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Merge pull request #1341 from TomHarte/AYEnvelopePeriod

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Correct envelope period for internal double-resolution.
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Thomas Harte 2024-02-24 15:38:17 -05:00 committed by GitHub
commit 0ee3b628e8
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1 changed files with 5 additions and 5 deletions
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10
Components/AY38910/AY38910.cpp
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@ -127,9 +127,9 @@ void AY38910SampleSource<is_stereo>::advance() {
// Update the noise generator. This recomputes the new bit repeatedly but harmlessly, only shifting
// it into the official 17 upon divider underflow.
if(noise_counter_) noise_counter_--;
if(noise_counter_) --noise_counter_;
else {
noise_counter_ = noise_period_ << 1; // To cover the double resolution of envelopes.
noise_counter_ = noise_period_ << 1; // To cover the double resolution of envelopes.
noise_output_ ^= noise_shift_register_&1;
noise_shift_register_ |= ((noise_shift_register_ ^ (noise_shift_register_ >> 3))&1) << 17;
noise_shift_register_ >>= 1;
@ -137,10 +137,10 @@ void AY38910SampleSource<is_stereo>::advance() {
// Update the envelope generator. Table based for pattern lookup, with a 'refill' step: a way of
// implementing non-repeating patterns by locking them to the final table position.
if(envelope_divider_) envelope_divider_--;
if(envelope_divider_) --envelope_divider_;
else {
envelope_divider_ = envelope_period_;
envelope_position_ ++;
envelope_divider_ = envelope_period_ << 1;
++envelope_position_;
if(envelope_position_ == 64) envelope_position_ = envelope_overflow_masks_[output_registers_[13]];
}