feat(savestate): implement complete save state features for CGB and APU

src/Apu/Apu.php

@@ -471,4 +471,44 @@ public function setWaveRam(array $waveRam): void
             $this->channel3->writeWaveRam($i, $waveRam[$i]);
         }
     }
+
+    /**
+     * Get Channel 1 (for savestate serialization).
+     *
+     * @return Channel\Channel1
+     */
+    public function getChannel1(): Channel\Channel1
+    {
+        return $this->channel1;
+    }
+
+    /**
+     * Get Channel 2 (for savestate serialization).
+     *
+     * @return Channel\Channel2
+     */
+    public function getChannel2(): Channel\Channel2
+    {
+        return $this->channel2;
+    }
+
+    /**
+     * Get Channel 3 (for savestate serialization).
+     *
+     * @return Channel\Channel3
+     */
+    public function getChannel3(): Channel\Channel3
+    {
+        return $this->channel3;
+    }
+
+    /**
+     * Get Channel 4 (for savestate serialization).
+     *
+     * @return Channel\Channel4
+     */
+    public function getChannel4(): Channel\Channel4
+    {
+        return $this->channel4;
+    }
 }

src/Apu/Channel/Channel1.php

@@ -294,4 +294,106 @@ public function disable(): void
     {
         $this->enabled = false;
     }
+
+    // Savestate serialization methods
+
+    public function getLengthCounter(): int
+    {
+        return $this->lengthCounter;
+    }
+
+    public function getCurrentVolume(): int
+    {
+        return $this->currentVolume;
+    }
+
+    public function getEnvelopeTimer(): int
+    {
+        return $this->envelopeTimer;
+    }
+
+    public function getFrequencyTimer(): int
+    {
+        return $this->frequencyTimer;
+    }
+
+    public function getDutyPosition(): int
+    {
+        return $this->dutyPosition;
+    }
+
+    public function getEnabled(): bool
+    {
+        return $this->enabled;
+    }
+
+    public function getSweepTimer(): int
+    {
+        return $this->sweepTimer;
+    }
+
+    public function getSweepShadow(): int
+    {
+        return $this->sweepShadow;
+    }
+
+    public function getSweepEnabled(): bool
+    {
+        return $this->sweepEnabled;
+    }
+
+    public function getDacEnabled(): bool
+    {
+        return $this->dacEnabled;
+    }
+
+    public function setLengthCounter(int $value): void
+    {
+        $this->lengthCounter = $value;
+    }
+
+    public function setCurrentVolume(int $value): void
+    {
+        $this->currentVolume = $value;
+    }
+
+    public function setEnvelopeTimer(int $value): void
+    {
+        $this->envelopeTimer = $value;
+    }
+
+    public function setFrequencyTimer(int $value): void
+    {
+        $this->frequencyTimer = $value;
+    }
+
+    public function setDutyPosition(int $value): void
+    {
+        $this->dutyPosition = $value;
+    }
+
+    public function setEnabled(bool $value): void
+    {
+        $this->enabled = $value;
+    }
+
+    public function setSweepTimer(int $value): void
+    {
+        $this->sweepTimer = $value;
+    }
+
+    public function setSweepShadow(int $value): void
+    {
+        $this->sweepShadow = $value;
+    }
+
+    public function setSweepEnabled(bool $value): void
+    {
+        $this->sweepEnabled = $value;
+    }
+
+    public function setDacEnabled(bool $value): void
+    {
+        $this->dacEnabled = $value;
+    }
 }

