and x12,x2,x5 beq x1,x3,16 sub x10,x4,x8 before<1> before<2> Hazard detection unit Flush Taken EX/MEM MEMNWB 36 sub x10,X4,×8 40 beq ×1, ×3,16 44 and x12,x2,x5 memory Data M口X 48 or x13,x2,x6 memory 52 add x14, ×4,×2 56 sub x15, x6,x7 721d ×4,50(x7) Clock 3 判定taken,则： 更新PC,Clear IF/ID d对，50x7) Bubble(nop) beq x1,x3.16 5ubx10,.,+ before<1> 取“ld”,bubble down Hazard REG L REC EX/MEM sub MEMWB beq MEM REG and memory Data M Iw ·图4-60 从cc4开始变为nop Clock 4Flush & Taken • 图4-60 判定taken，则：更新PC，Clear IF/ID 从cc4开始变为nop 取“ld”，bubble down