In the class, we have shown how to maximize performance on our pipelined datapath with forwarding and stalls on a use following a load. Rewrite the following code to minimize performance on this datapath – that is, reorder the instructions so that this sequence takes the most clock cycles to execute while still obtaining the same result:
lw $3, 0($5)
lw $4, 4($5)
add $7, $7, $3
add $8, $8, $4
add $10, $7, $8
sw $6, 0($5)
beq $10, $11, loop
The only stalls occur when loads are followed by uses. There are two occurrences of this in this code fragment. So, reorder as follows:
lw $3,0($5)
add $7, $7, $3
lw $4, 4($5)
add $8, $8, $4
add $10, $7, $8
sw $6, 0($5)
beq $10, $11, Loop
In the class, we have shown how to maximize performance on our pipelined datapath with forwarding...
The pipelined MIPS datapath executes the following code: lw $16, 12($4) lw $17, 16($4) beq $8, $9, skip sw $18, 16($4) add $18, $16, $18 How many cycles does it take to execute the code if the branch is not taken?
Computer architecture help: (60 points) The following instructions are executed on the 5-stage MIPS pipelined datapath. add r5,r2, r1 lw r3, 4(r5) lw r2, 0(r2) or r3, r5, r3 sw r3, 0(r5) (a) (20 points) List the data hazards in the above code. For each data hazard identified, clearly mark the source and the destination. For example you can say, there is a data hazard from instruction X to instruction Y on register Z. (b) (20 points) Assume there is...
The code chain below is executed on a data forwarding, 5-stage pipelined processor. Which of the following instructions will encounter a stall? Write the instruction number along with the number of stall cycles that instruction experiences. (Note the data forwarding) 1. add $4, $5, $6 2. add $7, $4, $5 3. sw $8, 0($7) 4. add $8, $8, $6 5. lw $6, 0($8) 6. add $10, $9, $8
Consider the following code to be executed on a pipelined processor lw $s1, 40(Ss6) add $s6, $s2, $s2 sw Ss6, 48(Ss1) a. Include stalls/nops in the code so it executes correctly in the cases of (i) No forwarding (ii) ALU-ALU for warding, (iii) Full forwarding b. In each case calculate the number of clock cycles required to execute the code c. Assume further that the clock cycle time is 110 ps with no forwarding, 120 ps with ALU-ALU forwarding and...
Given the following sequence of instructions to be executed on a 5-stage pipelined datapath as decrypted in our textbook: I1: add $8, $12,$10 12: SW $9,0 ($8) 13: lw $8,4($9) I4: and $12,$12,$8 15: SW $8,0($9) a. List true dependencies in the given sequence in the format of (register involved producer instruction, consumer instruction). Use labels to indicate instructions For example: ($0, I10, I11) means a true dependence between instruction I10 and I11: value of register $0 is generated by...
2 This exercise is intended to help you understand the relationship between forwarding hazard detection, and ISA design. Problems in this exercise refer to the following sequence of instructions, and assume that it is executed on a 5-stage pipelined datapath: lw r5,4(r5) add r5,r2,r5 Iw r3,0(r5) or r3,r5,r3 sw r4,0(r5) 2.1 If there is no forwarding or hazard detection, how many nops needed to be inserted to ensure correct execution, and how many cycles needed to execute the codes? 2.2...
1. Assume that individual stages of the datapath have the following latencies: IF ID EX MEM WB 250 ps 350 ps 150 ps 300 ps 200 ps Also, assume that instructions executed by the processor are broken down as follows: alu beq lw sw 45% 20% 20% 15% What is the total latency of an ?w instruction in a pipelined and non-pipelined processor? Instead of a single-cycle organization, we can use a multi-cycle organization where each instruction takes multiple cycles...
Reschedule (i.e., re-order) the instructions within the loop to improve performance. The loop must still produce the same results. Show timing of this MIPS instruction sequence through the pipeline, for two iterations of the loop. Show all stalls clearly, and mark with arrows all cases where forwarding takes place, as in our lectures. loop: lw $t0, 0($s0) lw $t1, 4($s0) add $t0, $t1, $t0 sw $t0, 0($s1) addi $s0, $s0, 8 addi $s1, $s1, 4 bne $s0, $s5, loop
2 This exercise is intended to help you understand the relationship between forwarding hazard detection, and ISA design. Problems in this exercise refer to the following sequence of instructions, and assume that it is executed on a 5-stage pipelined datapath: w r5,4(r5) add r5,r2,r5 w r3,0(r5) or r3,r5,r3 sw r4,0(r5) 2.1 If there is no forwarding or hazard detection, how many nops needed to be inserted to ensure correct execution, and how many cycles needed to execute the codes? 2.2...
1. Given the following instruction sequence for the MIPS processor with the standard 5 stage pipeline $10, S0. 4 addi lw S2.0(S10) add sw S2,4(510) $2, $2, $2 Show the data dependences between the instructions above by drawing arrows between dependent instructions (only show true/data dependencies). a. Assuming forwarding support, in what cycle would the store instruction write back to memory? Show the cycle by cycle execution of the instructions as they execute in the pipeline. Also, show any stalls...