label:    mnemonic    operands    #comment

• label (optional): The colon is NOT part of the label. Must be unique within the assembly language file. Cannot be an opcode.


• mnemonic: Opcode for a MIPS instruction or directive


• operands: Other information (registers, memory addresses, values, etc.) needed by the instruction


• # comment: Anything after the # on a line is ignored by the assembler.

All MIPS instructions are 32 bits in length and consist of three types:

• R-type, which is the most common; it specifies an opcode, up to two source and one destination registers, and a shift amount for shift. It includes arithmetic and logic, shift, and register direct jump instructions.

I-type, which is used for immediate instructions. J-type, which is used for the unconditional jump instructions. Conditional branch is using I-type format.

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