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a2600.c: Reimplemented FE mapper. Fixes decathlon; partial fix for MT05345.

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This commit is contained in:
Wilbert Pol 2013-12-15 19:31:42 +00:00
parent 661d49f28c
commit 5622220a2b
1 changed files with 46 additions and 32 deletions
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78
src/mess/drivers/a2600.c
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@ -55,7 +55,8 @@ public:
m_joy1(*this, CONTROL1_TAG),
m_joy2(*this, CONTROL2_TAG) ,
m_maincpu(*this, "maincpu"),
m_cassette(*this, "cassette") { }
m_cassette(*this, "cassette"),
m_modeFE_trigger_on_next_access(false) { }
dpc_t m_dpc;
memory_region* m_extra_RAM;
@ -77,13 +78,9 @@ public:
UINT16 m_modeSS_last_address;
unsigned m_FVlocked;
UINT16 m_current_screen_height;
int m_FETimer;
direct_update_delegate m_FE_old_opbase_handler;
DECLARE_DIRECT_UPDATE_MEMBER(modeF6_opbase);
DECLARE_DIRECT_UPDATE_MEMBER(modeDPC_opbase_handler);
DECLARE_DIRECT_UPDATE_MEMBER(modeFE_opbase_handler);
DECLARE_READ8_MEMBER(modeF8_switch_r);
DECLARE_READ8_MEMBER(modeFA_switch_r);
DECLARE_READ8_MEMBER(modeF6_switch_r);
@ -115,6 +112,7 @@ public:
DECLARE_WRITE8_MEMBER(modeDPC_w);
DECLARE_READ8_MEMBER(modeFE_switch_r);
DECLARE_WRITE8_MEMBER(modeFE_switch_w);
DECLARE_READ8_MEMBER(modeFE_rom_r);
DECLARE_READ8_MEMBER(current_bank_r);
DECLARE_READ16_MEMBER(a2600_read_input_port);
DECLARE_READ8_MEMBER(a2600_get_databus_contents);
@ -150,7 +148,6 @@ protected:
void mode3E_RAM_switch(UINT16 offset, UINT8 data);
void modeFV_switch(UINT16 offset, UINT8 data);
void modeJVP_switch(UINT16 offset, UINT8 data);
void modeFE_switch(UINT16 offset, UINT8 data);
void install_banks(int count, unsigned init);
UINT8 *m_cart;
@ -169,8 +166,9 @@ protected:
int detect_32K_mode3F();
int detect_super_chip();
unsigned long detect_2600controllers();
required_device<cpu_device> m_maincpu;
required_device<m6502_device> m_maincpu;
required_device<cassette_image_device> m_cassette;
bool m_modeFE_trigger_on_next_access;
};
@ -1205,45 +1203,59 @@ depending on last byte & 0x20 -> 0x00 -> switch to bank #1
*/
DIRECT_UPDATE_MEMBER(a2600_state::modeFE_opbase_handler)
{
/* Still cheating a bit here by looking bit 13 of the address..., but the high byte of the
cpu should be the last byte that was on the data bus and so should determine the bank
we should switch in. */
m_bank_base[1] = memregion("user1")->base() + 0x1000 * ( ( m_maincpu->pc() & 0x2000 ) ? 0 : 1 );
membank("bank1")->set_base(m_bank_base[1] );
/* and restore old opbase handler */
m_maincpu->space(AS_PROGRAM).set_direct_update_handler(m_FE_old_opbase_handler);
return address;
}
void a2600_state::modeFE_switch(UINT16 offset, UINT8 data)
{
address_space& space = m_maincpu->space(AS_PROGRAM);
/* Retrieve last byte read by the cpu (for this mapping scheme this
should be the last byte that was on the data bus
*/
m_FE_old_opbase_handler = space.set_direct_update_handler(direct_update_delegate(FUNC(a2600_state::modeFE_opbase_handler), this));
}
READ8_MEMBER(a2600_state::modeFE_switch_r)
{
UINT8 data = space.read_byte(0xFE + offset );
if ( ! space.debugger_access() )
{
modeFE_switch(offset, 0 );
switch ( offset & 1 )
{
case 0:
/* The next byte on the data bus determines which bank to switch to */
m_modeFE_trigger_on_next_access = true;
break;
case 1:
if ( m_modeFE_trigger_on_next_access ) {
m_bank_base[1] = m_cart + 0x1000 * ( ( data & 0x20 ) ? 0 : 1 );
m_modeFE_trigger_on_next_access = false;
}
break;
}
}
return space.read_byte(0xFE);
return data;
}
WRITE8_MEMBER(a2600_state::modeFE_switch_w)
{
space.write_byte(0xFE, data );
if ( ! space.debugger_access() )
{
modeFE_switch(offset, 0 );
/* The next byte on the data bus determines which bank to switch to */
m_modeFE_trigger_on_next_access = true;
}
}
READ8_MEMBER(a2600_state::modeFE_rom_r)
{
UINT8 data = m_bank_base[1][offset];;
if ( ! space.debugger_access() )
{
if ( m_modeFE_trigger_on_next_access )
{
m_bank_base[1] = m_cart + 0x1000 * ( ( data & 0x20 ) ? 0 : 1 );
m_modeFE_trigger_on_next_access = false;
}
}
return data;
}
READ8_MEMBER(a2600_state::current_bank_r)
{
return m_current_bank;
@ -1799,7 +1811,9 @@ void a2600_state::machine_reset()
case modeFE:
space.install_write_handler(0x01fe, 0x01fe, write8_delegate(FUNC(a2600_state::modeFE_switch_w),this));
space.install_read_handler(0x01fe, 0x01fe, read8_delegate(FUNC(a2600_state::modeFE_switch_r),this));
space.install_read_handler(0x01fe, 0x01ff, read8_delegate(FUNC(a2600_state::modeFE_switch_r),this));
space.install_read_handler(0x1000, 0x1fff, read8_delegate(FUNC(a2600_state::modeFE_rom_r),this));
m_modeFE_trigger_on_next_access = false;
break;
case mode3E: