From 60c1da6a66484ddcf42f07336d51f4aef013b1b6 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Thu, 5 Apr 2018 21:04:46 -0400
Subject: [PATCH] Causes the 6560 to obey `set_sample_volume_range`.
Thereby resolves a clipping issue.
---
Components/6560/6560.cpp | 7 ++++---
Components/6560/6560.hpp | 3 ++-
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/Components/6560/6560.cpp b/Components/6560/6560.cpp
index ffe950b24..8790d50bb 100644
--- a/Components/6560/6560.cpp
+++ b/Components/6560/6560.cpp
@@ -18,7 +18,7 @@ AudioGenerator::AudioGenerator(Concurrency::DeferringAsyncTaskQueue &audio_queue
void AudioGenerator::set_volume(uint8_t volume) {
audio_queue_.defer([=]() {
- volume_ = volume;
+ volume_ = static_cast<int16_t>(volume) * range_multiplier_;
});
}
@@ -114,12 +114,12 @@ void AudioGenerator::get_samples(std::size_t number_of_samples, int16_t *target)
// this sums the output of all three sounds channels plus a DC offset for volume;
// TODO: what's the real ratio of this stuff?
- target[c] = (
+ target[c] = static_cast<int16_t>(
(shift_registers_[0]&1) +
(shift_registers_[1]&1) +
(shift_registers_[2]&1) +
((noise_pattern[shift_registers_[3] >> 3] >> (shift_registers_[3]&7))&(control_registers_[3] >> 7)&1)
- ) * volume_ * 700 + volume_ * 44;
+ ) * volume_ + (volume_ >> 4);
}
}
@@ -133,6 +133,7 @@ void AudioGenerator::skip_samples(std::size_t number_of_samples) {
}
void AudioGenerator::set_sample_volume_range(std::int16_t range) {
+ range_multiplier_ = static_cast<int16_t>(range / 64);
}
#undef shift
diff --git a/Components/6560/6560.hpp b/Components/6560/6560.hpp
index ba461ea38..621c885a2 100644
--- a/Components/6560/6560.hpp
+++ b/Components/6560/6560.hpp
@@ -36,7 +36,8 @@ class AudioGenerator: public ::Outputs::Speaker::SampleSource {
unsigned int counters_[4] = {2, 1, 0, 0}; // create a slight phase offset for the three channels
unsigned int shift_registers_[4] = {0, 0, 0, 0};
uint8_t control_registers_[4] = {0, 0, 0, 0};
- uint8_t volume_ = 0;
+ int16_t volume_ = 0;
+ int16_t range_multiplier_ = 1;
};
/*!