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and this fixes sram access, courtesy of Eke's info. nw.

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This commit is contained in:
Fabio Priuli 2013-02-27 08:02:06 +00:00
parent 1d71a26a9d
commit 4b7ac47224
2 changed files with 19 additions and 36 deletions
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53
src/mess/machine/md_rom.c
View File

@ -1072,50 +1072,33 @@ READ16_MEMBER(md_rom_radica_device::read_a13)
/*-------------------------------------------------
BEGGAR PRINCE
This game uses cart which is the same as SEGA_SRAM
+ bankswitch mechanism to remap some 256K chunk of
ROM and to enable/disable SRAM (not yet fully
emulated)
+ bankswitch mechanism for first 256KB of the image:
depending on bit7 of the value written at 0xe00/2,
accesses to 0x00000-0x3ffff go to the first 256KB
of ROM, or to the second to last 256KB chunk (usually
mapped to 0x380000-0x3bffff). SRAM is mapped at
the end of ROM.
-------------------------------------------------*/
READ16_MEMBER(md_rom_beggarp_device::read)
{
if (m_mode & 2)
{
//000000-03ffff = ROM bank 15 x 256k
//040000-3bffff = ROM banks 2 to 15 x256k
//3c0000-3fffff = ?? SRAM ?? (32k?)
if (offset < 0x040000/2)
return m_rom[offset + 0x380000/2];
else if (offset >= m_nvram_start/2 && offset <= m_nvram_end/2 && m_nvram_active)
return m_nvram[offset & 0x3fff];
else if (offset < 0x400000/2)
return m_rom[offset & 0x1fffff];
}
else
{
// currently not supported
// if (m_mode & 1) //00-40 = unmapped (open bus?)
//00-40 = ROM banks 1 to 16 x256k
if (offset < 0x400000/2)
return m_rom[offset & 0x1fffff];
}
if (offset >= m_nvram_start/2 && offset <= m_nvram_end/2 && m_nvram_active)
return m_nvram[offset & 0x3fff];
if (offset < 0x040000/2)
return m_mode ? m_rom[offset + 0x380000/2] : m_rom[offset];
else if (offset < 0x400000/2)
return m_rom[offset & 0x1fffff];
return 0xffff;
}
WRITE16_MEMBER(md_rom_beggarp_device::write)
{
if (offset >= 0x0e00/2 && offset < 0x0f00/2) // it actually writes to 0xe00/2
{
if (!m_lock)
m_mode = (data & 0xc0) >> 6;
m_lock = BIT(data, 5); // lock bankswitch hardware when set, until hard reset
}
// SRAM is only accessible in mode 2
if (offset >= m_nvram_start/2 && offset <= m_nvram_end/2 && m_nvram_active && !m_nvram_readonly && m_mode == 2)
if (offset >= 0x0e00/2 && offset < 0x0f00/2)
m_mode = BIT(data, 7);
if (offset >= m_nvram_start/2 && offset <= m_nvram_end/2 && m_nvram_active && !m_nvram_readonly)
m_nvram[offset & 0x3fff] = data;
}
@ -1137,7 +1120,7 @@ WRITE16_MEMBER(md_rom_beggarp_device::write_a13)
/*-------------------------------------------------
LEGEND OF WUKONG
This game uses cart which is the same as SEGA_SRAM
+ bankswitch mechanism for last 128k of the image:
+ bankswitch mechanism for last 128KB of the image:
first 2MB of ROM is loaded in 0-0x200000 and
mirrored in 0x200000-0x400000, but depending on
bit7 of the value written at 0xe00/2 accesses to

2
src/mess/machine/md_slot.c
View File

@ -642,7 +642,7 @@ void base_md_cart_slot_device::setup_nvram()
m_cart->m_nvram_handlers_installed = 1;
break;
case BEGGARP:
m_cart->m_nvram_start = 0x3c0000;
m_cart->m_nvram_start = 0x400000;
m_cart->m_nvram_end = m_cart->m_nvram_start + 0xffff;
m_cart->nvram_alloc(machine(), 0x8000); // 32K mirrored
m_cart->m_nvram_active = 1;