公开(公告)号：CA1092664A

公开(公告)日：1980-12-30

申请号：CA278844

申请日：1977-05-20

Applicant: IBM

Inventor： MITCHELL RALPH C ,  PI SHING-CHOU ,  LONG GERALD B

IPC: H01L27/112 ,  H03K19/177 ,  G11C11/40 ,  H03K19/08

Abstract: TIME SHARED PROGRAMMABLE LOGIC ARRAY This specification describes arrays for performing logic functions. In these arrays input variables are placed on a series of parallel input lines that intersect a number of parallel output lines in a grid of intersections, Field effect devices at these intersections have their gate terminals connected to one of the input lines and their source terminal connected to one of the output lines and through a load device to a source of potential. The drain terminals of these devices are either unconnected, connected directly to ground or connected to ground through one of two switching devices. The devices with unconnected drains are inoperative. The devices with their drains connected directly to ground are operative at all times. While the devices connected to ground through one of the switches are operative only when the switch is closed. The array can be time shared by two different logic functions by having one or the other of the switches off at any given time.

公开(公告)号：CA1023861A

公开(公告)日：1978-01-03

申请号：CA192695

申请日：1974-02-15

Applicant: IBM

Inventor： HOLMES ARTHUR W JR ,  LONG GERALD B ,  PADDOCK RICHARD C ,  PI SHING-CHOU ,  PRICE DONALD W

IPC: G11C17/00 ,  G06F9/26 ,  G11C11/413 ,  G11C17/12

公开(公告)号：DE3175685D1

公开(公告)日：1987-01-15

申请号：DE3175685

申请日：1981-08-28

Applicant: IBM

Inventor： BRESENHAM JACK ELTON ,  GRICE DONALD GEORGE ,  PI SHING-CHOU

IPC: G06F3/153 ,  G06K15/22 ,  G06T11/20 ,  G09G1/10 ,  G09G5/20 ,  G09G5/36

Abstract: A graphic output system generates circular arcs of lengths up to and including a full circle of 360 degrees. Nonsymmetrical closest points are located for noninteger radius and arc center values. Incremental move commands are generated for drawing an arc either in the clockwise or counter clockwise direction which is a distinct advantage when used to drive a pen type electromechanical plotter. By dividing the generation of a 360 degree arc into eight octants, only two of the original eight directions need to be considered as candidate directions toward the next integer display matrix value to be displayed. Initialization provides a simple stopping test for any circular arc of arbitrary length and direction. Only simple addition and sign testing is used to display the circular arc.

公开(公告)号：CA1187222A

公开(公告)日：1985-05-14

申请号：CA384840

申请日：1981-08-28

Applicant: IBM

Inventor： BRESENHAM JACK E ,  GRICE DONALD G ,  PI SHING-CHOU

IPC: G06F3/153 ,  G06K15/22 ,  G06T11/20 ,  G09G1/10 ,  G09G5/20 ,  G09G5/36 ,  G09G3/00

Abstract: An improved method and apparatus are disclosed for generating circular arcs of any arc length greater than zero up to and including a full circle of 360 degrees. The method and apparatus can locate nonsymmetrical closest points for noninteger radius and arc center values. The method and apparatus is capable of generating the incremental move commands for drawing an arc either in the clockwise or counter clockwise direction which is a distinct advantage when used to drive a pen type electromechanical plotter. By dividing the generation of a 360 degree arc into eight octants, only two of the original eight directions need to be considered as candidate directions toward the next integer display matrix value to be displayed. The method and apparatus employ a novel initialization which provides a simple stopping test for any circular arc of arbitrary length and direction. Only simple addition and sign testing is used to display the circular arc.