Task: Sum of Elements in an Array

Introduction

You will solve this exercise starting from the sum-array.asm file located in the tasks/sum-array/support directory.

In the sum-array.asm file the sum of elements in an array of bytes (8-bit representation) is calculated.

Follow the code, observe the constructions and registers specific for working with bytes. Run the code.

IMPORTANT: Proceed to the next step only after thoroughly understanding what the code does. It will be difficult for you to complete the following exercises if you have difficulty understanding the current exercise.

Sum of Elements in an Array of types word and dword

In the TODO section of the sum-array.asm file, complete the code to calculate the sum of arrays with elements of type word (16 bits) and dword (32 bits); namely, the word_array and dword_array.

TIP: When calculating the address of an element in an array, you will use a construction like:

base + size * index

In the construction above:

  • base is the address of the array (i.e., word_array or dword_array)
  • size is the length of the array element (i.e., 2 for a word array (16 bits, 2 bytes) and 4 for a dword array (32 bits, 4 bytes))
  • index is the current index within the array

NOTE: The sum of elements in the three arrays should be:

  • sum(byte_array): 575
  • sum(word_array): 65799
  • sum(dword_array): 74758117

Sum of Squares of Elements in an Array

Starting from the program in the previous exercise, calculate the sum of squares of elements in an array.

NOTE: You can use the dword_array2 array, ensuring that the sum of squares of the contained elements can be represented in 32 bits.

NOTE: If you use the construction below (array with 10 elements)

dword_array dd 1392, 12544, 7992, 6992, 7202, 27187, 28789, 17897, 12988, 17992

the sum of squares will be 2704560839.

64 Bits Sum of Squares

Compute the sum of squares of the elements from big_numbers_array.

NOTE: The sum of the array can be represented on 64 bits, but we only have 32 bits registers.

HINT: Split the sum in 2 variables (the mul operator for 32 bits multiplication).

the sum of squares will be 1610691026282151079.

Testing

To test the implementation, enter the tests/ directory and run:

make check

In case of a correct solution, you will get an output such as:

first_test                       ........................ passed ...  20
second_test                      ........................ passed ...  20
third_test                       ........................ passed ...  30
fourth_test                      ........................ passed ...  30

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Total:                                                           100/100

If you’re having difficulties solving this exercise, go through this reading material.