The major opcode assignments are listed in Table D1 . Instructions are shown in uppercase. Instruction classes are capitalized. Extensions of the major opcodes can be found in the tables indicated, where applicable. In the following discussions of opcode extensions the major opcode class names are shown in parentheses.
Many instructions require both a major opcode and an opcode extension to be uniquely identified.
The extension can be one to nine bits, depending on the major opcode. This group includes instructions that access the translation lookaside buffers and the caches. The extension field, e , determines whether or not the instruction traps on overflow. Figure D7 shows the formats of the unconditional branch instructions. Figure D8 shows the formats of the coprocessor load and store instructions.