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osborne1 hack until we can get bank selection working properly

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This commit is contained in:
Vas Crabb 2015-10-28 16:27:36 +11:00
parent a144aa1a51
commit f55f3d9624
2 changed files with 40 additions and 4 deletions
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2
src/mame/drivers/osborne1.c
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@ -38,7 +38,9 @@ used, and the value on the data bus is completley ignored.
03 - Clear BIT 9 signal (map bank 1/2 into F000-FFFF)
TODO:
- Implement ROM/IO bank selection properly
- Implement serial port
- Implement reset key (generates NMI and affects bank selection)
- Verify frequency of the beep/audio alarm.
***************************************************************************/

42
src/mame/machine/osborne1.c
View File

@ -97,6 +97,7 @@ READ8_MEMBER( osborne1_state::osborne1_2000_r )
WRITE8_MEMBER( osborne1_state::osborne1_2000_w )
{
#if 0
/* Check whether regular RAM is enabled */
if ( !m_bank2_enabled || (m_in_irq_handler && m_bankswitch == RAMMODE) )
{
@ -119,6 +120,40 @@ WRITE8_MEMBER( osborne1_state::osborne1_2000_w )
if ( 0xC00 == (offset & 0xC00) ) /* Video PIA */
m_pia1->write(space, offset & 0x03, data);
}
#else
// This code is a nasty hack that doesn't reflect hardware operation,
// but it gets us by while the bank selection implementation is inadequate
if ( ! m_bank2_enabled )
{
m_ram->pointer()[ 0x2000 + offset ] = data;
}
else
{
if ( m_in_irq_handler && m_bankswitch == RAMMODE )
{
m_ram->pointer()[ 0x2000 + offset ] = data;
}
/* Handle writes to the I/O area */
switch( offset & 0x1F00 )
{
case 0x100: /* Floppy */
m_fdc->write(space, offset & 0x03, data);
break;
case 0x400: /* SCREEN-PAC */
m_resolution = data & 0x01;
m_hc_left = (data >> 1) & 0x01;
break;
case 0x900: /* IEEE488 PIA */
m_pia0->write(space, offset & 0x03, data );
break;
case 0xA00: /* Serial */
break;
case 0xC00: /* Video PIA */
m_pia1->write(space, offset & 0x03, data );
break;
}
}
#endif
}
@ -393,9 +428,8 @@ TIMER_CALLBACK_MEMBER(osborne1_state::setup_osborne1)
void osborne1_state::machine_reset()
{
address_space& space = m_maincpu->space(AS_PROGRAM);
/* Initialize memory configuration */
osborne1_bankswitch_w( space, 0x00, 0 );
osborne1_bankswitch_w( m_maincpu->space(AS_IO), 0x00, 0 );
m_pia_0_irq_state = FALSE;
m_pia_1_irq_state = FALSE;
@ -408,6 +442,7 @@ void osborne1_state::machine_reset()
memset( m_ram->pointer() + 0x10000, 0xFF, 0x1000 );
address_space& space = m_maincpu->space(AS_PROGRAM);
space.set_direct_update_handler(direct_update_delegate(FUNC(osborne1_state::osborne1_opbase), this));
}
@ -487,9 +522,8 @@ int osborne1_daisy_device::z80daisy_irq_ack()
osborne1_state *state = machine().driver_data<osborne1_state>();
/* Enable ROM and I/O when IRQ is acknowledged */
UINT8 old_bankswitch = state->m_bankswitch;
address_space& space = state->m_maincpu->space(AS_PROGRAM);
state->osborne1_bankswitch_w( space, 0, 0 );
state->osborne1_bankswitch_w( state->m_maincpu->space(AS_IO), 0, 0 );
state->m_bankswitch = old_bankswitch;
state->m_in_irq_handler = 1;
return 0xF8;