src/Hardware.h

   1 #ifndef AVR_HARDWARE_H
   2 #define AVR_HARDWARE_H
   3
   4 namespace avr {
   5
   6         class Bus;
   7         class IORegister;
   8
   9         /**
  10          * @author Tom Haber
  11          * @date Apr 26, 2008
  12          * @brief Abstraction of all internal devices
  13          *
  14          * This is an abstraction of all the internal devices inside
  15          * an AVR chip. These encompass timers, usart, spi, etc
  16          *
  17          * Hardware can negotiate its timing with the Bus,
  18          * \e step is called based on this timing.
  19          */
  20         class Hardware {
  21                 public:
  22                         Hardware(Bus & bus) : bus(bus), holdCycles(0) {}
  23                         virtual ~Hardware() {}
  24
  25                 public:
  26                         /**
  27                          * Attach a register with name \e name to the hardware.
  28                          */
  29                         virtual bool attachReg(const char *name, IORegister *reg) = 0;
  30
  31                         /**
  32                          * Finishes the construction of the hardware.
  33                          * This should verify the registers and parameters
  34                          * @returns true if build was successful.
  35                          */
  36                         virtual bool finishBuild() { return true; }
  37
  38                         /**
  39                          * An attached register changed state.
  40                          */
  41                         virtual void regChanged( IORegister *reg ) = 0;
  42
  43                         /**
  44                          * An attached register is accessed.
  45                          */
  46                         virtual void regAccess( IORegister * /*reg*/ ) {}
  47
  48                         /**
  49                          * Perform a single step.
  50                          */
  51                         virtual void step() {}
  52
  53                         /**
  54                          * Reset the internal hardware.
  55                          */
  56                         virtual void reset() {}
  57
  58                         /**
  59                          * Called just before an interrupt handler is invoked.
  60                          */
  61                         virtual void beforeInvokeInterrupt(unsigned int /*vector*/) {}
  62
  63                 public:
  64                         /**
  65                          * Are we holding the CPU?
  66                          * @warning only call this once per CPU cycle.
  67                          */
  68                         bool isHoldingCPU();
  69
  70                 protected:
  71                         /**
  72                          * Set the number of cycles to hold the CPU.
  73                          */
  74                         void setHoldCycles(unsigned int cycles);
  75
  76                 protected:
  77                         Bus & bus;
  78                         unsigned int holdCycles;
  79         };
  80
  81         inline void Hardware::setHoldCycles(unsigned int cycles) {
  82                 holdCycles = cycles;
  83         }
  84
  85         inline bool Hardware::isHoldingCPU() {
  86                 if( holdCycles != 0 )
  87                         holdCycles--;
  88
  89                 return (holdCycles != 0);
  90         }
  91
  92 }
  93
  94 #endif /*AVR_HARDWARE_H*/