Question

The bits of CR3, that are always zero are

(a) higher 4 bits

(b) lower 8 bits

(c) higher 10 bits

(d) lower 12 bits

I got this question by my school teacher while I was bunking the class.

Enquiry is from Paging in section 32-bit Processors-80386, 80387 and 80486 of Microprocessor

Answer 1

Right answer is (d) lower 12 bits

To explain: The lower 12 bits of CR3 are always zero to ensure the page size aligned with the directory.