65C816

The WDC 65C816, sometimes abbreviated as 65816, is the main CPU used for the SNES, as part of its S-CPU chip.

See: 65c816 guides

Links

 * 65C816 Opcodes - 6502.org article, reference for 65C816 relative to 6502.
 * 65816 Reference - Superfamicom.org wiki article, general reference for 65816 and instruction set.
 * 6502 Guide - Archived Obelisk 6502 guide, good primer for the CPU family.
 * W65C816S.PDF - Official datasheet for WDC 65C816 CPU.