Class IO_Register

Class Documentation

class IO_Register

Simulation model for a 8-bits I/O register that is a vehicle for data transfer between the CPU and I/O peripherals.

Peripherals can be added as handlers to a register to be notified of accesses (read or write) by the CPU.

Each bit of the register can be marked as used/unused or read-only. this is taken into account on write access for error checks.

Public Functions

explicit IO_Register(bool core_reg = false)

Build a register.

Parameters:

core_reg – set to true if the register is handled by the core. The effect is to bypass read-only/use masks checks

IO_Register(const IO_Register &other)
~IO_Register()
inline uint8_t value() const

Simple inline interface to access the value.

inline void set(uint8_t value)

Simple inline interface to access the value.

void set_handler(IO_RegHandler &handler, uint8_t use_mask, uint8_t ro_mask)

Add a handler to this register.

Note

the bitmasks are OR’d with any pre-defined mask.

Parameters:

  • handler – handler to add

  • use_mask – bitmask indicating the used bits (‘1’s)

  • ro_mask – bitmask indicating the read-only bits (‘1’s)

uint8_t cpu_read(reg_addr_t addr)

CPU read access to the register. The handlers’ read callbacks are called then the register value is returned.

bool cpu_write(reg_addr_t addr, uint8_t value)

CPU write access to the register. The handlers’ write callbacks are called.

Note

that if the register has no handler, all 8 bits are read-only except if core_reg was true at construction

Returns:

true if the read-only rule has been violated, i.e. attempting to write a read-only or unused bit with ‘1’.(temporary removed)

uint8_t ioctl_read(reg_addr_t addr)

I/O peripheral interface for read/write operation on this register

void ioctl_write(reg_addr_t addr, uint8_t value)

I/O peripheral interface for read/write operation on this register

IO_Register &operator=(const IO_Register&) = delete