MIPS Assembly/Memory Instructions
Load and store instructions use a special syntax:
instr rt, imm(rs)
The memory address used for the load or store is rs + imm. The immediate is sign-extended.
Loads a byte and does not sign-extend the value.
Loads a halfword, or two bytes, and does not sign-extend the value. The halfword must be aligned (i.e., it must start at an even address).
Loads a word (four-bytes) from memory. The word must be aligned (i.e., the last two bits of the address must be zero).
Stores the least significant (rightmost) byte of rt to memory.
Stores the least significant (rightmost) halfword of rt to memory.
Stores the contents of rt in memory.