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ymz770.cpp: docs update and cosmetics, no actual impact on emulation

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This commit is contained in:
MetalliC 2017-12-29 03:34:49 +02:00
parent 56793ba89d
commit 062c85de0c
1 changed files with 37 additions and 10 deletions
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47
src/devices/sound/ymz770.cpp
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@ -10,9 +10,12 @@
-----
TODO:
- What does channel ATBL mean?
- how triggered SAC (Simple Access Codes) playback ?
- Simple Access mode. SACs is register / data lists same as SEQ. in 770C, when both /SEL and /CS pins goes low - will be run SAC with number set at data bus.
can not be used in CV1K (/SEL pin is NC, internally pulled to VCC), probably not used in PGM2 too.
770:
- sequencer timers and triggers not implemented (seems used in Deathsmiles ending tune)
- sequencer timers implemented but seems unused, presumably because of design flaws or bugs, likely due to lack of automatic adding of sequencer # to register offset.
in result sequences uses very long chains of 32-sample wait commands instead, wasting a lost of ROM space.
- sequencer triggers not implemented, not sure how they works (Deathsmiles ending tune starts sequence with TGST = 01h, likely a bug and don't affect tune playback)
774:
- 4 channel output
- Equalizer
@ -20,12 +23,16 @@ TODO:
- sequencer off trigger (not used in games)
known SPUs in this series:
YMZ770B ???? Capcom medal hardware (alien.cpp), sample format is not AMM, in other parts looks like 770C
YMZ770B AMMSL Capcom medal hardware (alien.cpp), sample format is not AMM, in other parts looks like 770C
YMZ770C AMMS-A Cave CV1000
YMZ773 AMMS2
YMZ771 SSGS3
YMZ773 AMMS2 Cron corp. video slots
YMZ775 AMMS2B
YMZ774 AMMS2C IGS PGM2
YMZ776 AMMS3 uses AM3 sample format (modified Ogg?)
YMZ778 AMMS3S
YMZ779 AMMS3D
YMZ870 AMMS3EX
***************************************************************************/
@ -302,13 +309,16 @@ void ymz770_device::sequencer()
switch (reg)
{
case 0x0f:
for (int ch = 0; ch < 8; ch++) // might be wrong, ie not needed in case of loop
if (sequence.stopchan & (1 << ch))
m_channels[ch].is_playing = false;
if (sequence.loop)
sequence.offset = get_seq_offs(sequence.sequence); // loop sequence
else
sequence.is_playing = false;
break;
case 0x0e:
sequence.delay = 32 - 1;
sequence.delay = sequence.timer * 32 + 32 - 1;
break;
default:
internal_reg_write(reg, data);
@ -408,22 +418,39 @@ void ymz770_device::internal_reg_write(uint8_t reg, uint8_t data)
switch (reg & 0x0f)
{
case 0:
case 0: // SQSN
m_sequences[ch].sequence = data;
break;
case 1:
case 1: // SQON SQLP
if ((data & 6) == 2 || ((data & 6) == 6 && !m_sequences[ch].is_playing)) // both KON bits 1 is "Keep Playing"
{
m_sequences[ch].offset = get_seq_offs(m_sequences[ch].sequence);
m_sequences[ch].delay = 0;
m_sequences[ch].is_playing = true;
}
else if ((data & 6) == 0)
else if ((data & 6) == 0 && m_sequences[ch].is_playing)
{
m_sequences[ch].is_playing = false;
for (int i = 0; i < 8; i++)
if (m_sequences[ch].stopchan & (1 << i))
m_channels[i].is_playing = false;
}
m_sequences[ch].loop = data & 1;
break;
case 2: // TMRH
m_sequences[ch].timer = (m_sequences[ch].timer & 0x00ff) | (data << 8);
break;
case 3: // TMRL
m_sequences[ch].timer = (m_sequences[ch].timer & 0xff00) | data;
break;
case 6: // SQOF
m_sequences[ch].stopchan = data;
break;
//case 4: // TGST "ON trigger playback channel selection bitmask"
//case 5: // TGEN "OFF trigger playback channel selection bitmask"
//case 7: // YMZ770: unused, but CV1K games write 1 here, must be game bugs or YMZ770C datasheet is wrong and have messed 7 and 8 registers ? ; YMZ771: SQOF_SSG
//case 8: // YMZ770: docs said "set to 01h" but CV1K games never write it, see above. ; YMZ771: TEMPO (wait timer speed control)
default:
if (data)
logerror("unimplemented write %02X %02X\n", reg, data);
@ -733,7 +760,7 @@ void ymz774_device::sequencer()
}
break;
case 0xfe: // timer delay
sequence.delay = sequence.timer * 32; // possible needed -1 or +(32-1)
sequence.delay = sequence.timer * 32 + 32 - 1;
break;
case 0xf0:
sequence.bank = data & 1;