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Diffstat (limited to 'src/devices/sound/ymf271.cpp')
-rw-r--r--src/devices/sound/ymf271.cpp31
1 files changed, 28 insertions, 3 deletions
diff --git a/src/devices/sound/ymf271.cpp b/src/devices/sound/ymf271.cpp
index f36cfd83972..c559eef11bc 100644
--- a/src/devices/sound/ymf271.cpp
+++ b/src/devices/sound/ymf271.cpp
@@ -11,7 +11,7 @@
- A/L bit (alternate loop)
- EN and EXT Out bits
- Src B and Src NOTE bits
- - statusreg Busy and End bits
+ - statusreg Busy flag
- timer register 0x11
- ch2/ch3 (4 speakers)
- PFM (FM using external PCM waveform)
@@ -245,6 +245,28 @@ inline bool ymf271_device::check_envelope_end(YMF271Slot *slot)
return false;
}
+// calculate status end disable/enable (Desert War shots relies on this)
+inline void ymf271_device::calculate_status_end(int slotnum, bool state)
+{
+ // guess: don't enable/disable if slot isn't a multiple of 4
+ if(slotnum & 3)
+ return;
+
+ /*
+ bit scheme is kinda twisted
+ status1 Busy End36 End24 End12 End0 ---- TimB TimA
+ status2 End44 End32 End20 End8 End40 End28 End16 End4
+ */
+ uint8_t subbit = slotnum / 12;
+ uint8_t bankbit = ((slotnum % 12) >> 2);
+
+ if(state == false)
+ m_end_status &= ~(1 << (subbit+bankbit*4));
+ else
+ m_end_status |= (1 << (subbit+bankbit*4));
+
+}
+
void ymf271_device::update_envelope(YMF271Slot *slot)
{
switch (slot->env_state)
@@ -450,6 +472,7 @@ void ymf271_device::update_pcm(int slotnum, int32_t *mixp, int length)
if ((slot->stepptr>>16) > slot->endaddr)
{
slot->stepptr = slot->stepptr - ((uint64_t)slot->endaddr<<16) + ((uint64_t)slot->loopaddr<<16);
+ calculate_status_end(slotnum,true);
if ((slot->stepptr>>16) > slot->endaddr)
{
// overflow
@@ -1003,6 +1026,7 @@ void ymf271_device::write_register(int slotnum, int reg, uint8_t data)
slot->active = 1;
calculate_step(slot);
+ calculate_status_end(slotnum,false);
init_envelope(slot);
init_lfo(slot);
slot->feedback_modulation0 = 0;
@@ -1476,11 +1500,11 @@ READ8_MEMBER( ymf271_device::read )
switch (offset & 0xf)
{
case 0x0:
- return m_status;
+ return m_status | ((m_end_status & 0xf) << 3);
case 0x1:
// statusreg 2
- return 0;
+ return m_end_status >> 4;
case 0x2:
{
@@ -1692,6 +1716,7 @@ void ymf271_device::init_state()
save_item(NAME(m_timerB));
save_item(NAME(m_irqstate));
save_item(NAME(m_status));
+ save_item(NAME(m_end_status));
save_item(NAME(m_enable));
save_item(NAME(m_ext_address));
save_item(NAME(m_ext_rw));