减小beq损失：单周期分支，ID段完成 Flushed Continued add Sr1.5r2,5r3 sw$1,0r2) sUb51,5r2,33 wsr1.05r2) slt $r1,5r2.$r3 Flushed Continued IF ID EX MEM WB add Sr1.$r2.Sr3 Beg Sr2.Sr5.0x08 sw Sr1,0(Sr2) sub Sr1.,Sr2.Sr3 sit Sr1.Sr2,Sr3 ←---Flushed---- Add Sr1,$r2,Sr4 Add Sr2 Sr2,Sr3 Beq Sr2.Sr5 Lw Sr2.0x04(Sr0)Lw Sr4.Ox0d(Sro) IF EX MEM WB IF ID EX MEM WB Instruction flow Instruction flow Program execution 200 400 600 800 1000 1200 1400 Time order (in instructions) 图4-29，设D段完成， add x4,x5,x6 Instruction fetch Reg ALU Data access Reg 则只需Stall-一个cc! beq x1,x0,40 Instruction Data 200ps fetch Reg ALU access Reg bubble bubble bubble bubble bubble 0 or x7,x8,x9 Instruction 400ps fetch Reg ALU Data access Reg减小beq损失：单周期分支，ID段完成 图4-29，设ID段完成， 则只需Stall一个cc！