`CPU`

Class:	CPU
Name:	CPU
Comment:	Simulates P-Code CPU, normally executes in a simple loop. fetchInstruction address translation check valid instruction executeInstruction if interruptsEnabled then handleInterrupts check InterruptQ to see if any are due at this point in time any due are handled in a loop and usually result in calling a kernel method, possibly a differnet method for each interrupt OR same method but pass the Interrupt class as a parameter. oneTick increment CPU clock if time for a TimerInterrupt than add to the InterruptQ so that the interrupt is handled at the end of the next instruction execution cycle should include a simple method to change when TimerInterrupts occur
Collaborators:	Interrupt - store information about type, source etc Instruction - store opcode, parameter etc Address - possibly used for translation mechanisms PriorityQueue - used to store interrupts that are scheduled to happen

Instruction theInstruction = fetchInstruction( Address real )
int result = executeInstruction( theInstruction )
handleInterrupts - cycle through all interrupts in queue and handle those ones that are either past time or ready to be handled,
Handling can either be just generating messages for the kernel or modifying CPU H/W so another step actually does the handling. The idea for the latter method is so that you have problems if two intterrupts occur at the same time.
enableInterrupts
disableInterrupts - what happens when an interrupt is attempted when interrupts are disabled?
boolean interruptsEnabled() - TRUE if interrupts can occur
virtualToReal( Address virtual, Address real ) - perform address tranlation mechanism
readMemory( Address real )
int readRegister( int register )
writeRegister( int register, int value )
oneTick - advance CPU clock one tick, check if a timer interrupt should now be generate, if yes add one to the interrupt queue
generateInterrupt( Interrupt theInt ) - add an interrupt to the queue

CPU