Abstract: Described herein are techniques to provide read and write barriers for flexible and efficient garbage collection. A memory heap is split into pages. Each page is aligned to an address that is a multiple of a particular power of two. When generating read and write operations, code is generated to execute the write barrier or the read barrier. At this point, the page alignment for each pointer is known; for example, if the page alignment is the same for all pointers in the system. With this page structure, it is possible to find the page start by masking the address of any heap allocated object on the page with a mask based on the page alignment (bitwise-and operation). A plurality of flags are established on a page. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.