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apple2: simplify LC handling even further (nw)

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This commit is contained in:
Peter Ferrie 2017-03-02 21:01:44 -08:00
parent 7e9e3f5b4d
commit a23d008d86
3 changed files with 73 additions and 52 deletions
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60
src/devices/bus/a2bus/ramcard16k.cpp
View File

@ -31,13 +31,13 @@ const device_type A2BUS_RAMCARD16K = device_creator<a2bus_ramcard_device>;
a2bus_ramcard_device::a2bus_ramcard_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, uint32_t clock, const char *shortname, const char *source) :
device_t(mconfig, type, name, tag, owner, clock, shortname, source),
device_a2bus_card_interface(mconfig, *this), m_inh_state(0), m_last_offset(0), m_last_access(0), m_dxxx_bank(0)
device_a2bus_card_interface(mconfig, *this), m_inh_state(0), m_prewrite(false), m_dxxx_bank(0)
{
}
a2bus_ramcard_device::a2bus_ramcard_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
device_t(mconfig, A2BUS_RAMCARD16K, "Apple II 16K Language Card", tag, owner, clock, "a2ram16k", __FILE__),
device_a2bus_card_interface(mconfig, *this), m_inh_state(0), m_last_offset(0), m_last_access(0), m_dxxx_bank(0)
device_a2bus_card_interface(mconfig, *this), m_inh_state(0), m_prewrite(false), m_dxxx_bank(0)
{
}
@ -55,51 +55,63 @@ void a2bus_ramcard_device::device_start()
save_item(NAME(m_inh_state));
save_item(NAME(m_ram));
save_item(NAME(m_dxxx_bank));
save_item(NAME(m_last_offset));
save_item(NAME(m_last_access));
save_item(NAME(m_prewrite));
}
void a2bus_ramcard_device::device_reset()
{
m_inh_state = INH_WRITE;
m_dxxx_bank = 0;
m_last_offset = -1;
m_last_access = 0;
m_prewrite = false;
}
void a2bus_ramcard_device::do_io(int offset, int access)
void a2bus_ramcard_device::do_io(int offset, bool writing)
{
int old_inh_state = m_inh_state;
m_inh_state = INH_NONE;
//any even access disables pre-write and writing
if ((offset & 1) == 0)
{
m_prewrite = false;
m_inh_state &= ~INH_WRITE;
}
//any write disables pre-write
//has no effect on write-enable if writing was enabled already
if (writing == true)
{
m_prewrite = false;
}
//first odd read enables pre-write, second one enables writing
else if ((offset & 1) == 1)
{
if (m_prewrite == false)
{
m_prewrite = true;
}
else
{
m_inh_state |= INH_WRITE;
}
}
switch (offset & 3)
{
case 0:
case 3:
{
m_inh_state = INH_READ;
m_inh_state |= INH_READ;
break;
}
case 3:
{
m_inh_state = INH_READ;
} //fall through
case 1:
case 2:
{
//if accessed twice, then write-enable
if (((m_last_offset & 1) == 1) && (access == m_last_access))
{
m_inh_state |= INH_WRITE;
}
m_inh_state &= ~INH_READ;
break;
}
}
m_last_offset = offset;
m_last_access = access;
m_dxxx_bank = 0;
if (!(offset & 8))
@ -127,7 +139,7 @@ void a2bus_ramcard_device::do_io(int offset, int access)
uint8_t a2bus_ramcard_device::read_c0nx(address_space &space, uint8_t offset)
{
do_io(offset & 0xf, 0);
do_io(offset & 0xf, false);
return 0xff;
}
@ -138,7 +150,7 @@ uint8_t a2bus_ramcard_device::read_c0nx(address_space &space, uint8_t offset)
void a2bus_ramcard_device::write_c0nx(address_space &space, uint8_t offset, uint8_t data)
{
do_io(offset & 0xf, 1);
do_io(offset & 0xf, true);
}
uint8_t a2bus_ramcard_device::read_inh_rom(address_space &space, uint16_t offset)

