Homework 3 (Version 1.0) Solutions - North Carolina State University ECE 463

NC State University Department of Electrical and Computer Engineering ECE 463/563: Fall 2018 (Rotenberg) Homework #3 (Version 1.0) Due: 5:00PM, Friday, November 23, 2018 NCSU Honor Pledge: "I have neither given nor ...

NC State University Department of Electrical and Computer Engineering ECE 463/563: Fall 2018 (Rotenberg) Homework #3 (Version 1.0) Due: 5:00PM, Friday, November 23, 2018 NCSU Honor Pledge: "I have neither given nor received unauthorized aid on this test or assignment." Student’s signature or electronic signature: _______________________ (sign by typing your name) Course number: _________________ (463 or 563 ?) Rules for all homeworks: All homeworks must be handed in electronically via WolfWare. The required format is a single PDF file. The late policy is stated in the course syllabus. Note: You must show all your work to receive full credit for a given problem. Pipeline Design 1. [20 points] The first pipeline we designed in class, without a BTB and without register file bypasses, is shown in Figure 1. Various parts of the pipeline are labeled in the figure with numbers. Circular labels are used for wires, buses, etc., and start at number 1. Triangular labels are used for components (adders, muxes, SRAMs, logic blocks, etc.) and start at number 80. L1 Instr. Cache and L1 Instr. TLB + 4 NPC PC IR Reg. File (RF) read_port_1 read_port_2 write_port rs1 rs2 rd imm A B IMM upper: sign extend lower: assemble decode control signals ALU MUX MUX L1 Data Cache and L1 Data TLB A op B ? branch MUX NPC LMD B ALUoutput ALUoutput control signals control signals Instruction Fetch (IF) Instruction Decode (ID) Execute (EX) Memory (MEM) Writeback (WB) is_branch_inst squash squash squash branch MUX 0 1 rd rd rd opcode func3 func7 80 9 11 12 1 2 3 4 5 6 7 8 10 13 14 15 16 17 18 19 20 21 22 23 25 24 26 27 28 29 30 31 32 33 81 82 83 84 85 86 87 88 89 90 91 Figure 1. Pipeline diagram for the first pipeline we designed in class, without a BTB and without register file bypasses. 1. (continued) Fill in the table. Next to each item, provide the letter (e.g., A, B, etc.) of the description that best describes the item. Choose from the descriptions below. ITEM letter of the description that best describes the item (choose exactly one letter from the list of descriptions below) (if applicable, a letter may be used more th