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Operand Sizes

MIPS instructions can manipulate different-sized operands
  • single bytes,   two bytes ("halfword"),   four bytes ("word")
Many instructions also have variants for signed and unsigned

Leads to many opcodes for a (conceptually) single operation, e.g.

  • lb ... load one byte from specified address
  • lbu ... load unsigned byte from specified address
  • lh ... load two bytes from specified address
  • lhu ... load unsigned 2-bytes from specified address
  • lw ... load four bytes (one word) from specified address
  • la ... load the specified address
All of the above specify a destination register