第一阶段：取指 根据PC从MEM中取指，IR=MEM[PC] 计算NPC,PC=PC+4 控制信号：lorD,MemRead,IRWrite;ALUSrcA,ALUSrcB ALUOp,PCWrite orD MemRead MemWrite IRWrite RegWrite ALUSrcA PC 0 Instruction Read Address [19-15 register 1 Read Instruction Read data 1 Memory [24-20] 1 Zero register 2 MemData Instruction Registers ALU ALU ALUOut [11-7刀 Write result Read Write register data 2 M data Instruction register Write data 2 Instruction [31-0 PC“后写”？ Memory Imm data Gen ALU register control Instruction [6-0] MemtoReg ALUSrcB ALUOp11 第一阶段：取指 • 根据PC从MEM中取指，IR=MEM[PC] • 计算NPC，PC=PC+4 • 控制信号：IorD, MemRead, IRWrite；ALUSrcA, ALUSrcB, ALUOp, PCWrite PC“后写”？