13 06 2023 E S Silvano

Pagina 1

Surname (COGNOME) SOLUTION Name POLIMI Personal Code Signature Politecnico di Milano, 13 June, 2023 Course on Advanced Computer Architectures Prof. C. Silvano EX1 ( 5 points) EX2 ( 5 points) EX3 ( 5 points) Q1 ( 5 points) Q2 ( 5 points) QUIZZES ( 8 points) TOTAL (33 points) Course on Advanced Computer Architectures – prof. C. Silvano EXAM 13 June 2023 – Please write in CAPITAL LETTERS AND BLACK/BLUE COLORS!!! Page 1 - SOLUTION EXERCISE 1 – TOMASULO (5 points) Let’s consider the following assembly code. to be executed on a CPU with dynamic scheduling based on TOMASULO algorithm with all cache HITS, a single Common Data Bus and: • 2 RESERVATION STATIONS (RS1, RS2) with 1 LOAD/STORE unit (LDU1) with latency 4 • 2 RESERVATION STATION (RS3, RS4) with 1 ALU/BR unit (ALU1) with latency 2 Please complete the following table: INSTRUCTION ISSUE START EXEC WRITE RESULT Hazards Type RSi UNIT I1: lw $f0,0($r1) 1 2 6 RS1 LDU1 I2: lw $f2,4($r1) 2 RS2 LDU1 I3: lw $f4,8($r1) I4: lw $f6,C($r1) I5:fadd $f8,$f0,$f2 I6:fadd $f10,$f4,$f6 I7:fadd $f10,$f8,$f10 I8: sw $f10,4($r1) Calculate the CPI: CPI = _______________________________________________________________ Course on Advanced Computer Architectures – prof. C. Silvano EXAM 13 June 2023 – Please write in CAPITAL LETTERS AND BLACK/BLUE COLORS!!! Page 2 - SOLUTION Feedback: INSTRUCTION ISSUE START EXEC WRITE RESULT Hazards Type (*) RSi UNIT I1: lw $f0,0($r1) 1 2 6 RS1 LDU1 I2: lw $f2,4($r1) 2 7 11 STR. LDU1 RS2 LDU1 I3: lw $f4,8($r1) 7 12 16 STR. RS1 + STR. LDU1 RS1 LDU1 I4: lw $f6,C($r1) 12 17 21 STR. RS2 + STR.LDU1 RS2 LDU1 I5:fadd $f8,$f0,$f2 13 14 17 STR. CDB/RF WRITE RS3 ALU1 I6:fadd $f10,$f4,$f6 14 22 24 RAW $f6 RS4 ALU1 I7:fadd $f10,$f8,$f10 18 25 27 STRUCT RS3 + RAW Sf10 RS3 ALU1 I8: sw $f10,4($r1) 19 28 32 RAW $f10 RS1 LDU1 CPI…