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nec/pc9801.cpp: implement DMA r/w 1MB mask

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This commit is contained in:
angelosa 2023-10-28 20:09:00 +02:00
parent 13192c588e
commit 0e4b21121f
3 changed files with 83 additions and 4 deletions
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57
src/mame/nec/pc9801.cpp
View File

@ -1538,6 +1538,63 @@ void pc9801_state::dma_write_byte(offs_t offset, uint8_t data)
program.write_byte(addr, data);
}
uint8_t pc9801vm_state::dma_read_byte(offs_t offset)
{
address_space &program = m_maincpu->space(AS_PROGRAM);
offs_t addr = (m_dma_offset[m_dack] << 16) | offset;
if (BIT(m_dma_access_ctrl, 2))
addr &= 0xfffff;
if(offset == 0xffff)
{
switch(m_dma_autoinc[m_dack])
{
case 1:
{
uint8_t page = m_dma_offset[m_dack];
m_dma_offset[m_dack] = ((page + 1) & 0xf) | (page & 0xf0);
break;
}
case 3:
m_dma_offset[m_dack]++;
break;
}
}
// logerror("%08x %02x\n",addr, m_dma_access_ctrl);
return program.read_byte(addr);
}
void pc9801vm_state::dma_write_byte(offs_t offset, uint8_t data)
{
address_space &program = m_maincpu->space(AS_PROGRAM);
offs_t addr = (m_dma_offset[m_dack] << 16) | offset;
if (BIT(m_dma_access_ctrl, 2))
addr &= 0xfffff;
if(offset == 0xffff)
{
switch(m_dma_autoinc[m_dack])
{
case 1:
{
uint8_t page = m_dma_offset[m_dack];
m_dma_offset[m_dack] = ((page + 1) & 0xf) | (page & 0xf0);
break;
}
case 3:
m_dma_offset[m_dack]++;
break;
}
}
// logerror("%08x %02x %02x\n",addr,data, m_dma_access_ctrl);
program.write_byte(addr, data);
}
void pc9801_state::set_dma_channel(int channel, int state)
{
if (!state) m_dack = channel;

9
src/mame/nec/pc9801.h
View File

@ -259,6 +259,9 @@ protected:
uint8_t m_dma_autoinc[4];
int m_dack;
virtual uint8_t dma_read_byte(offs_t offset);
virtual void dma_write_byte(offs_t offset, uint8_t data);
private:
void dmapg4_w(offs_t offset, uint8_t data);
@ -266,8 +269,7 @@ private:
void dma_hrq_changed(int state);
void tc_w(int state);
uint8_t dma_read_byte(offs_t offset);
void dma_write_byte(offs_t offset, uint8_t data);
void dack0_w(int state);
void dack1_w(int state);
void dack2_w(int state);
@ -423,6 +425,9 @@ protected:
u8 m_dma_access_ctrl = 0;
u8 m_ide_sel = 0;
virtual uint8_t dma_read_byte(offs_t offset) override;
virtual void dma_write_byte(offs_t offset, uint8_t data) override;
// starting from PC9801VF/U buzzer is substituted with a DAC1BIT
bool m_dac1bit_disable;

21
src/mame/nec/pc_h98.cpp
View File

@ -21,6 +21,10 @@ public:
{}
void pc_h98s(machine_config &config);
protected:
DECLARE_MACHINE_START(pc_h98);
DECLARE_MACHINE_RESET(pc_h98);
};
// TODO: backported from pc9801_epson.cpp, needs mods
@ -123,6 +127,19 @@ static INPUT_PORTS_START( pc_h98 )
PORT_CONFSETTING( 0x04, DEF_STR( No ) )
INPUT_PORTS_END
MACHINE_START_MEMBER(pc_hyper98_state,pc_h98)
{
MACHINE_START_CALL_MEMBER(pc9801bx2);
}
MACHINE_RESET_MEMBER(pc_hyper98_state,pc_h98)
{
MACHINE_RESET_CALL_MEMBER(pc9801bx2);
// boots with DMA > 1MB on.
m_dma_access_ctrl = 0xfb;
}
void pc_hyper98_state::pc_h98s(machine_config &config)
{
pc9801bx2(config);
@ -132,8 +149,8 @@ void pc_hyper98_state::pc_h98s(machine_config &config)
m_maincpu->set_addrmap(AS_IO, &pc_hyper98_state::pc9801bx2_io);
m_maincpu->set_irq_acknowledge_callback("pic8259_master", FUNC(pic8259_device::inta_cb));
MCFG_MACHINE_START_OVERRIDE(pc_hyper98_state, pc9801bx2)
MCFG_MACHINE_RESET_OVERRIDE(pc_hyper98_state, pc9801bx2)
MCFG_MACHINE_START_OVERRIDE(pc_hyper98_state, pc_h98)
MCFG_MACHINE_RESET_OVERRIDE(pc_hyper98_state, pc_h98)
m_ram->set_default_size("14M");
// TODO: extra options, 1.6MB up to 45.6MB