Use float instead of double

main.cpp

@@ -51,8 +51,8 @@ void sigIntHandler(int sigNum)
 
 int main(int argc, char** argv)
 {
-    double frequency = 100.0;
+    float frequency = 100.f;
-    double bandwidth = 100.0;
+    float bandwidth = 100.f;
     uint16_t dmaChannel = 0;
     bool loop = false;
     std::string filename;

sample.cpp

@@ -35,7 +35,7 @@
 #include <climits>
 
 Sample::Sample(uint8_t *data, uint16_t channels, uint16_t bitsPerChannel)
-    : value(0.)
+    : value(0.f)
 {
     int32_t sum = 0;
     int16_t *channelValues = new int16_t[channels];
@@ -48,25 +48,25 @@ Sample::Sample(uint8_t *data, uint16_t channels, uint16_t bitsPerChannel)
         }
         sum += channelValues[i];
     }
-    value = 2 * sum / channels / static_cast<double>(USHRT_MAX);
+    value = 2 * sum / channels / static_cast<float>(USHRT_MAX);
     delete[] channelValues;
 }
 
-double Sample::getMonoValue()
+float Sample::getMonoValue()
 {
     return value;
 }
 
 #ifndef NO_PREEMP
 PreEmphasis::PreEmphasis(uint32_t sampleRate)
-    : timeConst(sampleRate * 75.0e-6), prevValue(0.)
+    : timeConst(sampleRate * 75.0e-6f), prevValue(0.f)
 {
 }
 
-double PreEmphasis::filter(double value)
+float PreEmphasis::filter(float value)
 {
     prevValue = value;
-    value = value + (prevValue - value) / (1. - timeConst);
+    value = value + (prevValue - value) / (1.f - timeConst);
     return value;
 }
 #endif

sample.hpp

@@ -40,9 +40,9 @@ class Sample
 {
     public:
         Sample(uint8_t *data, uint16_t channels, uint16_t bitsPerChannel);
-        double getMonoValue();
+        float getMonoValue();
     protected:
-        double value;
+        float value;
 };
 
 #ifndef NO_PREEMP
@@ -50,9 +50,9 @@ class PreEmphasis
 {
     public:
         PreEmphasis(uint32_t sampleRate);
-        double filter(double value);
+        float filter(float value);
     protected:
-        double timeConst, prevValue;
+        float timeConst, prevValue;
 };
 #endif
 

transmitter.cpp

@@ -165,7 +165,7 @@ uint32_t Transmitter::getPeripheralsSize()
     return size;
 }
 
-double Transmitter::getSourceFreq()
+float Transmitter::getSourceFreq()
 {
     return (getPeripheralsVirtBaseAddress() == BCM2838_PERI_VIRT_BASE) ? BCM2838_PLLD_FREQ : BCM2835_PLLD_FREQ;
 }
@@ -214,7 +214,7 @@ void Transmitter::freeMemory(AllocatedMemory &memory)
 volatile PWMRegisters *Transmitter::initPwmController()
 {
     volatile ClockRegisters *pwmClk = reinterpret_cast<ClockRegisters *>(getPeripheralVirtAddress(PWMCLK_BASE_OFFSET));
-    double pwmClkFreq = PWM_WRITES_PER_SAMPLE * PWM_CHANNEL_RANGE * sampleRate / 1000000;
+    float pwmClkFreq = PWM_WRITES_PER_SAMPLE * PWM_CHANNEL_RANGE * sampleRate / 1000000;
     pwmClk->ctl = (0x5A << 24) | 0x06;
     usleep(1000);
     pwmClk->div = (0x5A << 24) | static_cast<uint32_t>(getSourceFreq() * (0x01 << 12) / pwmClkFreq);
@@ -270,7 +270,7 @@ void Transmitter::closeClockOutput(volatile ClockRegisters *clock)
     clock->ctl = (0x5A << 24) | 0x06;
 }
 
