United States Patent       5,422,998     June 6, 1995
VIDEO MEMORY WITH FLASH FILL   Margolin

Abstract

A single-chip semiconductor memory device optimized for high performance flat-shaded polygon video systems consists of a RAM with flash fill circuitry whereby the Start and End addresses are specified for a given row; the data within this range are read, modified, and written back to the memory in parallel thereby requiring a maximum of three memory cycles to fill a line segment independent of the length of the line. The data are modified according to a function between a color register and the data already present in the memory array, the functions being: AND, OR, EXCLUSIVE OR, or REPLACE.
 
 

United States Patent       5,553,229     September 3, 1996
ROW ADDRESSABLE GRAPHICS MEMORY WITH FLASH FILL   Margolin
 

This patent has the same specification as 5,422,998  but with different claims.
 
 

United States Patent       5,933,156     August 3, 1999

Z-BUFFER FOR ROW ADDRESSABLE GRAPHICS MEMORY
WITH FLASH FILL      Margolin
 

Abstract

A Z-Buffer is added to a Row Addressable Graphics Memory With Flash Fill so that a Z (or Depth) value is supplied with each Start and End address. The Z value is calculated for each pixel between the Start and End address. This value is compared to the existing Z value for that pixel stored in the Z-Buffer. Values less than the existing value replace the Z value for that pixel in the Z-Buffer and allow the new pixel to be written into the display memory. The Z data are read, modified, and written back to the Z-Buffer in parallel thereby requiring a maximum of three memory cycles to operate on a line segment independent of the length of the line.