A "virtual on-chip memory" that provides advantages as compared to an
on-chip memory that utilizes a cache. In accordance with the invention,
when a CPU attempts to access a memory address that is not on-chip, the
access is aborted and the abort is handled at a page level. A single page
table is utilized in which each entry constitutes an address in the
virtual address space that will be mapped to a page of on-chip memory.
The CPU obtains the missing data, updates the page table, and continues
execution from the aborted point. Because aborts are handled at the page
level rather than the line level, the virtual on-chip memory is less
expensive to implement than a cache. Furthermore, critical real-time
applications can be stored within a non-virtual portion of the memory
space to ensure that they are not stalled.