How to calculate storage space according to the address of memory space
20KB here is an approximate value, not an exact value; 1. Hexadecimal subtraction: 7000h-2001h = 4fffh4ffffh = (20479) d, that is, 20479 decimal number. Note that the unit is B, and the byte is 20479b =19.999KB = 20kB1KB = 65438.