SMALL RECONFIGURABLE
PROCESSOR FOR A VARIETY OF
DATA PROCESSING APPLICATIONS
 Inventors: Michael M. Maimer, Jr., Livonia;
Cornelius C. Perkins, Birmingham;
Donald W. Waldenmayer, Novi;
Patrick J. drowning; Leonard R.
Gardner, both of Clawson, all of
 Assignee: Burroughs Corporation, Detroit, Mich.
 Filed: Oct. 19,1970  Appl. No.: 81,786
 U.S. CI 340/172.5
 Int.CI G06I9/16
 Field of Search 340/172.5
 References Cited
UNITED STATES PATENTS
3,599,176 8/1971 Cordero, Jr 340/172.5
3,651,475 3/1972 Dunbar, Jr 340/172.5
3,579,192 5/1971 Rasche 340/172.5
3,593,313 7/1971 Tomaszewski 340/172.5
3,248,528 4/1966 Campeall 340/Campeau
3,300,764 1/1967 Doelzetal 340/172.5
An improved microinstruction data processor capable of operating as an independent processor or as a terminal unit for a large general purpose computer employing a read/write disk memory to hold both macroinstructions and microinstructions, wherein the microinstructions implement macroinstructions. The memory has a macroinstruction portion and a microinstruction portion having a changeable boundary therebetween to accomodate a variable number of microinstructions. A push-down stack facilitates microprogram branching and returning by holding microinstruction return addresses when microinstructions call for branching to microprogram subroutines. A microinstruction decoding register augmented with a microinstruction buffer register decodes a previously fetched microinstruction while a new microinstruction is fetched from memory.
3 Claims, 11 Drawing Figures