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ggm: more accurate addressmap

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hap 2022-11-13 13:42:05 +01:00
parent ef14ef6d24
commit 1adc612884
1 changed files with 34 additions and 20 deletions
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54
src/mame/appliedconcepts/ggm.cpp
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@ -1,6 +1,6 @@
// license:BSD-3-Clause
// copyright-holders:hap
// thanks-to:bataais
// thanks-to:bataais, Berger
/******************************************************************************
Applied Concepts Great Game Machine (GGM), electronic board game computer.
@ -15,6 +15,12 @@ Hardware notes:
Games are on separate cartridges, each came with a keypad overlay.
There were also some standalone machines, eg. Morphy Encore, Odin Encore.
Cartridge pins are A0-A15, D0-D7, external RAM CS and RAM WR.
The opening/endgame cartridges are meant to be ejected/inserted while playing:
switch power switch to MEM (internal RAM gets powered by rechargable battery),
swap cartridge, switch power switch back to ON. In other words, don't power
cycle the machine (or MAME).
Known chess cartridges (*denotes not dumped):
- Chess/Boris 2.5 (aka Sargon 2.5)
@ -25,10 +31,6 @@ Known chess cartridges (*denotes not dumped):
- Steinitz Edition-4 - Master Chess
- *Monitor Edition - Master Kriegspiel
The opening/endgame cartridges are meant to be ejected/inserted while playing:
switch power switch to MEM, swap cartridge, switch power switch back to ON.
In other words, don't power cycle the machine (or MAME).
Other games:
- *Borchek Edition - Master Checkers
- *Odin Edition - Master Reversi
@ -37,11 +39,7 @@ Other games:
- *Lunar Lander (unreleased?)
TODO:
- it doesn't have nvram, it's a workaround for MAME forcing a hard reset when
swapping in a new cartridge
- confirm display AP segment, is it used anywhere?
- verify cartridge pinout, right now assume A0-A15 (max known cart size is 24KB).
Boris/Sargon cartridge is A0-A11 and 2 CS lines, Steinitz uses the whole range.
******************************************************************************/
@ -109,6 +107,8 @@ private:
DECLARE_DEVICE_IMAGE_LOAD_MEMBER(load_cart);
DECLARE_DEVICE_IMAGE_UNLOAD_MEMBER(unload_cart);
u8 extram_r(offs_t offset);
void extram_w(offs_t offset, u8 data);
void select_w(u8 data);
void control_w(u8 data);
u8 input_r();
@ -121,6 +121,7 @@ private:
u8 m_shift_data = 0;
u8 m_shift_clock = 0;
bool m_extram_enabled = false;
u8 m_overlay = 0;
};
@ -175,21 +176,33 @@ DEVICE_IMAGE_LOAD_MEMBER(ggm_state::load_cart)
const char *overlay = image.get_feature("overlay");
m_overlay = overlay ? strtoul(overlay, nullptr, 0) & 0xf : 0;
// extra ram (optional)
if (image.get_feature("ram"))
m_maincpu->space(AS_PROGRAM).install_ram(0x0800, 0x0fff, m_extram);
// external ram (optional)
memset(m_extram, 0, m_extram.bytes());
m_extram_enabled = image.get_feature("ram") != nullptr;
return image_init_result::PASS;
}
DEVICE_IMAGE_UNLOAD_MEMBER(ggm_state::unload_cart)
{
// unmap extra ram
if (image.get_feature("ram"))
{
m_maincpu->space(AS_PROGRAM).nop_readwrite(0x0800, 0x0fff);
memset(m_extram, 0, m_extram.bytes());
}
// reset external ram
memset(m_extram, 0, m_extram.bytes());
m_extram_enabled = false;
}
u8 ggm_state::extram_r(offs_t offset)
{
// A11 = 1, A14 + A15 = 0
if (m_extram_enabled)
return m_extram[offset & 0x7ff];
else
return m_cart->read_rom(offset);
}
void ggm_state::extram_w(offs_t offset, u8 data)
{
if (m_extram_enabled)
m_extram[offset & 0x7ff] = data;
}
@ -258,8 +271,9 @@ void ggm_state::main_map(address_map &map)
{
// external slot has potential bus conflict with RAM/VIA
map(0x0000, 0xffff).r(m_cart, FUNC(generic_slot_device::read_rom));
map(0x0000, 0x07ff).ram().share("nvram");
map(0x8000, 0x800f).m(m_via, FUNC(via6522_device::map));
map(0x0000, 0x3fff).rw(FUNC(ggm_state::extram_r), FUNC(ggm_state::extram_w));
map(0x0000, 0x07ff).mirror(0x3000).ram().share("nvram");
map(0x8000, 0x800f).mirror(0x3ff0).m(m_via, FUNC(via6522_device::map));
}