一种图形处理用的多格式定点运算器

摘要

In typical graphics rendering pipeline,the stages after projection such as back-surface culling,viewport transformation,raster-ization and pixel shading,only need fixed point arithmetic operations. But the fixed point arithmetic operation range needs to change in different stage of operation. Hence,a multi-format fixed point Processing Element ( PE) for graphics processing is designed. Such mecha-nisms of superscalar technology as dual-issue instruction word and multi-configuration pipeline are adopted when design,no general reg-isters and LD/ST operations because of direct accessing mode. Particularly,a blockbing bit is set in the instruction word for the control of interconnect communication mode,also a few format bits are set in data word for the control of multi-format fixed point data processing. Parallel processing means like Instruction Level Parallel ( ILP) and Data Level Parallel ( DLP) can be found in design of PE.%典型图形处理管线中的隐藏面消除、视窗变换、图元光栅化和像素着色等渲染阶段只需要定点运算，但是这些定点运算的数值范围需要变动。因此，设计了一种多格式定点处理单元来满足这些运算需求。设计中采用了指令双发射和多配置流水线等超标量处理机制，访存采用直接寻址，不含通用寄存器和LD/ST操作。值得一提的是，指令字中设置了阻塞标志位，用于控制互连通信模式，数据字中设置了格式标志位，用于控制多格式定点数据的处理。处理器实现了指令级并行、数据级并行等并行处理方式。