Reality Coprocessor

File:N64rcp.png

Casing of the Reality Coprocessor chip

Reality Coprocessor (RCP) is one of the Nintendo 64's two main chips, alongside the NEC VR4300, a derivative of the MIPS R4200. The RCP was developed by Silicon Graphics for Nintendo, specifically for the Nintendo 64 video game console.

The RCP consists of two main components: the Reality Signal Processor (RSP) and the Reality Display Processor (RDP).

Reality Signal Processor

The RSP is a vector processor designed for high performance 3D calculations. It handles some audio and most video pre-processing of the Nintendo 64. Its capabilities include the following: real-time edge anti-aliasing, automatic load-management, texture mapping, and real-time depth buffering. The RSP has access to 4 KB of DMEM (Data Memory) and executes instructions contained within its 4 KB of IMEM (Instruction Memory), allowing 1024 instructions to be stored at any given time. These instructions are collectively referred to as microcode. Microcode may be designed to perform specific tasks such as lighting calculations or RDP display list processing. The RSP is able to transfer data to and from main memory and DMEM/IMEM using DMA.

Reality Display Processor

The RDP is programmed by the use of display lists. A display list contains a series of commands, each of variable size, which give instructions to the RDP and control its operating state. The RDP is capable of rendering shaded, textured, and depth buffered geometry to an arbitrary frame buffer in main memory. The RDP contains 4 KB of on-chip TMEM (texture memory) in which the RDP can reference up to eight textures (so-called "tiles") at any given time. The size of the available texture memory may be reduced further if using texture lookup tables (TLUT), since the high 2 KB will be used to store the lookup tables.

See also

• Nintendo 64 technical specifications