问编译器优化如何加快简单操作之间的时间？

EN

{
    SPI m_spiPort();
    m_spiPort.Init();

    m_spiPort.WriteCommand(SLEEPOUT);

    // Color Interface Pixel Format (command 0x3A)
    m_spiPort.WriteCommand(COLMOD);
    m_spiPort.WriteData(0x03); // 0x03 = 12 bits-per-pixel

    // Memory access controller (command 0x36)
    m_spiPort.WriteCommand(MADCTL);
    m_spiPort.WriteData(0x00);

    // Write contrast (command 0x25)
    m_spiPort.WriteCommand(SETCON);
    m_spiPort.WriteData(0x39); // contrast 0x30

    // Display On (command 0x29)
    m_spiPort.WriteCommand(DISPON);

}

class SPI {
public:
    void Init();
    void WriteCommand(unsigned int command);
    void WriteData(unsigned int data);
private:
    void Write(unsigned int value);
};

void SPI::WriteCommand(unsigned int command)
{
    command &= ~0x100;   //clear bit 8
    Write(command);
}

void SPI::WriteData(unsigned int data)
{
    data |= 0x100;   //set bit 8
    Write(data);
}

void SPI::Write(unsigned int value)
{
    LPC_SSP->DR = value;
}
void SPI::Init( void )
{
  LPC_SYSCON->SYSAHBCLKCTRL |= (1<<11);  //Enables clock for SPI
  LPC_SYSCON->SSPCLKDIV = 0x01;

  LPC_IOCON->PIO0_14 &= ~(0x7); // SCK
  LPC_IOCON->PIO0_14 |= 0x2;

  LPC_IOCON->PIO0_17 &= ~(0x7); // MOSI
  LPC_IOCON->PIO0_17 |= 0x2;

  /* SSP SSEL is a GPIO pin */
  LPC_IOCON->PIO0_27 = 0x0;     // configure as GPIO pin
  LPC_GPIO0->MASK = (1<<27);
  LPC_GPIO0->DIR |= (1<<27);    // set in output mode */
  LPC_GPIO0->CLR = 1 << 27;

  /* Set DSS data to 9-bit, Frame format SPI, CPOL = 0, CPHA = 0, and SCR is 0 */
  LPC_SSP->CR0 = 0x0008;

  /* SSPCPSR clock prescale register, master mode, minimum divisor is 0x02 */
  LPC_SSP->CPSR = 0x4;  // SPI clock will run at 6 MHz

  /* set Master mode and enable the SPI */
  LPC_SSP->CR1 = 0x2;
}