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snes_snd.cpp: TnDIV divides by 256 when setting written is 0 [Angelo Salese]

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This commit is contained in:
angelosa 2018-01-14 04:46:14 +01:00
parent 84e516a892
commit 7a35ee6cf4
2 changed files with 18 additions and 14 deletions
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30
src/mame/audio/snes_snd.cpp
View File

@ -170,6 +170,7 @@ snes_sound_device::snes_sound_device(const machine_config &mconfig, const char *
void snes_sound_device::device_start()
{
const int timerHz[3] = { 8000, 8000, 64000 };
m_channel = machine().sound().stream_alloc(*this, 0, 2, 32000);
m_ram = make_unique_clear<uint8_t[]>(SNES_SPCRAM_SIZE);
@ -178,16 +179,14 @@ void snes_sound_device::device_start()
memcpy(m_ipl_region, machine().root_device().memregion("sound_ipl")->base(), 64);
/* Initialize the timers */
m_timer[0] = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(snes_sound_device::spc_timer),this));
m_timer[0]->adjust(attotime::from_hz(8000), 0, attotime::from_hz(8000));
m_timer[0]->enable(false);
m_timer[1] = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(snes_sound_device::spc_timer),this));
m_timer[1]->adjust(attotime::from_hz(8000), 1, attotime::from_hz(8000));
m_timer[1]->enable(false);
m_timer[2] = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(snes_sound_device::spc_timer),this));
m_timer[2]->adjust(attotime::from_hz(64000), 2, attotime::from_hz(64000));
m_timer[2]->enable(false);
for(int timerNumber=0;timerNumber<3;timerNumber++)
{
m_timer[timerNumber] = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(snes_sound_device::spc_timer),this));
m_timer[timerNumber]->adjust(attotime::from_hz(timerHz[timerNumber]), 0, attotime::from_hz(timerHz[timerNumber]));
m_timer[timerNumber]->enable(false);
m_TnDIV[timerNumber] = 256;
}
state_register();
save_pointer(NAME(m_ram.get()), SNES_SPCRAM_SIZE);
}
@ -991,9 +990,9 @@ int snes_sound_device::advance_envelope( int v )
TIMER_CALLBACK_MEMBER( snes_sound_device::spc_timer )
{
int which = param;
m_counter[which]++;
if (m_counter[which] >= m_ram[0xfa + which] ) // minus =
if (m_counter[which] >= m_TnDIV[which] ) // minus =
{
m_counter[which] = 0;
m_ram[0xfd + which]++;
@ -1139,8 +1138,11 @@ WRITE8_MEMBER( snes_sound_device::spc_io_w )
case 0xa: /* Timer 0 */
case 0xb: /* Timer 1 */
case 0xc: /* Timer 2 */
if (data == 0)
data = 255;
// if 0 then TnDiv is divided by 256, otherwise it's divided by 1 to 255
if(data == 0)
m_TnDIV[offset - 0xa] = 256;
else
m_TnDIV[offset - 0xa] = data;
break;
case 0xd: /* Counter 0 */
case 0xe: /* Counter 1 */

2
src/mame/audio/snes_snd.h
View File

@ -118,6 +118,8 @@ private:
/* IO ports */
uint8_t m_port_in[4]; /* SPC input ports */
uint8_t m_port_out[4]; /* SPC output ports */
uint16_t m_TnDIV[3]; /**< Timer N Divider */
};
DECLARE_DEVICE_TYPE(SNES, snes_sound_device)