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Diffstat (limited to 'src/devices/sound/ay8910.cpp')
-rw-r--r--src/devices/sound/ay8910.cpp5
1 files changed, 2 insertions, 3 deletions
diff --git a/src/devices/sound/ay8910.cpp b/src/devices/sound/ay8910.cpp
index 6ba9691fc37..8ba53fb8b3f 100644
--- a/src/devices/sound/ay8910.cpp
+++ b/src/devices/sound/ay8910.cpp
@@ -1125,8 +1125,9 @@ void ay8910_device::sound_stream_update(sound_stream &stream, std::vector<read_s
* channels.
*/
m_count_noise = 0;
+ m_prescale_noise ^= 1;
- if (!m_prescale_noise)
+ if (!m_prescale_noise || is_expanded_mode()) // AY8930 noise generator rate is twice compares as compatibility mode
{
/* The Random Number Generator of the 8910 is a 17-bit shift */
/* register. The input to the shift register is bit0 XOR bit3 */
@@ -1135,9 +1136,7 @@ void ay8910_device::sound_stream_update(sound_stream &stream, std::vector<read_s
// TODO : get actually algorithm for AY8930
m_rng ^= (((m_rng & 1) ^ ((m_rng >> 3) & 1)) << 17);
m_rng >>= 1;
- m_prescale_noise = 1;
}
- m_prescale_noise--;
}
for (int chan = 0; chan < NUM_CHANNELS; chan++)