B.2 -Instruction Notation Conventions

B FPU Instruction Set Details

B.2 Instruction Notation Conventions

In this appendix, all variable subfields in an instruction format (such as fs, ft, immediate, and so on) are shown in lower-case. The instruction name (such as ADD, SUB, and so on) is shown in upper-case.

For the sake of clarity, we sometimes use an alias for a variable subfield in the formats of specific instructions. For example, we use rs = base in the format for load and store instructions. Such an alias is always lower case, since it refers to a variable subfield.

In some instructions, the instruction subfields op and function can have constant 6-bit values. When reference is made to these instructions, upper-case mnemonics are used. For instance, in the floating-point ADD instruction we use op = COP1 and function = ADD. In other cases, a single field has both fixed and variable subfields, so the name contains both upper and lower case characters. Bit encodings for mnemonics are shown in Figure B-3 at the end of this appendix, and are also included with each individual instruction.

In the instruction description examples that follow, the Operation section describes the operation performed by each instruction using a high-level language notation.

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