Reality Coprocessor

The Reality Coprocessor, or RCP, is one of the two main processors on the Nintendo 64 board. Split into two components, the Reality Signal Processor and Reality Display Processor, it cooperates with the other main processor, the VR4300 CPU to draw 3D graphics, perform matrix calculations, and produce audio. The RCP is also connected to the onboard RDRAM, providing direct access to memory.

N64 RCP Decapped
N64 RCP Decapped

RCP Interface

RCP is the core component of the N64 architecture. It is connected to all other peripherals (VR4300, ROM, RDRAM), and handles communications in all directions. For instance, VR4300 must go through RCP to access RDRAM. RCP is thus in charge of implementing the full VR300 Memory Map.

Please check VR4300 interface for a detailed description of the bus between the CPU and the RCP at the electric level.

RSP

The Reality Signal Processor, or RSP, is the portion of the RCP responsible for matrix math, lighting calculations, clipping, shading, and other highly parallel graphics tasks as well as audio processing. It is a programmable MIPS processor with a custom set of SIMD instructions for vectorized fixed point operations (exposed as COP2 -- a group of reserved instructions in the standard MIPS instruction set). The RSP is also able to directly drive the RDP (the hardware rasterizer) by accessing its registers, so that it can terminate the graphic pipeline by telling the RDP to draw triangles into the framebuffer.

RDP

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