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(MESS) a7800.c - Support for >128k cart formats and banked RAM and added bit 4 & bit 5 notes while standardizing 'super' description listing. [Mike Saarna]

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This commit is contained in:
Scott Stone 2014-03-08 19:10:32 +00:00
parent d00673890d
commit 31a8567dfd
2 changed files with 27 additions and 2 deletions
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4
src/mess/drivers/a7800.c
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@ -1095,7 +1095,7 @@ MACHINE_CONFIG_END
***************************************************************************/
ROM_START( a7800 )
ROM_REGION(0x40000, "maincpu", 0)
ROM_REGION(0x100000, "maincpu", 0)
ROM_FILL(0x0000, 0x40000, 0xff)
ROM_SYSTEM_BIOS( 0, "a7800", "Atari 7800" )
ROMX_LOAD("7800.u7", 0xf000, 0x1000, CRC(5d13730c) SHA1(d9d134bb6b36907c615a594cc7688f7bfcef5b43), ROM_BIOS(1))
@ -1104,7 +1104,7 @@ ROM_START( a7800 )
ROM_END
ROM_START( a7800p )
ROM_REGION(0x40000, "maincpu", 0)
ROM_REGION(0x100000, "maincpu", 0)
ROM_FILL(0x0000, 0x40000, 0xff)
ROM_LOAD("7800pal.rom", 0xc000, 0x4000, CRC(d5b61170) SHA1(5a140136a16d1d83e4ff32a19409ca376a8df874))
ROM_END

25
src/mess/machine/a7800.c
View File

@ -128,6 +128,9 @@ void a7800_state::machine_reset()
/* set banks to default states */
memory = m_region_maincpu->base();
if(m_cart_type & 0x20) //supercart bankram
m_bank1->set_base(memory + 0xf0000 );
else
m_bank1->set_base(memory + 0x4000 );
m_bank2->set_base(memory + 0x8000 );
m_bank3->set_base(memory + 0xA000 );
@ -159,6 +162,8 @@ void a7800_state::machine_reset()
bit 1 0x02 - supercart bank switched
bit 2 0x04 - supercart RAM at $4000
bit 3 0x08 - additional state->m_ROM at $4000
bit 4 0x10 - bank 6 at $4000
bit 5 0x20 - supercart banked RAM
bit 8-15 - Special
0 = Normal cart
@ -395,6 +400,13 @@ WRITE8_MEMBER(a7800_state::a7800_cart_w)
{
if(m_cart_type & 0x04)
{
//adjust write location if supercart bankram is in use
if(m_cart_type & 0x20)
{
UINT8 *currentbank1 = (UINT8 *)m_bank1->base();
currentbank1[offset] = data;
}
else
m_ROM[0x4000 + offset] = data;
}
else if(m_cart_type & 0x01)
@ -409,10 +421,23 @@ WRITE8_MEMBER(a7800_state::a7800_cart_w)
if(( m_cart_type & 0x02 ) &&( offset >= 0x4000 ) )
{
/* check if bankram is used */
if( m_cart_type & 0x20 )
{
m_bank1->set_base(memory + 0xf0000+((data & 0x20)<<9));
}
/* fix for 64kb supercart */
if( m_cart_size == 0x10000 )
{
data &= 0x03;
}
else if( m_cart_size == 0x40000 )
{
data &= 0x0f;
}
else if( m_cart_size == 0x80000 )
{
data &= 0x1f;
}
else
{