source: liacs/ca/opdr3/memory_bank.c@ 144

/* Author      : Rick van der Zwet
 * S-number    : 0433373
 * Version     : $Id: memory.h 363 2007-12-03 06:07:31Z rick $
 * Copyright   : FreeBSD Licence
 * Description : BANKS-bank word-interleaved memory with random access time
 *               of RAS clock cycles
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "common.h"

void
memory_bank(const int BANKS, const int RAS)
{
    struct bus2_t line;
    struct result_t output = {0, 0, 0, 0};

    int bankneeded;
    int i,j; /* Temp counter */
    int t; /* Temp variable to hold condition */

    /* BANKS bank memory, so BANKS places which could be busy 
     * by convention 0 means not busy else busy
     */
    int * bankbusy = (int *)malloc(sizeof(int) * BANKS);

    /* Init all banks to be available in the beginning */
    for (i = 0; i < BANKS; i++)
        bankbusy[i] = FALSE;

    while (fscanfbus2(&line) != EOF) {
        /* Process the counts */
        setstats(&line, &output);

        /* New request means new cycle as well */
        output.cycles++;

        /* Find proper bank */
        bankneeded = line.address % BANKS;

        /* Determine whether the bank is busy, if so this will result
         * in waiting for completion of this bank . It is not allowed
         * for next calls to memory to complete before this one
         */
        if (bankbusy[bankneeded] != FALSE) {
            output.conflicts++;

            /* Lower memory count till memory bank  is free */
            t = bankbusy[bankneeded];
            for (i = 0; i < t; i++) {
                for (j = 0; j < BANKS; j++) {
                    if (bankbusy[j] != FALSE)
                        bankbusy[j]--;
                }
                output.cycles++;
            }
        }

        /* Set bank to be busy */
        bankbusy[bankneeded] = RAS + TRANSFER;

        /* Process all banks to lower cycle count by one */
        for (i = 0; i < BANKS; i++) {
            if (bankbusy[i] != FALSE)
                bankbusy[i]--;
        }
    }

    /* Make sure remaining data leaves memory safely */
    /* 'Abuse' t to be identifier wether some bank was lowered */
    for (i = 0; i < RAS; i++) {
        t = FALSE;
        for (j = 0; j < BANKS; j++) {
            if (bankbusy[j] != FALSE) {
                bankbusy[j]--;
                t = TRUE;
            }
        }
        /* Check if something was changed */
        if (t == FALSE)
            break;

        output.cycles++;
    }


    /* delete allocated memory */
    free(bankbusy);

    printfresult(stdout, &output);
}