Wrong address range for custom IP in SOPC

The addresses shown in SOPC builder are byte addresses. In your C code, components are also accessed using byte base addresses.

However, components are at a low level accessed by the word. The LSB's of the byte address are always assumed to be zero which is why you don't need enough address lines for each byte in the range. The physcial address port uses word addresses.

If a master needs to read less than one word, then the byte_enable signals come into play. However, I am fairly new to this myself, so I don't know exactly how this works. I also have no experience with using 64 bit words, so I am not 100% sure how that will play into you situation.