Abstract: A queuing mechanism is described for managing packets between agents of a computer system. The queuing mechanism includes an ordered queue including a plurality of queue registers to store a plurality of packets. The queuing mechanism also includes a bypass queue coupled to the ordered queue, wherein, if a packet at head of the ordered queue is a delayed request and is stalled for lack of flow control credit, then the stalled packet is moved into the bypass queue.

Abstract: A computer graphics technique for rendering shaded areas by using pseudo-random noise localized to image boundaries is disclosed. Calculated pixel values are initially generated using an arithmetic accuracy larger than the word size of an associated bitmap memory. The calculated pixel values thus have a most significant portion, corresponding to the portion which is to be stored in bitmap memory, and a least significant portion, corresponding to the additional accuracy. Pseudo-random noise, preferably generated by a linear feedback shift register, is then added to some or all of the least significant portion, and the carry output from this operation is added to the most significant portion. The most significant portion is then written into bitmap memory. Changes in the value of the integer portion thus occur with increased frequency as the distance to an intensity boundary decreases, since the random noise causes the dithering to occur with increased frequency.

Abstract: Method and apparatus for rendering a smooth-shaded graphics primitive vertical series of horizontal pixel spans which extend between beginning and trailing edges of the primitive, the pixel locations being spaced from each other by selected distances dX and dY. The apparatus produces X and Y addresses of the first and last pixels in the beginning span of the primitive and the number of spans in the primitive. Also produced are step values (dX/dY) indicating the slopes of the beginning and trailing edges, and a beginning intensity value for the first pixel in the beginning span. DX is added to the X address of each pixel in each span to determine the X address of the next pixel in that span and one of the step values is added to the X address of the first pixel in each span to calculate the X address of the first pixel in the next span of the primitive.