| [2] | 1 | /* Author : Rick van der Zwet
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| 2 | * S-number : 0433373
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| 3 | * Version : $Id: memory.h 363 2007-12-03 06:07:31Z rick $
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| 4 | * Copyright : FreeBSD Licence
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| 5 | * Description : page-mode DRAM with a page-size of PAGESIZE words, a
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| 6 | * random access time of RAS clock cycles and a 'next
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| 7 | * access time' of NAT clock cycles.
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| 8 | */
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| 9 |
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| 10 | #include <stdio.h>
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| 11 | #include <stdlib.h>
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| 12 | #include <string.h>
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| 13 | #include "common.h"
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| 14 |
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| 15 | void
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| 16 | memory_dram(const int PAGESIZE, const int NAT, const int RAS)
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| 17 | {
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| 18 | struct bus2_t line;
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| 19 | struct result_t output = {0, 0, 0, 0};
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| 20 |
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| 21 | /* Keep track of which page memory is, cause switching means a lot of
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| 22 | * extra work/cycles in terms of empty memory, moving to new bank
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| 23 | */
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| 24 | int current_page = 0;
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| 25 |
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| 26 | /* Page location needed by new request */
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| 27 | int page_needed = 0;
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| 28 |
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| 29 | /* Part of page needed by new request */
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| 30 | int part_needed = 0;
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| 31 |
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| 32 | /* Every page has got 64 entries which all can be busy,
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| 33 | * by convention 0 means not busy else busy
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| 34 | */
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| 35 | int * partbusy = (int *)malloc(sizeof(int) * PAGESIZE);
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| 36 |
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| 37 | int i; /* Temp counter */
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| 38 |
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| 39 | /* Init all parts to be available in the beginning */
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| 40 | memset(partbusy, FALSE, sizeof(int) * PAGESIZE);
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| 41 |
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| 42 | while (fscanfbus2(&line) != EOF) {
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| 43 | /* Process the counts */
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| 44 | setstats(&line, &output);
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| 45 |
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| 46 | /* New request means new cycle as well */
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| 47 | output.cycles++;
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| 48 |
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| 49 | /* Find proper page, do not take advantage of C div operator on
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| 50 | * int which is rounding directly, but use more safe/portable
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| 51 | * approch */
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| 52 | part_needed = line.address % PAGESIZE;
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| 53 | page_needed = (line.address - part_needed) / PAGESIZE;
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| 54 |
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| 55 | /* Determine wether we did hit the right page or not */
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| 56 | if (page_needed == current_page) {
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| 57 | /* Check whether part is busy, which will result in waiting
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| 58 | * till part access is granted
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| 59 | */
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| 60 | if (partbusy[part_needed] != FALSE) {
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| 61 | /* Worst case senario on refresh */
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| 62 | output.cycles += RAS;
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| 63 | memset(partbusy, FALSE, sizeof(int) * PAGESIZE);
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| 64 | }
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| 65 | } else {
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| 66 | /* Wait till all pending calls in current page are completed
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| 67 | * 'Abuse' t to be identifier wether some bank was lowered
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| 68 | */
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| 69 | /* Worst case senario on refresh */
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| 70 | output.cycles += RAS;
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| 71 | memset(partbusy, FALSE, sizeof(int) * PAGESIZE);
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| 72 |
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| 73 | /* Switch to new page */
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| 74 | current_page = page_needed;
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| 75 | output.cycles += NAT;
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| 76 | output.conflicts++;
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| 77 | }
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| 78 |
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| 79 | /* Set new memory access */
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| 80 | partbusy[part_needed] = RAS + TRANSFER;
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| 81 |
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| 82 | /* Process all parts to lower cycle count by one */
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| 83 | for (i = 0; i < PAGESIZE; i++) {
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| 84 | if (partbusy[i] != FALSE)
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| 85 | partbusy[i]--;
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| 86 | }
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| 87 | }
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| 88 |
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| 89 | /* Make sure remaining data leaves memory safely */
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| 90 |
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| 91 | /* Worst case senario on refresh */
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| 92 | output.cycles += RAS;
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| 93 |
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| 94 | /* Delete allocated memory */
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| 95 | free(partbusy);
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| 96 |
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| 97 | printfresult(stdout, &output);
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| 98 | }
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