1.4 Instruction Queues
The integer queue contains 16 instruction entries. Up to four instructions may be written during each cycle; newly-decoded integer instructions are written into empty entries in no particular order. Instructions remain in this queue only until they have been issued to an ALU.
Branch and shift instructions can be issued only to ALU1. Integer multiply and divide instructions can be issued only to ALU2. Other integer instructions can be issued to either ALU.
The integer queue controls six dedicated ports to the integer register file: two operand read ports and a destination write port for each ALU.