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decomult: Replace gross hack for banking "dongle" with something likelier

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This commit is contained in:
AJR 2017-08-20 00:45:00 -04:00
parent 93f85a9a45
commit cfaf536cac
2 changed files with 10 additions and 24 deletions
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1
src/mame/includes/decocass.h
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@ -403,6 +403,5 @@ private:
/* dongle type widel: status */
int32_t m_widel_ctrs; /* latched PROM address (E5x0 LSB, E5x1 MSB) */
int32_t m_widel_latch; /* latched enable PROM (1100xxxx written to E5x1) */
uint8_t m_decomult_bank;
};

33
src/mame/machine/decocass.cpp
View File

@ -1037,6 +1037,8 @@ READ8_MEMBER(decocass_widel_state::decocass_widel_r)
{
if (0 == (offset & E5XX_MASK))
{
if (m_widel_latch && !machine().side_effect_disabled())
m_widel_ctrs = (m_widel_ctrs + 0x100) & 0xfffff;
data = m_mcu->upi41_master_r(space,1);
LOG(4,("%10s 6502-PC: %04x decocass_widel_r(%02x): $%02x <- 8041 STATUS\n", space.machine().time().as_string(6), space.device().safe_pcbase(), offset, data));
}
@ -1052,15 +1054,11 @@ READ8_MEMBER(decocass_widel_state::decocass_widel_r)
{
uint8_t *prom = space.machine().root_device().memregion("dongle")->base();
data = prom[m_widel_ctrs | (m_decomult_bank << 16)];
data = prom[m_widel_ctrs];
LOG(3,("%10s 6502-PC: %04x decocass_widel_r(%02x): $%02x '%c' <- PROM[%04x]\n", space.machine().time().as_string(6), space.device().safe_pcbase(), offset, data, (data >= 32) ? data : '.', m_widel_ctrs));
m_widel_ctrs = (m_widel_ctrs + 1) & 0xffff;
if (m_widel_ctrs == 0)
{
m_decomult_bank++;
}
if (!machine().side_effect_disabled())
m_widel_ctrs = (m_widel_ctrs + 1) & 0xfffff;
}
else
{
@ -1086,7 +1084,10 @@ WRITE8_MEMBER(decocass_widel_state::decocass_widel_w)
{
if (1 == m_widel_latch)
{
m_widel_ctrs = data << 8; // clears lower bits
// BIOS follows writes to here by counting out a lot of dummy reads from the
// same location, probably to advance a 74HC4040 or similar counter.
// Counterintuitive though it may seem, the value written is probably just ignored.
m_widel_ctrs &= 0xff;
LOG(3,("%10s 6502-PC: %04x decocass_e5xx_w(%02x): $%02x -> CTRS MSB (%04x)\n", space.machine().time().as_string(6), space.device().safe_pcbase(), offset, data, m_widel_ctrs));
return;
}
@ -1100,7 +1101,7 @@ WRITE8_MEMBER(decocass_widel_state::decocass_widel_w)
{
if (m_widel_latch)
{
m_widel_ctrs = data; // clears upper bits
m_widel_ctrs = (m_widel_ctrs & 0xfff00) | data; // clears upper bits
LOG(3,("%10s 6502-PC: %04x decocass_e5xx_w(%02x): $%02x -> CTRS LSB (%04x)\n", space.machine().time().as_string(6), space.device().safe_pcbase(), offset, data, m_widel_ctrs));
return;
}
@ -1608,18 +1609,6 @@ MACHINE_RESET_MEMBER(decocass_type3_state,cfghtice)
// Note, this is a hack, I can't see where the bank bits actually get written out
// and the MAME disassembly is currently a mess.
READ8_MEMBER(decocass_widel_state::decocass_fbc2_r)
{
if (!machine().side_effect_disabled())
{
uint8_t data = m_maincpu->space(AS_PROGRAM).read_byte(0xb3);
m_decomult_bank = data;
}
return 0xa8;
}
void decocass_widel_state::machine_start()
{
decocass_state::machine_start();
@ -1635,8 +1624,6 @@ void decocass_widel_state::machine_reset()
m_dongle_r = read8_delegate(FUNC(decocass_widel_state::decocass_widel_r),this);
m_dongle_w = write8_delegate(FUNC(decocass_widel_state::decocass_widel_w),this);
m_maincpu->space(AS_PROGRAM).install_read_handler(0xfbc2, 0xfbc2, read8_delegate(FUNC(decocass_widel_state::decocass_fbc2_r),this));
m_decomult_bank = 0;
m_widel_ctrs = 0;
m_widel_latch = 0;
}