4926316 Lisa Mmu Patent

United States Patent c191 [11) Baker et al. [45) [54) MEMORY MANAGEMENT UNIT WITH OVERLAPPING CONTROL FOR ACCESSING MAIN MEMORY OF A DIGITAL COMPUTER [75] Inventors: Paul A. Baker, Los Altos; Gary L Marten, Cupertino, both of Calif. [73] Assignee: Apple Computer, Inc., Cupertino, Calif. [21] Appl. No.: 933,071 [22) Filed: Dec. 17, 1986 Related U.S. Applicadon Data [63] [51] [52) [58) [56] Continuation of Ser. No. 426,869, Sep. 29, 1982, abandoned. Int. a.s ................................................ G06F 9/00 U.S. CL ................................. 364/200; 364/238.4; 364/246; 364/246.3; 364/246.4; 364/246.5; 364/245.4 Field of Search ................................ 364/200, 900 References Oted U.S. PATENT DOCUMENTS 3,828,327 8/1974 3,902,163 8/1975 4,004,278 1/1977 4,037,215 7/1977 4,084,224 4/1978 4,084,227 4/1978 4,084,228 4/1978 4,096,568 6/1978 4,104,718 8/1978 4,130,867 12/1978 4,297,743 10/1981 4,316,245 2/1982 4,354,225 10/1982 4,376,297 3/1983 4,378,591 3/1983 4,410,941 10/1983 4,424,561 1/1984 Berglund et al................. 340/172.5 Amdahl et al ................... 340/172.5 Nagashima ....................... 340/172.5 Birney et al........................ 364/200 Appell et al........................ 364/200 Bennett et al....................... 364/200 Dufond et al ....................... 364/200 Bennett et al....................... 364/200 Poublan et al...................... 364/200 Bachman et al .................... 364/200 Appell et al........................ 364/200 Luu et al............................. 364/200 Frieder et al....................... 364/200 Anderson et al ................... 364/200 Lemay ................................. 364/200 Barrow et al....................... 364/200 Stanley et al....................... 364/200 FOREIGN PATENT DOCUMENTS 0040702 2/1981 190324 12/1982 1413739 11/1975 1477977 6/1977 1487078 9/1977 1498116 1/1978 1547382 6/1979 European Pat. Off.. New Zealand . United Kingdom . United Kingdom . United Kingdom . United Kingdom . United Kingdom . Patent Number. Date of Patent: 1557121 12/1979 1577592 10/1980 1585960 3/1981 2073458 2/1984 4,926,316 May 15, 1990 United Kingdom . United Kingdom . United Kingdom . United Kingdom . OTHER PUBLICATIONS Wescon Conference Record, vol. 25, Sep. 1981, pp. 1-9, El Segundo, U.S.; S. Walters: "Memory Management Made Easy with the Z8000". Electronic Design. vol. 29, No. 17, Aug. 1981, pp. 115-121, Waseca, MN, U.S.; D. L. Collins et al.: "Memory Management Chip Masters Large Data Bases". Electronics International, vol. 54, No. 11, Jun. 1981, pp. 134-138, New York, U.S.; J. Beekmans et al.: "Chip Set Bestows Virtual Memory on 16-bit Minis". Primary &aminer-Gareth D. Shaw Assistant Examiner-John G. Mills Attomey, Agent, or Firm-Blakely, Sokoloff, Taylor & Zafman [57) ABSTRACT An improved memory management unit (MMU) for interfacing between a CPU and a main computer memory. The MMU receives logical addresses from the CPU and converts a portion o…