// license:BSD-3-Clause
// copyright-holders:Barry Rodewald
/*
VIA VT82C496G "Green PC" system chipset
*/
#include "emu.h"
#include "vt82c496.h"
/***************************************************************************
IMPLEMENTATION
***************************************************************************/
DEFINE_DEVICE_TYPE(VT82C496, vt82c496_device, "vt82c496", "VIA VT82C496 system chipset")
vt82c496_device::vt82c496_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, VT82C496, tag, owner, clock), m_cpu(*this, finder_base::DUMMY_TAG), m_space(nullptr), m_ram(*this, finder_base::DUMMY_TAG), m_rom(*this, finder_base::DUMMY_TAG), m_reg_select(0)
{
}
void vt82c496_device::device_start()
{
/* get address space we are working on */
m_space = &m_cpu->space(AS_PROGRAM);
save_pointer(m_reg,"Registers",0x100);
}
void vt82c496_device::device_reset()
{
memset(m_reg,0,0x100);
// set up default ROM banking
m_space->install_read_bank(0xc0000,0xc3fff,0,"bios_c0_r");
m_space->install_read_bank(0xc4000,0xc7fff,0,"bios_c4_r");
m_space->install_read_bank(0xc8000,0xcbfff,0,"bios_c8_r");
m_space->install_read_bank(0xcc000,0xcffff,0,"bios_cc_r");
m_space->install_read_bank(0xd0000,0xd3fff,0,"bios_d0_r");
m_space->install_read_bank(0xd4000,0xd7fff,0,"bios_d4_r");
m_space->install_read_bank(0xd8000,0xdbfff,0,"bios_d8_r");
m_space->install_read_bank(0xdc000,0xdffff,0,"bios_dc_r");
m_space->install_read_bank(0xe0000,0xeffff,0,"bios_e0_r");
m_space->install_read_bank(0xf0000,0xfffff,0,"bios_f0_r");
m_space->nop_write(0xc0000,0xfffff);
machine().root_device().membank("bios_c0_r")->set_base(&m_rom[0]);
machine().root_device().membank("bios_c4_r")->set_base(&m_rom[0x4000/4]);
machine().root_device().membank("bios_c8_r")->set_base(&m_rom[0x8000/4]);
machine().root_device().membank("bios_cc_r")->set_base(&m_rom[0xc000/4]);
machine().root_device().membank("bios_d0_r")->set_base(&m_rom[0x10000/4]);
machine().root_device().membank("bios_d4_r")->set_base(&m_rom[0x14000/4]);
machine().root_device().membank("bios_d8_r")->set_base(&m_rom[0x18000/4]);
machine().root_device().membank("bios_dc_r")->set_base(&m_rom[0x1c000/4]);
machine().root_device().membank("bios_e0_r")->set_base(&m_rom[0x20000/4]);
machine().root_device().membank("bios_f0_r")->set_base(&m_rom[0x30000/4]);
}
READ8_MEMBER(vt82c496_device::read)
{
if(offset == 1)
return m_reg[m_reg_select];
return 0x00;
}
WRITE8_MEMBER(vt82c496_device::write)
{
if(offset == 0)
m_reg_select = data;
if(offset == 1)
{
m_reg[m_reg_select] = data;
switch(m_reg_select)
{
case 0x30:
update_mem_c0(data);
break;
case 0x31:
update_mem_d0(data);
break;
case 0x32:
update_mem_e0(data);
break;
}
}
}
void vt82c496_device::update_mem_c0(uint8_t data)
{
if(data & 0x80)
machine().root_device().membank("bios_cc_r")->set_base(m_ram->pointer()+0xcc000);
else
machine().root_device().membank("bios_cc_r")->set_base(&m_rom[0xc000/4]);
if(data & 0x40)
{
m_space->install_write_bank(0xcc000,0xcffff,0,"bios_cc_w");
machine().root_device().membank("bios_cc_w")->set_base(m_ram->pointer()+0xcc000);
}
else
m_space->nop_write(0xcc000,0xcffff);
if(data & 0x20)
machine().root_device().membank("bios_c8_r")->set_base(m_ram->pointer()+0xc8000);
else
machine().root_device().membank("bios_c8_r")->set_base(&m_rom[0x8000/4]);
if(data & 0x10)
{
m_space->install_write_bank(0xc8000,0xcbfff,0,"bios_c8_w");
