Kotlin Language Features Related to Null Handling

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Any software engineer with a Java background would find the null handling features in the Kotlin language interesting. Let's summarize this topic with some examples. Nullable types: In Kotlin, types are non-nullable by default. If you want a variable to be able to hold a null value, you need to explicitly declare its type as nullable using the Type? syntax. For example, String? denotes a nullable string, while String represents a non-nullable string. Safe calls (?.): Kotlin introduces the safe call operator (?.) for handling nullable types. It allows you to safely invoke a method or access a property on a nullable object. If the object is null, the expression returns null instead of throwing a NullPointerException. Example: data class Person(val name: String, val age: Int, val address: String?) fun main() {     // Create a person with a nullable address     val person1 = Person("John Doe", 25, "123 Main Street")     val person2 = Person("Jane Doe", 30,...
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SimpleScalar Simulator - Part 3

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Problem: Can you detect when current page is left for the instruction stream?

Inside cache.c we know if the hit is fast (same block) or slow.

/*cache.c  line 533*/
printf("Cache tagset: %d  Last tagset: %d\n", CACHE_TAGSET(cp, addr), cp->last_tagset);

   /* check for a fast hit: access to same block */
  if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
    {

       printf("Same block hit!\n");

       /* hit in the same block */
      blk = cp->last_blk;
      goto cache_fast_hit;
    }

 printf("Slow hit or miss!\n");

Before cache access, we control the nature of the access and set the iTLB power mode:

          if (itlb)
  {

    if (CACHE_TAGSET(itlb, IACOMPRESS(fetch_regs_PC)) == itlb->last_tagset) {
       low_power = 1;
       ++low_power_count;
   } else {
                low_power = 0;
                ++normal_power_count;
   }

    printf("Low count = %d, normal count = %d\n", low_power_count, normal_power_count);

             printf("Low power ratio: %f\n", (double)low_power_count / (low_power_count + normal_power_count));

      /* access the I-TLB*/
     tlb_lat = cache_access(itlb, Read, IACOMPRESS(fetch_regs_PC), NULL, ISCOMPRESS(sizeof(md_inst_t)), sim_cycle, NULL, NULL);
  
printf("Address is: %d  Size is: %d  Cycle is: %d\n", IACOMPRESS(fetch_regs_PC), ISCOMPRESS(sizeof(md_inst_t)), sim_cycle);

After running my hello.c program, the result is:

Low count = 9010, normal count = 159
Low power ratio: 0.982659



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