integer player

Author: usrlocalben

app_player_adapter.cpp

@@ -15,8 +15,17 @@ using std::int16_t;
 using std::uint16_t;
 
 namespace rqdq {
-namespace app {
+namespace {
+
+int FP16toS16_fast(int x) {
+	return x >> 1; }
 
+int FP16toS16_slow(int x) {
+	x = std::min(std::max(x, -0xffff), 0xffff);  // clamp
+	return x >> 1; }
+
+}
+namespace app {
 
 void PlayerAdapter::BlasterJmp(void* out, int fmt, int numChannels, int numSamples, void* self) {
 	static_cast<PlayerAdapter*>(self)->BlasterProc(out, fmt, numChannels, numSamples); }
@@ -64,8 +73,8 @@ vga::SetRGB(0, 0x30, 0x20, 0x10);
 	if (numSamples > 0) {
 		player_.Render(pbuf_, pbuf_+4096, numSamples);
 		for (int i=0; i<numSamples; i++) {
-			int l = pbuf_[i] * 32767.0;
-			int r = pbuf_[i+4096] * 32767.0;
+			int l = FP16toS16_fast(pbuf_[i]);
+			int r = FP16toS16_fast(pbuf_[i+4096]);
 			PushBack(l, r); }}
 #ifdef SHOW_TIMING
 vga::SetRGB(0, 0, 0, 0);

app_player_adapter.hpp

@@ -40,7 +40,7 @@ class PlayerAdapter {
 	kb::ModPlayer& player_;
 	alg::RingIndex<4096> rw_;
 	std::int16_t buf_[4096*2];
-	float pbuf_[4096*2]; };
+	int pbuf_[4096*2]; };
 
 
 }  // namespace app

kb_tinymod.cpp

@@ -45,52 +45,55 @@ Paula::Voice::Voice()
 	volume_(0) {}
 
 
-void Paula::Voice::Render(float* buffer, int numSamples) {
+void Paula::Voice::Render(int* buffer, int numSamples) {
 	if (samplePtr_ == NULL) {
 		return; }
 
-	const float gain = (volume_ == 0) ? 0.0f : volume_ / 64.0;
+	int speed = 3546895 / period_ / kOutputFreqInHz * 65536.0f;
 
-	float speed = (3546895 / period_ / kOutputFreqInHz);
 	int8_t* smp = samplePtr_;
 	for (int i=0; i<numSamples; i++) {
-		int p1 = int(pos_);
-		float frac = pos_ - p1;
+		int p1 = pos_>>16;
+		int frac = pos_&0xffff;
 		pos_ += speed;
-		if (pos_ >= sampleLen_) {
-			pos_ -= loopLen_; }
-		int p2 = int(pos_);
-		float smp1 = int8ToFloat(smp[p1]);
-		float smp2 = int8ToFloat(smp[p2]);
-		float cur = smp1*(1.0-frac) + smp2*frac;
+		if (pos_ >= sampleLen_<<16) {
+			pos_ -= loopLen_<<16; }
+		int p2 = pos_>>16;
+		int smp1 = smp[p1];
+		int smp2 = smp[p2];
 
-		buffer[i] += cur * gain; }}
+		// int cur = smp1 * 65536;  // cur is 16:16 [-128, 127]
+		int s = smp1*(0x10000-frac) + smp2*frac;
+		s = s*volume_ >> 6;  // s is unchanged
+		s = s >> 7;          // s is 16:16 [-1,   1]
+		buffer[i] += s; }}
 
 
 void Paula::Voice::Trigger(int8_t* samplePtr, int sampleLen, int loopLen, int offs) {
 	samplePtr_ = samplePtr;
 	sampleLen_ = sampleLen;
 	loopLen_ = loopLen;
-	pos_ = std::min(offs, sampleLen-1); }
+	pos_ = std::min(offs, sampleLen-1) << 16; }
 
 
-Paula::Paula() :masterGain_(0.5f) {}
+Paula::Paula() :masterGain_(0.25f) {}
 
 
-void Paula::Render(float* lb, float* rb, int numSamples) {
+void Paula::Render(int* lb, int* rb, int numSamples) {
 	// const float pan = 0.5f + 0.5f * masterSeparation_;
 	// const float vm0 = masterGain_ * sqrt(pan);
 	// const float vm1 = masterGain_ * sqrt(1-pan);
+	const int mg = masterGain_ * 65536.0f;
 
 	for (int i=0; i<numSamples; i++) {
 		out_[i] = 0;
 		out_[i+4096] = 0; }
 	for (int vi=0; vi<kNumVoices; vi++) {
-		float* dst = (vi==1||vi==2) ? out_ + 4096 : out_;
+		int* dst = (vi==1||vi==2) ? out_ + 4096 : out_;
 		voice_[vi].Render(dst, numSamples); }
 	for (int s=0; s<numSamples; s++) {
-		*lb++ = out_[s]      * masterGain_;
-		*rb++ = out_[s+4096] * masterGain_; }}
+		*lb++ = out_[s]     *mg >> 16;
+		*rb++ = out_[s+4096]*mg >> 16; }}
 
 
 void ModPlayer::Sample::Prepare() {
@@ -439,7 +442,7 @@ ModPlayer::ModPlayer(Paula* p, uint8_t* moddata) :paula_(p) {
 	Reset(); }
 
 
-void ModPlayer::Render(float* lb, float* rb, int numSamples) {
+void ModPlayer::Render(int* lb, int* rb, int numSamples) {
 	while (numSamples) {
 		int todo = std::min(numSamples, trCounter_);
 		if (todo) {
@@ -453,7 +456,7 @@ void ModPlayer::Render(float* lb, float* rb, int numSamples) {
 			trCounter_ = tickRate_; }}}
 
 
-void ModPlayer::RenderJmp(void* param, float* lb, float *rb, int len) {
+void ModPlayer::RenderJmp(void* param, int* lb, int* rb, int len) {
 	((ModPlayer*)param)->Render(lb, rb, len); }
 
 

kb_tinymod.hpp

@@ -9,25 +9,25 @@ class Paula {
 
 	class Voice {
 	public:
-		float pos_;
+		int pos_;  // 16:16 fixed
 		std::int8_t* samplePtr_;
 		int sampleLen_;
 		int loopLen_;
 		int period_;  // 124 .. 65535
 		int volume_;  // 0 .. 64
 
 		Voice();
-		void Render(float* buffer, int numSamples);
+		void Render(int* buffer, int numSamples);
 		void Trigger(std::int8_t* samplePtr, int sampleLen, int loopLen, int offs=0); };
 
 	Voice voice_[4];
-	float out_[4096*2];  // left, right
+	int out_[4096*2];  // left, right
 	float masterGain_;
 	// float masterSeparation_;
 
 public:
 	Paula();
-	void Render(float* lb, float *rb, int numSamples); };
+	void Render(int* lb, int* rb, int numSamples); };
 
 
 class ModPlayer {
@@ -113,12 +113,12 @@ class ModPlayer {
 	char name_[21];
 
 	ModPlayer(Paula* paula, std::uint8_t* moddata);
-	void Render(float* lb, float* rb, int numSamples);
+	void Render(int* lb, int* rb, int numSamples);
 	int GetCurrentPos() const {
 		return curPos_; }
 	int GetCurrentRow() const {
 		return curRow_; }
-	static void RenderJmp(void* param, float* lb, float* rb, int len); };
+	static void RenderJmp(void* param, int* lb, int* rb, int len); };
 
 
 }  // namespace kb