CPU architecture

CPU architecture

1. Embedded systems

   • Computers built into other devices
     • Dedicated systems
   • Often monitor and control
     • Very efficient focusing on one thing
   • in a car they could display tire pressure on the computer

2. CPU

   • Brain of the computer
     • Processes all data & instructions
     • Power & efficiency
       • Depends on number of cores, cache size and clock speed
   • Architecture
     • Von Neumann
     • Harvard
   • Control Unit
     • Controls the CPU and manages FETCH DECODE EXECUTE
     • Controls flow of date in CPU and out
     • Cache (part of CPU)
       • Fast memory for frequently used data
       • Low capacity because its expensive
       • Levels
         • L1 is fastest but less space
           • L2 is slower but more space etc
   • Arithmetic Logic Unit
     • Does caalculations + - compare * /
       • And OR Not and binary shift
     • Contains Accumulator Register

3. Registers

   • The Program Counter holds the memory address of the instruction for each cycle
     • (PC)
     • On CPU not a register
   • The accumulator stores intermediate results of calculation in the ALU
     • (ALU)
     • On CPU not a register
   • The Memory Address Register holds any memory address about to be used by the CPU
     • (MAR) REGISTER
     • The address might point to data or a CPU instruction
   • The Memory Data Register holds the actual data or instruction.
     • This may have been fetched from memory or be waitng to be written to memory
     • (MDR) REGISTER

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