最新lab3复杂流水线实验报告.docx

1、最新lab3复杂流水线实验报告lab3复杂流水线实验报告Lab3复杂流水化实验Experiment1: To study the basics of forwarding. For all the programs please select Stall Detection and Forwarding should be ON.(a)Write a sample program that forwards between EXE stage and MEM stage on upper input of the ALU.Write the program below and show for

2、warding with arrow. Test it on the simulator and mention what value is being forwarded. DO NOT USE LW INSTRUCTION.Instruction123456789ADD R1,R2,R3IFIDEXEMEMWBSUB R5,R1,R4IFIDEXEMEMWB 其中ADD指令中在MEM阶段的ALUout-555（R2+R3）前递到SUB指令的EXE阶段的upper input。(b)Write a sample program that forwards between EXE stage

3、and WB stage on upper input of the ALU.Write the program below and show forwarding with arrow. Test it on the simulator and mention what value is being forwarded. DO NOT USE LW INSTRUCTION.Instruction123456789ADD R1,R2,R3IFIDEXEMEMWBNOPIFIDEXEMEMWBSUB R5,R1,R4IFIDEXEMEMWB其中ADD指令中在WB阶段的输出555（R2+R3）前递

4、到SUB指令的EXE阶段的upper input。(c)Write a sample program that forwards between EXE stage and MEM stage on lower input of the ALU.Write the program below and show forwarding with arrow. Test it on the simulator and mention what value is being forwarded. DO NOT USE LW INSTRUCTION.Instruction123456789ADD R1,

5、R2,R3IFIDEXEMEMWBSUB R5,R4,R1IFIDEXEMEMWB 其中ADD指令中在MEM阶段的ALUout-555（R2+R3）前递到SUB指令的EXE阶段的upper input。(d) Write a sample program that forwards between EXE stage and WB stage on lower input of the ALU.Write the program below and show forwarding with arrow. Test it on the simulator and mention what val

6、ue is being forwarded. DO NOT USE LW INSTRUCTION.Instruction123456789ADD R1,R2,R3IFIDEXEMEMWBNOPIFIDEXEMEMWBSUB R5,R4,R1IFIDEXEMEMWB其中ADD指令中在WB阶段的输出555（R2+R3）前递到SUB指令的EXE阶段的upper input。(e) Write a sample program that forwards between MEM stage and WB stage. Write the program below and show forwardin

7、g with arrow. Test it on the simulator and mention what value is being forwarded.Instruction123456789LW R1,0(R2)IFIDEXEMEMWBSW R3,0(R1)IFIDEXEMEMWB 其中ADD指令在WB阶段的输出555（R2+R3）前递到SW指令的MEM阶段。(f) Write a program that causes Load Use Delay Stall. See what data is to be moved and notice exactly when the re

8、quired Data is passed on to the waiting instruction. Show it as an arrow on the following diagram.Instruction123456789LW R1,0(R3)IFIDEXEMEMWBADD R2,R1 ,R3IFIDEXEEXEMEMWBBRANCH HAZARDS. (Lab Experiment 2)(a) Let us now study some branch hazard. First of all make sure that the Aggressive branching opt

9、ion is OFF, Stall Detection is ON and Forwarding is ON. Select Always Flush option from the branch Policy and write the following program. Does this program work properly. If not modify the program so that it works properly. It fills 10 memory locations memory with a value 222. Check what should be

10、the values of all the registers if this program work is to properly (no useful instruction turning into NOP or getting flushed). Carefully note the use of SLTI instruction in the following loop.ADDI R3, R0, 0ADDI R1, R0, 0ADDI R2, R0, 222Loop: Addi R1, R1, 4SW R2, 100(R1)ADDI R3, R3, 1SLTI R5, R3, 1

11、0BNEQ R5, R0, loopADDI R7, R1, 10ADDI R8, R2, 5ADDI R2, R2, 100(i)Calculate the CPI for this program. 61/65 (ii)What changes can we make to this program so that it works properly (useful instructionsafter the program do not flush) 可以在BNEQ跳转后面加3条ADD R0，R0，R0(iii)Run the same program with Predict NT o

12、ption in Branch Policy. What difference do you seewhen loop completes. Predict NT：循环执行完了顺序执行了剩下3条语句。Always Flush：循环执行完了依然将剩下3条语句flush掉了。(b) This problem is similar to problem A-1 at the end of the book. (Exercise A-1.)Note that you need to calculate the offset in the actual program in terms of numbe

13、r of instructions.Offset = -6 (A) Processor Configuration. Stall Detection ON., Forwarding: OFF, Aggressive Branching: YES, Branch Policy: Always Flush. Run the above program and fill the following table for the instructions in the loop body for first 2 or 3 iterations. Total Clock cycles to run the

14、 program _12345678910111213LW R1, 0(R2)IFIDEXEMEMWBADDI R1,R1, #1IFIDIDIDEXEMEMWBSW R1, 0(R2)IFIFIFIDIDIDEXEMEMWBADDI R2,R2, #4IFIFIFIDEXEMEMWBSUB R4,R3,R2IFIDIDIDEXEBNEZ R4, Loop1IFIFIFIDADDI R2, R0, 0IFADDI R3, R0, 014151617181920212223242526LW R1, 0(R2)IFIDEXEMEMWBADDI R1,R1, #1IFIDIDIDEXEMEMWBSW

15、 R1, 0(R2)IFIFIFIDIDIDEXEMEMWBADDI R2,R2, #4IFIFIFIDEXEMEMSUB R4,R3,R2MEMWBIFIDIDBNEZ R4, Loop1IDIDEXEMEMWBIFIFADDI R2, R0, 0FLUSHEDIFIDEXEMEMWBADDI R3, R0, 0(b) Redo the part (a) with forwarding ON and other processor configuration is same. Total clock cycles _12345678910111213LW R1, 0(R2)IFIDEXEME

16、MWBIFIDEXEMEMADDI R1,R1, #1IFIDEXEEXEMEMWBIFIDEXESW R1, 0(R2)IFIDIDEXEMEMWBIFIDADDI R2,R2, #4IFIFIDEXEMEMWBIFSUB R4,R3,R2IFIDEXEMEMWBBNEZ R4, Loop1IFIDIDEXEMEMWBADDI R2, R0, 0IFIFIDEXEMEMWBADDI R3, R0, 014151617181920212223242526LW R1, 0(R2)WBIFIDEXEMEMWBADDI R1,R1, #1EXEMEMWBIFIDEXEEXEMEMWBSW R1, 0

17、(R2)IDEXEMEMWBIFIDIDEXEMEMWBADDI R2,R2, #4IFIDEXEMEMWBIFIFIDEXEMEMSUB R4,R3,R2IFIDEXEEXEWBIFIDEXEBNEZ R4, Loop1IFIDIDEXEMEMWBIFIDADDI R2, R0, 0IFIFIDEXEMEMWBIFADDI R3, R0, 0实验心得：通过本次实验，我更加深刻的理解了流水线中的前递技术的实现，以及不同类型的指令在不同的阶段前递，方式也不同。同时，我对branch指令数据冒险的解决也有了一个更加清晰的认识，branch类型主要通过循环内改写和循环展开这两种方式，通过不同的实例，清楚地知道不同情况下考虑策略的不同。通过实验，更加清晰的理解了课上的理论内容，也对复杂流水化有了一个更加全面系统的认知，收获很大。