| [2] | 1 | /* Author : Rick van der Zwet
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| 2 | * S-number : 0433373
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| 3 | * Version : $Id: README.txt 217 2007-09-10 19:35:36Z rick $
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| 4 | * Copyright : FreeBSD Licence
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| 5 | */
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| 6 |
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| 7 | =Assignment 1=
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| 8 | ==Static instructions==
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| 9 | We could define static instructions into groups:
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| 10 | * Loop 1 : 18
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| 11 | * Loop 2 : 30
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| 12 | -------------------------------------------------
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| 13 | TOTAL : 58
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| 14 |
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| 15 | ==Dynamic instructions==
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| 16 | Dynatic instructions into groups
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| 17 | * Initial intructions : 0
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| 18 | * Intructions loop 1 init : 2
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| 19 | * Intructions loop 1 main : (3 + 13) * 20 + 4
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| 20 | ** *20 cause 20 times loop
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| 21 | ** +4 cause of the last compare (including jump)
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| 22 | * Intructions loop 2 init : 4
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| 23 | * Intructions loop 2 main : (3 + 22) * 20 + 4
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| 24 | ** *20 cause 20 times loop
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| 25 | ** +4 cause of the last compare (including jump)
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| 26 | -------------------------------------------------
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| 27 | TOTAL : 834
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| 28 |
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| 29 | ==Data accesses==
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| 30 | * Loop 1 : 1 + 1 * 21 + 5 * 20
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| 31 | * init, compare, inner loop
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| 32 | * Loop 2 : 2 + 1 * 21 + 8 * 20
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| 33 | * init, compare, inner loop
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| 34 | -------------------------------------------------
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| 35 | TOTAL : 305
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| 36 |
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| 37 |
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| 38 | =Optimalisation=
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| 39 |
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| 40 | The most easy way to kill all dynamic instructions will be calculating
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| 41 | the final result and write the results into the memory and registery
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| 42 | directly, meaning at the end
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| 43 | for i = 1 .. 20
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| 44 | B[i] = i
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| 45 | A[i] = B[i-1] + C
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| 46 | C = 42
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| 47 | i = 20
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| 48 | $2 = 20 (last value of i, last loop compare)
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| 49 | $3 = 0 (last loop compare)
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| 50 | $4 = 42
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| 51 |
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| 52 | ==Static intructions==
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| 53 | * Number of intructions will be: 84
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| 54 |
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| 55 | ==Dynamic instructions==
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| 56 | * Dynamic intructions eq to static intructions as we define all
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| 57 | results directly: 84
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| 58 |
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| 59 | ==Data accesses==
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| 60 | * Cause we also have some references to the registery not all calls are
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| 61 | data accesses, the count stops at:
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| 62 | * B = 19
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| 63 | * A1 = 2
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| 64 | * A = 18
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| 65 | * C = 1
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| 66 | * i = 1
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| 67 | ----------
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| 68 | TOTAL = 41
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| 69 |
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| 70 | ==Speedup==
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| 71 | Dynamic count old: 834
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| 72 | Dynamic count new: 84
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| 73 | Speedup in execution time: 1 / (84/834) = 9.93
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| 74 | quote Van Thieu Vu, why we do not use the Amdahl law over here
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| 75 | Here we calculate the performance gain of an optimized program while the
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| 76 | Amdahl's law which you mentioned is used to calculate the performance gain
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| 77 | of an improved computer. In your case, the speedup is 1/(84/834).
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| 78 |
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| 79 |
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| 80 |
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| 81 |
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| 82 |
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| 83 |
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| 84 |
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