfff).bankr(m_bank[1]);
+ map(0xc000, 0xffff).rom().region(DEVICE_SELF, 0);
+}
+
+
+void gew12_device::internal_update(u64 current_time)
+{
+ u64 event_time(0U);
+ add_event(event_time, timer_update(0, current_time));
+ add_event(event_time, timer_update(1, current_time));
+ recompute_bcount(event_time);
+}
+
+
+u8 gew12_device::irq_stat_r()
+{
+ internal_update();
+ return m_irq_pending & m_irq_enable;
+}
+
+void gew12_device::irq_en_w(u8 data)
+{
+ internal_update();
+ m_irq_enable = data;
+ irq_update();
+ internal_update();
+}
+
+void gew12_device::internal_irq(int num, int state)
+{
+ if (state == ASSERT_LINE)
+ m_irq_pending |= (1 << num);
+ else
+ m_irq_pending &= ~(1 << num);
+
+ irq_update();
+}
+
+void gew12_device::irq_update()
+{
+ if (m_irq_pending & m_irq_enable)
+ set_input_line(W65C02_IRQ_LINE, ASSERT_LINE);
+ else
+ set_input_line(W65C02_IRQ_LINE, CLEAR_LINE);
+}
+
+
+void gew12_device::timer_stat_w(u8 data)
+{
+ internal_update();
+ if (BIT(data, 0))
+ internal_irq(INTERNAL_IRQ_TIMER0, CLEAR_LINE);
+ if (BIT(data, 1))
+ internal_irq(INTERNAL_IRQ_TIMER1, CLEAR_LINE);
+ internal_update();
+}
+
+u8 gew12_device::timer_count_r(offs_t offset)
+{
+ // both timer IRQ handlers read the current count from the same registers
+ // apparently reading timer 1 count if its IRQ is pending, else timer 0 count
+ internal_update();
+ const unsigned timer = BIT(m_irq_pending, INTERNAL_IRQ_TIMER1);
+
+ if (!BIT(offset, 0))
+ return m_timer_count[timer];
+ else
+ return m_timer_count[timer] >> 8;
+}
+
+void gew12_device::timer_count_w(offs_t offset, u8 data)
+{
+ const unsigned timer = offset >> 1;
+
+ internal_update();
+ if (!BIT(offset, 0))
+ m_timer_count[timer] = (m_timer_count[timer] & 0xff00) | data;
+ else
+ m_timer_count[timer] = (m_timer_count[timer] & 0x00ff) | (data << 8);
+ internal_update();
+}
+
+u64 gew12_device::timer_update(int num, u64 current_time)
+{
+ static constexpr unsigned tick_rate = 48;
+
+ const u64 ticks = current_time / tick_rate;
+ const u64 elapsed = ticks - m_timer_base[num];
+ m_timer_base[num] = ticks;
+
+ // TODO: how are the timers enabled/disabled?
+ // for now, just have 'timer IRQ enable' double as 'timer enable'
+ if (!BIT(m_irq_enable, INTERNAL_IRQ_TIMER0 + num))
+ return 0;
+
+ if (elapsed > m_timer_count[num])
+ internal_irq(INTERNAL_IRQ_TIMER0 + num, ASSERT_LINE);
+
+ m_timer_count[num] -= elapsed;
+
+ return (m_timer_base[num] + m_timer_count[num] + 1) * tick_rate;
+}
+
+
+u8 gew12_device::port_r(offs_t offset)
+{
+ const u8 out_data = m_port_data[offset] & ~m_port_ddr[offset];
+ return out_data | (m_in_cb[offset]() & m_port_ddr[offset]);
+}
+
+void gew12_device::port_w(offs_t offset, u8 data)
+{
+ m_port_data[offset] = data;
+ m_out_cb[offset](0, m_port_data[offset], ~m_port_ddr[offset]);
+}
+
+u8 gew12_device::port_ddr_r(offs_t offset)
+{
+ return m_port_ddr[offset];
+}
+
+void gew12_device::port_ddr_w(offs_t offset, u8 data)
+{
+ m_port_ddr[offset] = data;
+ m_out_cb[offset](0, m_port_data[offset], ~m_port_ddr[offset]);
+}