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z8000: Memory access refinements

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- Implement byte smearing for memory and I/O writes
- More accurately handle unaligned word I/O without breaking PCOS-M24
This commit is contained in:
AJR 2020-04-17 23:22:31 -04:00
parent 4a20b56e62
commit c6f3b3be09
2 changed files with 16 additions and 36 deletions
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50
src/devices/cpu/z8000/z8000.cpp
View File

@ -226,7 +226,8 @@ uint32_t z8002_device::RDMEM_L(address_space &space, uint32_t addr)
void z8002_device::WRMEM_B(address_space &space, uint32_t addr, uint8_t value)
{
addr = adjust_addr_for_nonseg_mode(addr);
space.write_byte(addr, value);
uint16_t value16 = value | (value << 8);
space.write_word(addr & ~1, value16, BIT(addr, 0) ? 0x00ff : 0xff00);
}
void z8002_device::WRMEM_W(address_space &space, uint32_t addr, uint16_t value)
@ -246,54 +247,33 @@ void z8002_device::WRMEM_L(address_space &space, uint32_t addr, uint32_t value)
uint8_t z8002_device::RDPORT_B(int mode, uint16_t addr)
{
if(mode == 0)
{
return m_io->read_byte(addr);
}
else
{
/* how to handle MMU reads? for now just do it */
return m_sio->read_byte(addr);
}
address_space &space = (mode == 0) ? *m_io : *m_sio;
return space.read_byte(addr);
}
uint16_t z8002_device::RDPORT_W(int mode, uint16_t addr)
{
if(mode == 0)
{
return m_io->read_word_unaligned((uint16_t)addr);
}
address_space &space = (mode == 0) ? *m_io : *m_sio;
if (BIT(addr, 0))
return swapendian_int16(space.read_word(addr & ~1, 0x00ff));
else
{
/* how to handle MMU reads? */
return m_sio->read_word_unaligned((uint16_t)addr);
}
return space.read_word(addr);
}
void z8002_device::WRPORT_B(int mode, uint16_t addr, uint8_t value)
{
if(mode == 0)
{
m_io->write_byte(addr,value);
}
else
{
/* how to handle MMU writes? for now just do it */
m_sio->write_byte(addr,value);
}
address_space &space = (mode == 0) ? *m_io : *m_sio;
uint16_t value16 = value | (value << 8);
space.write_word(addr & ~1, value16, BIT(addr, 0) ? 0x00ff : 0xff00);
}
void z8002_device::WRPORT_W(int mode, uint16_t addr, uint16_t value)
{
if(mode == 0)
{
m_io->write_word_unaligned((uint16_t)addr, value);
}
address_space &space = (mode == 0) ? *m_io : *m_sio;
if (BIT(addr, 0))
space.write_word(addr & ~1, swapendian_int16(value), 0x00ff);
else
{
/* how to handle MMU writes? */
m_sio->write_word_unaligned((uint16_t)addr, value);
}
space.write_word(addr, value, 0xffff);
}
void z8002_device::cycles(int cycles)

2
src/mame/drivers/m24.cpp
View File

@ -452,7 +452,7 @@ void m24_state::m24_io(address_map &map)
{
map.unmap_value_high();
map(0x0000, 0x000f).rw(m_dmac, FUNC(am9517a_device::read), FUNC(am9517a_device::write));
map(0x0020, 0x0021).mirror(0xc).rw(m_pic, FUNC(pic8259_device::read), FUNC(pic8259_device::write));
map(0x0020, 0x0021).mirror(0xe).rw(m_pic, FUNC(pic8259_device::read), FUNC(pic8259_device::write));
map(0x0040, 0x0043).mirror(0xc).rw(m_pit, FUNC(pit8253_device::read), FUNC(pit8253_device::write));
map(0x0060, 0x0060).rw(FUNC(m24_state::keyboard_data_r), FUNC(m24_state::keyboard_data_w));
map(0x0061, 0x0061).rw(FUNC(m24_state::ctrlport_a_r), FUNC(m24_state::ctrlport_a_w));