How to take care of malloc.c:2372 error

[shogunsak]

  if(cache[block].block == NULL){


  cache[block].block = (int*)malloc(blockSize * sizeof(int));


  }

This is the line that is having the error, but I am having a tough time figuring out how to allocate the memory correctly. I am trying to create a dynamic sized cache, based on user input and was told to put global variables in it even though I would have preferred not to. The majority of the code is below. It is a lot I know, I just don't know what I should be looking for.

#include<stdio.h>
#include<stdlib.h>


struct node
{
   int tag;
   int *block; //dynamic array
} *cache = NULL;


typedef struct node n;
int *mm = NULL;
int numLines, blockSize, cacheSize;


static void option1()
{
   int mmSize, i, tag;


   printf("Enter main memory size (words): ");
   scanf("%d", &mmSize);
   printf("Enter cache size (words): ");
   scanf("%d", &cacheSize);
   printf("Enter block size (words/blocks): ");
   scanf("%d", &blockSize);


   /*allocate space for MM and initialize*/


   mm = (int *)malloc(mmSize * sizeof(int));


   for (i = 0; i < mmSize; i++)
   {
       mm[i] = mmSize - 1;
   }


   numLines = cacheSize / blockSize;
   /*allocate space for cache and initialize*/
   cache = (n *)malloc(numLines * sizeof(n));


   for (i = 0; i < cacheSize; i++)
   {
       cache[i].tag = -1;
       cache[i].block = NULL;
   }
   tag = ((cacheSize/blockSize) - 1);
   return;
}


static void option2()
{
   int readOrWrite, mmAddress, writeValue, word, base, set, tag, block;


   printf("Enter 0 for read or 1 for write: ");
   scanf("%d", &readOrWrite);


   if (readOrWrite == 1)
   {


       printf("\nEnter main memory address to write to: ");
       scanf("%d", &mmAddress);
       printf("\nEnter value to write: ");
       scanf("%d", &writeValue);
   }


   else if (readOrWrite == 0)
   {
       printf("\nEnter main memory address to read from: ");
       scanf("%d", &mmAddress);
   }
   /*calculate tag, line of cache, and word associated w/ MM address*/
   printf("test1 \n");
   tag = mmAddress / cacheSize;
   block = 1;
   set = (mmAddress % cacheSize) / blockSize;
   word = mmAddress % blockSize;
   base = (mmAddress / blockSize) * blockSize;


   /*3 cases for hit/miss*/
   //CASE 1: MISS DUE TO UNALLOCATED BLOCK
   printf("test2 \n");
   if (cache[block].block == NULL)
   {
       cache[block].block = malloc(blockSize * sizeof(cache[block].block[0]));
   }
   //CASE 2: MISS DUE TO NON MATCHING TAGS
   if (cache[block].tag != tag)
   {
       cache[block].tag = tag;


       int i;


       for (i = 0; i < blockSize; i++)
       {
           cache[block].block[i] = mm[base + 1];
       }


       if (readOrWrite == 0)
       {
           printf("READ MISS!");
       }


       else if (readOrWrite == 1)
       {
           printf("WRITE MISS!");
           mm[mmAddress] = writeValue;
       }
   }
   //CASE 3: HIT IN THE CACHE, TAGS MATCH
   else if (cache[block].tag == tag)
   {
       if (readOrWrite == 0)
       {
           printf("YOU HAVE A READ HIT!");
           writeValue = cache[block].block[word];
       }


       else if (readOrWrite == 1)
       {
           printf("YOU HAVE A WRITE HIT!");
           cache[block].block[word] = writeValue;
           mm[mmAddress] = writeValue;
       }
   }
}


static void option4()
{
   int i;


   for (i = 0; i < numLines; i++)
   {
       if (cache[i].block != NULL)
       {
           free(cache[i].block);
       }


       if (cache != NULL)
       {
           free(cache);
       }
   }
}


int main()
{
   int option = 0;


   while (option != 4)
   {


       printf("\nCache memory allocation and mapping: \n");
       printf("------------------------------------\n");
       printf("1) Enter parameters \n");
       printf("2) Access cache \n");
       printf("3) Quit \n\n");
       scanf("%d", &option);


       switch (option)
       {


       case 1:
           option1();
           break;


       case 2:
           option2();
           break;


case3:
           option3();
           break;


       default:
           printf("\nOption not available, please try again. \n");
           break;
       }
   }
   return 0;
}