The number of things in a range can be found from the following relationship
Rich (BB code):
(Upper_Limit - Lower_Limit) + 1
Example 1 - How many integers are in the range 3 to 18?
Answer (18 - 3) + 1 = 16
Example 2 - How many addresses in the range 0x00000 to 0x7FFFF?
Answer (0x7FFFF - 0x00000) + 1 = 0x80000
Convert Hex to Decimal to find
0x80000(Hex) = 524,288 Bytes
I think you may be confusing the number of bytes in the address with the number of bytes at each address. In a byte addressable memory each address corresponds to exactly one byte. Words are located at even addresses and can be either big-endian or little-endian. Similarly long words are at addresses that are a multiple of four and again can be big or little endian