Design of a multi-format fixed point processing element for graphics processing

In standard 3D graphics pipeline, the stages after projection such as back-face culling and rasterization, only need fixed point arithmetic operations. But the fixed point arithmetic operation range needs to adapt in different stages of operation. Hence, we designed a multi-format fixed point processing element (PE). In this multi-format representation, the decimal point can be placed at different positions in a number. Operations on these numbers are simpler than floating point numbers and are able to meet the needs of later stages of the graphics pipeline. We are thus able to design processors smaller than those with floating point operations. In addition, we add a simple but novel interconnect communication mode in design called blocking mode and it's shown useful in experiment.