Abstract: An information processing device, such as a notebook computer, having a plurality of subsystems requiring power input, is provided with a switching regulator for supplying power to these various subsystems. The switching regulator is controlled by a feedback voltage which is selected to be a minimum value from amongst the various power lines present.

Abstract: A display system having a frame buffer comprising a plurality of memory planes, a display device for visually displaying images written into the frame buffer, and a controller for controlling image data operations. The display system is provided with an extended raster operation circuitry comprising an intraplane operation unit and an interplane operation unit. Operation results of the circuitry are written back to the frame buffer. The respective operation units perform operations specified by the controller. The intraplane operation unit performs operations on image data in each of the memory planes, separately, while the interplane operation unit performs operations on image data in at least two memory planes selected by the controller. There are no restrictions as to the positional relation between the intraplane operation unit and the interplane operation unit.

Abstract: Digital display data is stored in first and second memories which are accessed together to provide respective streams of picture element data groups for display on a raster scan display device. A comparator compares each data group from a selected one of the streams with a data group representing a particular color. The comparator output is applied as a control input to a multiplexer which also receives the data streams. When no equality is detected, the multiplexer passes the data groups in the compared stream through to the display device. Whenever equality is detected the multiplexer passes the corresponding data group in the non-compared stream through to the display device. The result is that the displayed image corresponding to the compared stream is made transparent at areas corresponding to the compared color, and there areas are filled in with an image corresponding to data from the non-compared stream of data.