Immediate operand

An immediate operand is a value encoded in an instruction rather than fetched from a processor register or a separate memory location. Its width and interpretation limit the available values; scaling an encoded field can trade address granularity for displacement range.

An instruction encoding that stores an eight-bit byte and a two-bit byte-position selector, expanding them to a 32-bit machine word as $b{2}^{8j}$ for $0\le j\le 3$. Four such values can construct any 32-bit constant using bitwise OR or addition modulo $2^{32}$.

Widen an $m$-bit binary representation to $w>m$ bits by retaining the original low positions and filling every new high position with zero. This preserves the unsigned interpretation. A MIPS instruction such as ori uses zero extension of its immediate operand, whereas addi uses sign extension.