1.1.1 structure and function of processor Flashcards
architecture, fde, performance of cpu, pipelining, von neumann vs harvard
what is the role of the cpu?
processes data by executing program instructions
what is the role of the alu?
performing arithemetic calculations and logical operations
what are the specific operations that the alu is responsible for?
addition, subtraction, multiplication, division
logical operations
comparison between values
shifting binary patterns to left or right
what is the role of the cu?
controls and manages the execution of instructions, the sequence of operations, directs the flow of data with control signals, decodes every instruction that the cpu will execute
what is the role of the clock?
generating regular clock pulses by emitting a signal that is used to synchronise the operations of the processor components
how do clock pulses work?
the clock generates regular clock pulses by emitting a signal that continuously oscillates between a low (0) and a high (1) state
what is a clock period?
the time taken between 2 sequential rising edges of a signal state (it corresponds to one clock cycle)
what is a rising edge?
a change from a low (0) state to a high (1) state of clock signals
what is a falling state?
a change from a high (1) state to a low (0) state of clock signals
what is clock rate / clock freq / clock speed?
number of clock cycles that can be completed in 1 second (measured in Hz) it is the inverse of the clock period
what is a register?
locations of computer memory within the processor that provide extremely fast access
what is a general-purpose register?
a register to temporarily store and access the results of operations
what is a special-purpose register?
processor-based registers that are used for a specific purpose
what is the role of the pc?
holds the address of the next instruction to be executed by the processor
what is the role of the cir?
holds the current instruction that the cpu is executing
what is the role of the status register (sr)?
used to store information about the result of the last instruction that the alu executed
how does the sr work?
each bit within the status register acts as a flag to indicate if an error or exception has occurred within the process or to enable or disable interrupts to be raised
what is an interrupt?
an event outside the program process that requires the attention of the cpu
what is the role of the mar?
temporarily hold the address of the memory location that the cpu needs to access, either to read from or to write to
what is the role of the mdr / mbr?
temporarily holds the data that are read from or written to main memory
what is the role of the acc?
stores the result of any calculation processed by the alu
what is the difference between general-purpose registers and the acc?
the acc holds any RESULT, the general purpose holds them temporarily while calculations are in the process of being completed
what has to happen before the fde cycle can take place?
the program instructions need to be in machine code and the program instructions have been loaded into RAM
what happens at the end of the fde?
the cpu checks the status register to see if an error, exception or interrupt needs to be handled
what is an exception?
an unexpected behaviour that occurs during execution