(Mill team) The streams are not streams of instruction; they are streams of half-instructions. The Mill is a wide-issue machine, like a VLIW or EPIC; each instr

(Mill team) The streams are not streams of instruction; they are streams of half-instructions. The Mill is a wide-issue machine, like a VLIW or EPIC; each instruction can contain many operations, which all issue together. Each instruction is split roughly in half, with some of the ops in one half and some in the other. On the Mill, the split is based on the kind of operation and the info that ikt needs to encode: all memory and control flow ops on one side, all arithmetic on the other, although other divisions are possible. Each half is grouped with the same half of other instructions to make a stream, and the two streams decode together, step by step, so each cycle one instruction, comprising both halves, decodes and issues. The result is to double the available top level instruction cache, and cut in half the work that has to be handled by each of the two decoders.