• specifies the operation (i.e. “behavior”) to be performed on a processor
• the set of all distinct opcodes is called the Instruction Set Architecture (ISA)
• an opcode can be represented in either:
  • symbolic (i.e. assembly language) (e.g. AND MASK1, 128)
  • binary (i.e. machine code) (e.g. 00100001100101010)

Link to original

symbolic

• is the “symbolic encoding” of opcodes
• requires an assembler to convert it into machine language
• meant for humans

Link to original

binary

• is the “bit/byte encoding” of opcodes
• can be loaded directly into a processor to be decoded and executed
• meant for computers

Link to original