Patents Examined by Than J. Nguyen
  • Patent number: 5734857
    Abstract: In order to expand the address range of the program counter in a microprocessor, a register is provided as an additional special-function register which actually consists of two separate registers which are connected in series. One register supplies the most-significant address bits via an AND-gate and is also coupled to the internal data bus. The register contents are automatically changed when the program counter passes the end position or the starting position. In the case of program jumps, the old contents of the register are also stored in the stack; this requires only few additional instructions from the standard instruction set. In the case of an interrupt, the AND-gate is blocked, so that automatically the first segment of the program memory with the interrupt programs is addressed. A linear expansion of the program address range is thus achieved without degrading the compatibility.
    Type: Grant
    Filed: November 29, 1994
    Date of Patent: March 31, 1998
    Assignee: U.S. Philips Corporation
    Inventor: Gerald Gaubatz
  • Patent number: 5699539
    Abstract: A virtual memory system and method enable a computer system to use a virtual memory address space larger than the size of physical primary memory while swapping few, if any, pages out to secondary memory. Primary memory is divided into a work space, used for storing uncompressed pages in current use, and a "Compression Heap". A MappedOut storage space, which includes the Compression Heap and a portion of secondary memory, is used to store all pages swapped out of the work space. A virtual memory manager dynamically determines the number of pages of primary memory which need to be included in the work space, and moves pages of primary memory into the work space from the Compression Heap as needed. Pages are selected to be swapped out of the work space to the MappedOut storage space on the basis of memory usage data.
    Type: Grant
    Filed: May 7, 1996
    Date of Patent: December 16, 1997
    Assignee: Connectix Corporation
    Inventors: Jonathan Forrest Garber, Jorg Anthony Brown, Chad Perry Walters