machine().root_device().membank("bios_c8_w")->set_base(m_ram->pointer()+0xc8000);
}
else
m_space->nop_write(0xc8000,0xcbfff);
if(data & 0x08)
machine().root_device().membank("bios_c4_r")->set_base(m_ram->pointer()+0xc4000);
else
machine().root_device().membank("bios_c4_r")->set_base(&m_rom[0x4000/4]);
if(data & 0x04)
{
m_space->install_write_bank(0xc4000,0xc7fff,0,"bios_c4_w");
machine().root_device().membank("bios_c4_w")->set_base(m_ram->pointer()+0xc4000);
}
else
m_space->nop_write(0xc4000,0xc7fff);
if(data & 0x02)
machine().root_device().membank("bios_c0_r")->set_base(m_ram->pointer()+0xc0000);
else
machine().root_device().membank("bios_c0_r")->set_base(&m_rom[0]);
if(data & 0x01)
{
m_space->install_write_bank(0xc0000,0xc3fff,0,"bios_c0_w");
machine().root_device().membank("bios_c0_w")->set_base(m_ram->pointer()+0xc0000);
}
else
m_space->nop_write(0xc0000,0xc3fff);
}
void vt82c496_device::update_mem_d0(uint8_t data)
{
if(data & 0x80)
machine().root_device().membank("bios_dc_r")->set_base(m_ram->pointer()+0xdc000);
else
machine().root_device().membank("bios_dc_r")->set_base(&m_rom[0x1c000/4]);
if(data & 0x40)
{
m_space->install_write_bank(0xdc000,0xdffff,0,"bios_dc_w");
machine().root_device().membank("bios_dc_w")->set_base(m_ram->pointer()+0xdc000);
}
else
m_space->nop_write(0xdc000,0xdffff);
if(data & 0x20)
machine().root_device().membank("bios_d8_r")->set_base(m_ram->pointer()+0xd8000);
else
machine().root_device().membank("bios_d8_r")->set_base(&m_rom[0x18000/4]);
if(data & 0x10)
{
m_space->install_write_bank(0xd8000,0xdbfff,0,"bios_d8_w");
machine().root_device().membank("bios_d8_w")->set_base(m_ram->pointer()+0xd8000);
}
else
m_space->nop_write(0xd8000,0xdbfff);
if(data & 0x08)
machine().root_device().membank("bios_d4_r")->set_base(m_ram->pointer()+0xd4000);
else
machine().root_device().membank("bios_d4_r")->set_base(&m_rom[0x14000/4]);
if(data & 0x04)
{
m_space->install_write_bank(0xd4000,0xd7fff,0,"bios_d4_w");
machine().root_device().membank("bios_d4_w")->set_base(m_ram->pointer()+0xd4000);
}
else
m_space->nop_write(0xd4000,0xd7fff);
if(data & 0x02)
machine().root_device().membank("bios_d0_r")->set_base(m_ram->pointer()+0xd0000);
else
machine().root_device().membank("bios_d0_r")->set_base(&m_rom[0x10000/4]);
if(data & 0x01)
{
m_space->install_write_bank(0xd0000,0xd3fff,0,"bios_d0_w");
machine().root_device().membank("bios_d0_w")->set_base(m_ram->pointer()+0xd0000);
}
else
m_space->nop_write(0xd0000,0xd3fff);
}
void vt82c496_device::update_mem_e0(uint8_t data)
{
if(data & 0x80)
machine().root_device().membank("bios_e0_r")->set_base(m_ram->pointer()+0xe0000);
else
machine().root_device().membank("bios_e0_r")->set_base(&m_rom[0x20000/4]);
if(data & 0x40)
{
m_space->install_write_bank(0xe0000,0xeffff,0,"bios_e0_w");
machine().root_device().membank("bios_e0_w")->set_base(m_ram->pointer()+0xe0000);
}
else
m_space->nop_write(0xe0000,0xeffff);
if(data & 0x20)
machine().root_device().membank("bios_f0_r")->set_base(m_ram->pointer()+0xf0000);
else
machine().root_device().membank("bios_f0_r")->set_base(&m_rom[0x30000/4]);
if(data & 0x10)
{
m_space->install_write_bank(0xf0000,0xfffff,0,"bios_f0_w");
machine().root_device().membank("bios_f0_w")->set_base(m_ram->pointer()+0xf0000);
}
else
m_space->nop_write(0xf0000,0xfffff);
}