//Pull from memory to a register
public void Pull(Register8 register)
{
systemMemory.StackRead(register, internalRegister);
if (register.Get() == 0)
{
statusRegister.SetZero();
}
Decrement();
}
//Read from memory into an 8 bit register
public bool Read(Register8 register, ushort location)
{
if (location > 0xffff)
{
//Sets the overflow flag on the status register
statusRegister.SetOverflow();
return(false);
}
register.Set(memory[location]);
return(true);
}
//Push the contents of a register to the stack
public void Push(Register8 register)
{
//The current push function always ignores location 0xff
//Effectively reducing the stack space available by one byte
//TODO: Fix this, making location 0xff usable
Increment();
systemMemory.StackWrite(register, internalRegister);
//Sets the zero flag on the status register
if (register.Get() == 0)
{
statusRegister.SetZero();
}
}
//Write the contents of an 8-bit register to memory
public bool Write(Register8 register, ushort location)
{
//If the operation is a write to the stack, the write fails.
if (IsWriteToStack(location))
{
return(false);
}
if (location > 0xffff)
{
//Sets the overflow flag on the status register
statusRegister.SetOverflow();
return(false);
}
memory[location] = register.Get();
return(true);
}
//Function for the Stack Pointer to write to memory
public bool StackWrite(Register8 register, ushort location)
{
memory[location] = register.Get();
return(true);
}
//Function for the Stack Pointer to read from memory
//Probably not needed as reads from stack are fine
//with normal Read, but here for symmetry
public bool StackRead(Register8 register, ushort location)
{
register.Set(memory[location]);
return(true);
}