5
src/devices/bus/a2bus/ramcard16k.h
View File

@ -40,11 +40,10 @@ protected:
virtual int inh_type() override;
private:
void do_io(int offset, int access);
void do_io(int offset, bool writing);
int m_inh_state;
int m_last_offset;
int m_last_access;
bool m_prewrite;
int m_dxxx_bank;
uint8_t m_ram[16*1024];
};

60
src/mame/drivers/apple2e.cpp
View File

@ -369,8 +369,7 @@ private:
bool m_slotc3rom;
bool m_altzp;
bool m_ramrd, m_ramwrt;
bool m_lcram, m_lcram2, m_lcwriteenable;
int m_last_offset, m_last_access;
bool m_lcram, m_lcram2, m_lcprewrite, m_lcwriteenable;
bool m_ioudis;
bool m_romswitch;
bool m_mockingboard4c;
@ -402,7 +401,7 @@ private:
void do_io(address_space &space, int offset, bool is_iic);
uint8_t read_floatingbus();
void update_slotrom_banks();
void lc_update(int offset, int access);
void lc_update(int offset, bool writing);
uint8_t read_slot_rom(address_space &space, int slotbias, int offset);
void write_slot_rom(address_space &space, int slotbias, int offset, uint8_t data);
uint8_t read_int_rom(address_space &space, int slotbias, int offset);
@ -702,9 +701,8 @@ void apple2e_state::machine_start()
save_item(NAME(m_exp_addrmask));
save_item(NAME(m_lcram));
save_item(NAME(m_lcram2));
save_item(NAME(m_lcprewrite));
save_item(NAME(m_lcwriteenable));
save_item(NAME(m_last_offset));
save_item(NAME(m_last_access));
save_item(NAME(m_mockingboard4c));
save_item(NAME(m_intc8rom));
}
@ -760,9 +758,8 @@ void apple2e_state::machine_reset()
// LC default state: read ROM, write enabled, Dxxx bank 2
m_lcram = false;
m_lcram2 = true;
m_lcprewrite = false;
m_lcwriteenable = true;
m_last_offset = -1;
m_last_access = 0;
m_exp_bankhior = 0xf0;
@ -1012,40 +1009,53 @@ void apple2e_state::update_slotrom_banks()
}
}
void apple2e_state::lc_update(int offset, int access)
void apple2e_state::lc_update(int offset, bool writing)
{
bool old_lcram = m_lcram;
m_lcram = false;
m_lcwriteenable = false;
//any even access disables pre-write and writing
if ((offset & 1) == 0)
{
m_lcprewrite = false;
m_lcwriteenable = false;
}
//any write disables pre-write
//has no effect on write-enable if writing was enabled already
if (writing == true)
{
m_lcprewrite = false;
}
//first odd read enables pre-write, second one enables writing
else if ((offset & 1) == 1)
{
if (m_lcprewrite == false)
{
m_lcprewrite = true;
}
else
{
m_lcwriteenable = true;
}
}
switch (offset & 3)
{
case 0:
case 3:
{
m_lcram = true;
break;
}
case 3:
{
m_lcram = true;
} //fall through
case 1:
case 2:
{
//if accessed twice, then write-enable
if (((m_last_offset & 1) == 1) && (access == m_last_access))
{
m_lcwriteenable = true;
}
m_lcram = false;
break;
}
}
m_last_offset = offset;
m_last_access = access;
m_lcram2 = false;
if (!(offset & 8))
@ -1865,7 +1875,7 @@ READ8_MEMBER(apple2e_state::c080_r)
if (slot == 0)
{
lc_update(offset & 0xf, 0);
lc_update(offset & 0xf, false);
}
else
{
@ -1888,7 +1898,7 @@ WRITE8_MEMBER(apple2e_state::c080_w)
if (slot == 0)
{
lc_update(offset & 0xf, 1);
lc_update(offset & 0xf, true);
}
else
{