How is an array stored in memory
 

This material is mostly for review -- so I'll go over them quickly

 

The array elements of an array are stored contiguously in memory without gaps:

 

Because:

  • When the first array element meets the alignment requirement, all subsequent element will also meet it

How to store a byte typed array
 

A byte (typed) array uses 1 byte to store each of its array element

How a byte typed array is stored in memory:

 

Remember: There are no gaps between array elements !

How to store a short typed array
 

A short (typed) array uses 2 bytes to store each of its array element

How a short typed array is stored in memory:

 

Remember: There are no gaps between array elements !

How to store a int typed array
 

A int (typed) array uses 4 bytes to store each of its array element

How an int typed array is stored in memory:

 

Remember: There are no gaps between array elements !

Array used in CS255 ARM assembler programming

  • Recall that there are 2 types of arrays:

    Static array   (C) Dynamic array   (Java)
    The array variable (A) is a (symbolic) constant for the location (= address) of the array The array variable (A) is a reference variable that contains the base address of the array

Array used in CS255 ARM assembler programming

  • We will use static arrays in ARM assembler programming (just like C):

  • Base address:

    • Base address of an array = the start location of the array

  • The base address of the (static) array will be marked by a label (= symbolic constant) that cannot be change (= "static")