This test detects memory aliasing. Memory aliasing exists when a physical memory block repeats one or more times in a logical memory space. Without knowing about this condition, you might conclude that there is much more physical memory than what actually exists.
The address test uses a simplistic technique to detect memory aliasing. The test writes sequentially increasing data values (starting at one and increasing by one) to each successive memory location. The maximum data value is a prime number and its specific value depends on the addressing mode so as to not overflow the memory location.
The test uses a prime number of elements to avoid coinciding with binary math boundaries:
If the test reaches the maximum value, the value rolls over to 1 and starts incrementing again. This sequential pattern repeats throughout the memory under test. Then the test reads back the resulting memory and verifies it against the written patterns. Any deviation from the written order could indicate a memory aliasing condition.