DESIGN AND PERFORMANCE EVALUATION OF A PIXEL CACHE IMPLEMENTED WITHINAPPLICATION-SPECIFIC INTEGRATED-CIRCUITS

The application-specific integrated circuit (ASIC) design and the perf ormance of a graphics processor that uses a pipelined-cache with FIFO memory to transfer a 3D pixel array and its z values to the frame buff er in one cycle are described in detail. The functional modules in the graphics processor include: (1) a video refresh converter, (2) a modu le that combines texture-mapped patterns onto Phong-shaded surfaces, a nd (3) a bidirectional parallel link between external devices and the frame-buffer modules. Digital differential analyzer (DDA) algorithms a nd the size of the pixel cache relative to the frame-buffer bandwidth, have been selected for good overall performance. A drawing speed of 8 ns/pixel (32 bits/pixel) or 1.2 million Phong-shaded polygons/s (100- pixel polygons, texture mapped with hidden surface removal) was achiev ed when 60-ns access-time single port DRAMs and synchronous DRAMs were used.