src/Apu/Channel/Channel2.php

@@ -215,4 +215,76 @@ public function disable(): void
     {
         $this->enabled = false;
     }
+
+    // Savestate serialization methods
+
+    public function getLengthCounter(): int
+    {
+        return $this->lengthCounter;
+    }
+
+    public function getCurrentVolume(): int
+    {
+        return $this->currentVolume;
+    }
+
+    public function getEnvelopeTimer(): int
+    {
+        return $this->envelopeTimer;
+    }
+
+    public function getFrequencyTimer(): int
+    {
+        return $this->frequencyTimer;
+    }
+
+    public function getDutyPosition(): int
+    {
+        return $this->dutyPosition;
+    }
+
+    public function getEnabled(): bool
+    {
+        return $this->enabled;
+    }
+
+    public function getDacEnabled(): bool
+    {
+        return $this->dacEnabled;
+    }
+
+    public function setLengthCounter(int $value): void
+    {
+        $this->lengthCounter = $value;
+    }
+
+    public function setCurrentVolume(int $value): void
+    {
+        $this->currentVolume = $value;
+    }
+
+    public function setEnvelopeTimer(int $value): void
+    {
+        $this->envelopeTimer = $value;
+    }
+
+    public function setFrequencyTimer(int $value): void
+    {
+        $this->frequencyTimer = $value;
+    }
+
+    public function setDutyPosition(int $value): void
+    {
+        $this->dutyPosition = $value;
+    }
+
+    public function setEnabled(bool $value): void
+    {
+        $this->enabled = $value;
+    }
+
+    public function setDacEnabled(bool $value): void
+    {
+        $this->dacEnabled = $value;
+    }
 }

src/Apu/Channel/Channel3.php

@@ -238,4 +238,56 @@ public function disable(): void
     {
         $this->enabled = false;
     }
+
+    // Savestate serialization methods
+
+    public function getLengthCounter(): int
+    {
+        return $this->lengthCounter;
+    }
+
+    public function getFrequencyTimer(): int
+    {
+        return $this->frequencyTimer;
+    }
+
+    public function getSamplePosition(): int
+    {
+        return $this->samplePosition;
+    }
+
+    public function getEnabled(): bool
+    {
+        return $this->enabled;
+    }
+
+    public function getDacEnabled(): bool
+    {
+        return $this->dacEnabled;
+    }
+
+    public function setLengthCounter(int $value): void
+    {
+        $this->lengthCounter = $value;
+    }
+
+    public function setFrequencyTimer(int $value): void
+    {
+        $this->frequencyTimer = $value;
+    }
+
+    public function setSamplePosition(int $value): void
+    {
+        $this->samplePosition = $value;
+    }
+
+    public function setEnabled(bool $value): void
+    {
+        $this->enabled = $value;
+    }
+
+    public function setDacEnabled(bool $value): void
+    {
+        $this->dacEnabled = $value;
+    }
 }

src/Apu/Channel/Channel4.php

@@ -247,4 +247,76 @@ public function disable(): void
     {
         $this->enabled = false;
     }
+
+    // Savestate serialization methods
+
+    public function getLengthCounter(): int
+    {
+        return $this->lengthCounter;
+    }
+
+    public function getCurrentVolume(): int
+    {
+        return $this->currentVolume;
+    }
+
+    public function getEnvelopeTimer(): int
+    {
+        return $this->envelopeTimer;
+    }
+
+    public function getFrequencyTimer(): int
+    {
+        return $this->frequencyTimer;
+    }
+
+    public function getEnabled(): bool
+    {
+        return $this->enabled;
+    }
+
+    public function getDacEnabled(): bool
+    {
+        return $this->dacEnabled;
+    }
+
+    public function getLfsr(): int
+    {
+        return $this->lfsr;
+    }
+
+    public function setLengthCounter(int $value): void
+    {
+        $this->lengthCounter = $value;
+    }
+
+    public function setCurrentVolume(int $value): void
+    {
+        $this->currentVolume = $value;
+    }
+
+    public function setEnvelopeTimer(int $value): void
+    {
+        $this->envelopeTimer = $value;
+    }
+
+    public function setFrequencyTimer(int $value): void
+    {
+        $this->frequencyTimer = $value;
+    }
+
+    public function setEnabled(bool $value): void
+    {
+        $this->enabled = $value;
+    }
+
+    public function setDacEnabled(bool $value): void
+    {
+        $this->dacEnabled = $value;
+    }
+
+    public function setLfsr(int $value): void
+    {
+        $this->lfsr = $value & 0x7FFF; // Keep to 15 bits
+    }
 }