The LEG 8 Datapath

Notes

• 
• The effect of each of the seven control signals, page 276

• Signal	Effect when deasserted	Effect when asserted
  Reg2Loc	Register comes from Rm field 20:16	Register comes from Rt field 4:0
  RegWrite	None	The register on the Write register input is written with the value of the Write data input
  ALUSrc	The second ALU operand comes from the second register file output (Read data 2)	The second ALU operand is sign-extended, lower 16 bits of the instruction
  PCSrc	The PC is replaced by the output of the adder that computes the value of PC+4	The PC is replaced by the output of the adder that computes the branch target
  MemRead	NONE	Data memory contents designated by the address input are put on the Read data output
  MemWrite	NONE	Data memory contents designed by the address input are replaced with the value on the Write data input
  MemToReg	The value fed into the register Write data input comes from the ALU	The value fed into the register Write data input comes from the data memory

• ALU : add, compare, subtract, AND, OR