- A 6-bit opcode field OP
- Two 5-bit register fields A and B
- A 16-bit immediate data field IMM16
In most cases, fields A and IMM16 specify the source operands, and field B specifies the destination register. IMM16 is considered signed except for logical operations and unsigned comparisons.
I-type instructions include arithmetic and logical operations such as addi and andi; branch operations; load and store operations; and cache management operations.