CS2104 Vanilla Assembly Language Linked List

gistfile1.c

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

/* gobal declarations */
int eax, ebx, ecx, edx, esi, edi;
unsigned char M[10000];
int a[5];

/* prototypes */
void exec();

int main ()
{
    /* declarations */
    srand(time(NULL));
    a[0] = 5;
    a[1] = 2;
    a[2] = 4;
    a[3] = 21;
    a[4] = 5;

	/* Assignment of array to M[]
	Srand is used to generate random address and may cause clashes, but
	that is quite improbable. */
    int curr = rand() % 10000;
    *(int *)&M[curr] = a[0]; // initial value
    int next = rand() % 10000; // randomly generate next address
    *(int *)&M[curr+4] = next; // assignment of next add to initial node

    esi = curr; // initial address
    curr = next;

    int i;
    for (i=1; i<=5; i++)
    {
        *(int *)&M[curr] = a[i];
        next =(i == 5) ? 0 : rand() % 10000;
        *(int *)&M[curr+4] = next;
        curr = next;
    }

    // Execute VAL code
    exec();
    printf("result = %d\n", eax);
	return 0;
}

void exec()
{
    eax = 0;
loop:
    ebx = *(int *)&M[esi]; // assign value of node to ebx
    eax += ebx;
    esi = *(int *)&M[esi+4]; // address of next node
    if (esi < 1) goto endloop; // end condition: esi < 1
    goto loop;
endloop:{}
}