Boots – shoes – and leggings
Patent
1990-08-27
1992-07-07
Fleming, Michael R.
Boots, shoes, and leggings
3642808, 3642412, 364941, G06F 1322
Patent
active
051290642
ABSTRACT:
The system and method of this invention allows a simulated processor to receive an interrupt request from I/O devices. A simulated interrupt controller routine determines whether to post an interrupt to the simulated CPU. The simulated interrupt controller routine posts an interrupt to the simulated CPU by updating one byte, which is owned by the simulated interrupt controller, of a two byte halfword. The other byte is owned by the simulated CPU and is updated by the simulated CPU when its internal interrupt enabled state changes. Each byte of the two byte halfword is updated independently, but is loaded by the simulated CPU with only one instruction to determine if an interrupt should be acknowledged.
The simulated CPU minimizes the overhead of polling for an interrupt by performing a graph analysis of the instruction flow of control to determine the locations to poll for interrupts. The simulated CPU polls for an interrupt when an instruction transfers control dynamically, once around a loop, and when an instruction changes the interrupt enabled state of the simulated CPU.
REFERENCES:
patent: 2907524 (1959-10-01), Cali
patent: 4031517 (1977-06-01), Hirtle
patent: 4106091 (1978-08-01), Hepworth et al.
patent: 4370709 (1983-01-01), Fosdick
patent: 4400769 (1983-08-01), Kaneda et al.
patent: 4438492 (1984-03-01), Harmon, Jr. et al.
patent: 4470111 (1984-09-01), Jenkins et al.
patent: 4638423 (1987-01-01), Ballard
patent: 4695945 (1987-09-01), Irwin
patent: 4799148 (1989-01-01), Nishioka
patent: 4812967 (1989-03-01), Hirosawa et al.
patent: 4843541 (1989-06-01), Bean et al.
patent: 4860190 (1989-08-01), Kaneda et al.
patent: 4885681 (1989-12-01), Umeno et al.
patent: 4887202 (1989-12-01), Tanaka et al.
patent: 4930068 (1990-05-01), Katayose et al.
patent: 4975836 (1990-12-01), Hirosawa et al.
Graham, C., "Amiga's Trump Card: IBM PC Emulation", AmigaWorld, vol. 1, No. 2, Nov./Dec., 1985. pp. 34-35.
"SoftPC", Insignia Solutions, Inc., ISI SoftPC Data Sheet Rev., 3.0, Jan. 1987, 8 pages.
Warner, E., "Unix-Based Workstations to Run DOS", Info World, Jul. 6, 1987, p. 8.
de Nicholas Arturo M.
Fogg, Jr. Richard G.
O'Quin, III John C.
Fleming Michael R.
International Business Machines - Corporation
McBurney Mark E.
Shin Christopher B.
Smith Marilyn D.
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