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公开(公告)号：CA1226957A
公开(公告)日：1987-09-15
申请号：CA481598
申请日：1985-05-15
Applicant: IBM
Inventor： BRADLEY DAVID J , OTT WILLIAM B
Abstract: INTERRUPT LEVEL SHARING An interrupt interface circuit for interrupt level sharing comprising a pulse generator having an open-collector or tri-state output connected to an external interrupt line shared by other similar circuits. An active internal interrupt signal causes the pulse generator to pulse. The external interrupt line is fed back and latched on a disabling input of the pulse generator so that any pulse on the external interrupt line prevents further pulsing. The software handler of the interrupt, upon servicing an interrupt of the interrupt level, causes the enabling of the pulse generators of that level, thereby permitting active internal interrupt signals to produce a further pulse. By this interrupt level sharing, phantom interrupts are eliminated and servicing overhead is mimimized.
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公开(公告)号：CA1184326A
公开(公告)日：1985-03-19
申请号：CA405397
申请日：1982-06-17
Applicant: IBM
Inventor： BRADLEY DAVID J
Abstract: : Apparatus and Method for Scrolling Text and Graphic Data in Selected Portions of a Graphic Display An apparatus and method for scrolling windows of both graphic and graphic encoded text information on a raster scan display. The apparatus includes a processor which references a program store, and a video refresh buffer, the buffer containing graphic and graphic encoded text data in a pixel format adapted for directly refreshing the display. The processor is operated under control of the program store and responsive to information specifying the pixel locations of opposite corners of a window to be scrolled and the number of rows to be scrolled for calculating the size and location in the display refresh buffer of the window o be scrolled, and for moving the number of rows to be scrolled from source locations to destination locations within the window in the display refresh buffer.
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