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fidel6502: small optimization (nw)

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This commit is contained in:
hap 2018-06-30 18:24:31 +02:00
parent 6c92f7e9ed
commit 95d60edf0a
1 changed files with 35 additions and 6 deletions
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41
src/mame/drivers/fidel6502.cpp
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@ -537,6 +537,7 @@ private:
DECLARE_READ8_MEMBER(div_trampoline_r);
void div_set_cpu_freq(offs_t offset);
void div_trampoline(address_map &map);
u16 m_div_status;
// CSC, SU9, RSC
void csc_prepare_display();
@ -616,9 +617,32 @@ private:
DECLARE_WRITE8_MEMBER(kishon_control_w);
void chesster_map(address_map &map);
void kishon_map(address_map &map);
protected:
virtual void machine_start() override;
virtual void machine_reset() override;
};
// machine start/reset
void fidel6502_state::machine_start()
{
fidelbase_state::machine_start();
// register for savestates
save_item(NAME(m_div_status));
}
void fidel6502_state::machine_reset()
{
fidelbase_state::machine_reset();
m_div_status = ~0;
}
/***************************************************************************
Helper Functions
@ -629,13 +653,18 @@ private:
void fidel6502_state::div_set_cpu_freq(offs_t offset)
{
if (m_div_config->read() & 2)
static const u16 mask = 0x6000;
u16 status = (offset & mask) | m_div_config->read();
if (status != m_div_status && status & 2)
{
// when a13/a14 is high, XTAL goes through divider(s)
// (depending on factory-set jumper, either one or two 7474)
float div = (m_div_config->read() & 1) ? 0.25 : 0.5;
m_maincpu->set_clock_scale((offset & 0x6000) ? div : 1.0);
float div = (status & 1) ? 0.25 : 0.5;
m_maincpu->set_clock_scale((offset & mask) ? div : 1.0);
}
m_div_status = status;
}
WRITE8_MEMBER(fidel6502_state::div_trampoline_w)
@ -709,7 +738,7 @@ void fidel6502_state::su9_set_cpu_freq()
MACHINE_RESET_MEMBER(fidel6502_state, su9)
{
fidelbase_state::machine_reset();
fidel6502_state::machine_reset();
su9_set_cpu_freq();
}
@ -961,7 +990,7 @@ void fidel6502_state::sc9c_set_cpu_freq()
MACHINE_RESET_MEMBER(fidel6502_state, sc9c)
{
fidelbase_state::machine_reset();
fidel6502_state::machine_reset();
sc9c_set_cpu_freq();
}
@ -1206,7 +1235,7 @@ void fidel6502_state::init_fdesdis()
MACHINE_RESET_MEMBER(fidel6502_state, fphantom)
{
fidelbase_state::machine_reset();
fidel6502_state::machine_reset();
m_rombank->set_entry(0);
}