(A) multithread expanded VLIW vertex processor with vertex caches

Abstract

Early implementations of the embedded mobile 3-D graphics processor mainly focused on core area and power dissipation to provide graphics functions into a SoC platform within a limited area and a power budget. After that, the demand on rapidly increasing multimedia applications, such as mobile cell-phone, PDA, and so on, initiates to develop the processing performance of the graphics processor while maintaining its power dissipation suitable for mobile systems. Recently, embedded 3-D graphics processors continuously increase their functionality as well as the processing performance and reduce the power dissipation to achieve more realism on the power or energy-limited mobile systems. In this thesis, an energy efficient floating-point vertex processor is proposed making use of not only low-power techniques but also graphics-specific characteristics to acquire higher performance as well as better power efficiency for the mobile graphics environment. It supports the up-to-dated OpenGL ES 2.0 and a high-end standard, Vertex Shader 3.0, which include the advanced functions, such as flow controls and vertex texturing. The datapath is an efficient combination of functional units for the 3-D graphics vertex processor while providing sufficient operands with limited read and write-ports to reduce the power dissipation and the excessive number of registers ports in the VLIW datapath. In the proposed datapath, a power management unit is implemented to control the state of the whole processor parts with the operand isolation and clock gating methods as well as a processor’s state-related sleep mode in on-chip memories. To reduce the bandwidth between hosts and graphics processors and to improve the vertex processing performance, vertex caches are also implemented with an optimized configuration. To give more programmability and efficiency, a vertex texture fetcher with four sampler units is implemented into the datapath, which is the first implementation on the embedde...