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fidel*: optimize cpu divider (nw)

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This commit is contained in:
hap 2019-03-28 23:29:40 +01:00
parent cc407fe685
commit f51a980e34
2 changed files with 29 additions and 16 deletions
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5
src/mame/includes/fidelbase.h
View File

@ -31,7 +31,6 @@ public:
m_irq_on(*this, "irq_on"),
m_rombank(*this, "rombank"),
m_mainmap(*this, "mainmap"),
m_div_config(*this, "div_config"),
m_speech(*this, "speech"),
m_speech_rom(*this, "speech"),
m_language(*this, "language"),
@ -42,13 +41,14 @@ public:
// in case reset button is directly tied to maincpu reset pin
virtual DECLARE_INPUT_CHANGED_MEMBER(reset_button) { m_maincpu->set_input_line(INPUT_LINE_RESET, newval ? ASSERT_LINE : CLEAR_LINE); }
DECLARE_INPUT_CHANGED_MEMBER(div_changed);
protected:
// devices/pointers
required_device<cpu_device> m_maincpu;
optional_device<timer_device> m_irq_on;
optional_memory_bank m_rombank;
optional_device<address_map_bank_device> m_mainmap;
optional_ioport m_div_config;
optional_device<s14001a_device> m_speech;
optional_region_ptr<u8> m_speech_rom;
optional_region_ptr<u8> m_language;
@ -72,6 +72,7 @@ protected:
void div_set_cpu_freq(offs_t offset);
void div_trampoline(address_map &map);
u16 m_div_status;
ioport_value m_div_config;
virtual void machine_start() override;
virtual void machine_reset() override;

40
src/mame/machine/fidelbase.cpp
View File

@ -55,13 +55,17 @@ void fidelbase_state::machine_start()
save_item(NAME(m_speech_data));
save_item(NAME(m_speech_bank));
save_item(NAME(m_div_status));
save_item(NAME(m_div_config));
}
void fidelbase_state::machine_reset()
{
chessbase_state::machine_reset();
m_div_status = ~0;
// init cpu divider (optional)
ioport_port *inp = ioport("div_config");
if (inp != nullptr)
div_changed(*inp->field(0x03), nullptr, 0, inp->read());
}
@ -101,30 +105,28 @@ READ8_MEMBER(fidelbase_state::cartridge_r)
void fidelbase_state::div_set_cpu_freq(offs_t offset)
{
static const u16 mask = 0x6000;
u16 status = (offset & mask) | m_div_config->read();
if (status != m_div_status && status & 2)
if (offset != m_div_status)
{
// when a13/a14 is high, XTAL goes through divider(s)
// (depending on factory-set jumper, either one or two 7474)
float div = (status & 1) ? 0.25 : 0.5;
m_maincpu->set_clock_scale((offset & mask) ? div : 1.0);
}
m_maincpu->set_clock_scale(offset ? ((m_div_config & 1) ? 0.25 : 0.5) : 1.0);
m_div_status = status;
m_div_status = offset;
}
}
void fidelbase_state::div_trampoline_w(offs_t offset, u8 data)
{
div_set_cpu_freq(offset);
if (m_div_config)
div_set_cpu_freq(offset & 0x6000);
m_mainmap->write8(offset, data);
}
u8 fidelbase_state::div_trampoline_r(offs_t offset)
{
if (!machine().side_effects_disabled())
div_set_cpu_freq(offset);
if (m_div_config && !machine().side_effects_disabled())
div_set_cpu_freq(offset & 0x6000);
return m_mainmap->read8(offset);
}
@ -134,9 +136,19 @@ void fidelbase_state::div_trampoline(address_map &map)
map(0x0000, 0xffff).rw(FUNC(fidelbase_state::div_trampoline_r), FUNC(fidelbase_state::div_trampoline_w));
}
INPUT_CHANGED_MEMBER(fidelbase_state::div_changed)
{
// stop high frequency background timer if cpu divider is disabled
subdevice<timer_device>("dummy_timer")->enable(bool(newval));
m_maincpu->set_clock_scale(1.0);
m_div_status = ~0;
m_div_config = newval;
}
INPUT_PORTS_START( fidel_cpu_div_2 )
PORT_START("div_config") // hardwired, default to /2
PORT_CONFNAME( 0x03, 0x02, "CPU Divider" )
PORT_CONFNAME( 0x03, 0x02, "CPU Divider" ) PORT_CHANGED_MEMBER(DEVICE_SELF, fidelbase_state, div_changed, nullptr)
PORT_CONFSETTING( 0x00, "Disabled" )
PORT_CONFSETTING( 0x02, "2" )
PORT_CONFSETTING( 0x03, "4" )
@ -144,7 +156,7 @@ INPUT_PORTS_END
INPUT_PORTS_START( fidel_cpu_div_4 )
PORT_START("div_config") // hardwired, default to /4
PORT_CONFNAME( 0x03, 0x03, "CPU Divider" )
PORT_CONFNAME( 0x03, 0x03, "CPU Divider" ) PORT_CHANGED_MEMBER(DEVICE_SELF, fidelbase_state, div_changed, nullptr)
PORT_CONFSETTING( 0x00, "Disabled" )
PORT_CONFSETTING( 0x02, "2" )
PORT_CONFSETTING( 0x03, "4" )