Register File

• A set of registers that can be read and written by supplying a register number to be accessed
• Implementation
  • Array of registers built from D flip-flops
  • Writing
    • Decoder takes in the input and feeds one output to an into each register’s clock (register can only be changed when its clock input changes)
    • Register data is connected to every register
  • Reading
    • Multiplexers select the register signal to output
• Think of accessing an array when accessing registers
• ARM registers
  • 32 registers
  • 2 read ports and 1 write port
    • because most instructions have two inputs and one output
    • makes it so both can be read in one clock cycle