-void Transmitter::transmit(WaveReader &reader, double frequency, double bandwidth, uint8_t dmaChannel, bool preserveCarrierOnExit)
+void Transmitter::transmit(WaveReader &reader, float frequency, float bandwidth, uint8_t dmaChannel, bool preserveCarrierOnExit)
 {
     if (transmitting) {
         throw std::runtime_error("Cannot play, transmitter already in use");
@@ -283,7 +283,7 @@ void Transmitter::transmit(WaveReader &reader, double frequency, double bandwidt
 
     preserveCarrier = preserveCarrierOnExit;
     clockDivisor = static_cast<uint32_t>(round(getSourceFreq() * (0x01 << 12) / frequency));
-    divisorRange = clockDivisor - static_cast<uint32_t>(round(getSourceFreq() * (0x01 << 12) / (frequency + 0.0005 * bandwidth)));
+    divisorRange = clockDivisor - static_cast<uint32_t>(round(getSourceFreq() * (0x01 << 12) / (frequency + 0.0005f * bandwidth)));
     sampleRate = header.sampleRate;
 
     output = (output != nullptr) ? output : initClockOutput();
@@ -377,7 +377,6 @@ void Transmitter::transmitViaDma(WaveReader &reader, uint32_t bufferSize, uint8_
 
     volatile PWMRegisters *pwm = initPwmController();
 
-    double value;
     uint32_t i, cbOffset = 0;
 #ifndef NO_PREEMP
     PreEmphasis preEmphasis(sampleRate);
@@ -387,7 +386,7 @@ void Transmitter::transmitViaDma(WaveReader &reader, uint32_t bufferSize, uint8_
     volatile uint32_t *clkDiv = reinterpret_cast<uint32_t *>(reinterpret_cast<uint32_t>(dmaCb) + 2 * sizeof(DMAControllBlock) * bufferSize);
     volatile uint32_t *pwmFifoData = reinterpret_cast<uint32_t *>(reinterpret_cast<uint32_t>(clkDiv) + sizeof(uint32_t) * bufferSize);
     for (i = 0; i < bufferSize; i++) {
-        value = samples[i].getMonoValue();
+        float value = samples[i].getMonoValue();
 #ifndef NO_PREEMP
         value = preEmphasis.filter(value);
 #endif
@@ -424,7 +423,7 @@ void Transmitter::transmitViaDma(WaveReader &reader, uint32_t bufferSize, uint8_
             cbOffset = 0;
             eof = samples.size() < bufferSize;
             for (i = 0; i < samples.size(); i++) {
-                value = samples[i].getMonoValue();
+                float value = samples[i].getMonoValue();
 #ifndef NO_PREEMP
                 value = preEmphasis.filter(value);
 #endif
@@ -489,7 +488,7 @@ void Transmitter::transmitThread()
                 break;
             }
             uint32_t prevOffset = offset;
-            double value = samples[offset].getMonoValue();
+            float value = samples[offset].getMonoValue();
 #ifndef NO_PREEMP
             value = preEmphasis.filter(value);
 #endif

transmitter.hpp

@@ -49,13 +49,13 @@ class Transmitter
         Transmitter(const Transmitter &source) = delete;
         Transmitter &operator=(const Transmitter &source) = delete;
         static Transmitter &getInstance();
-        void transmit(WaveReader &reader, double frequency, double bandwidth, uint8_t dmaChannel, bool preserveCarrierOnExit);
+        void transmit(WaveReader &reader, float frequency, float bandwidth, uint8_t dmaChannel, bool preserveCarrierOnExit);
         void stop();
     private:
         Transmitter();
         uint32_t getPeripheralsVirtBaseAddress();
         uint32_t getPeripheralsSize();
-        double getSourceFreq();
+        float getSourceFreq();
         uint32_t getPeripheralPhysAddress(volatile void *object);
         static uint32_t getPeripheralVirtAddress(uint32_t offset);
         uint32_t getMemoryPhysAddress(AllocatedMemory &memory, volatile void *object);