4 ms·
But is the uOp trace cache free? It surely doesn’t magically decode and put stuff in there without cost
by ozgrakkurt 1y ago
But is the uOp trace cache free? It surely doesn’t magically decode and put stuff in there without cost
- Remnant44 1y agoFor sure.. for what it's worth though, I have run across several references to arm also implementing uop caches as a power optimization versus just running the decoders, so I'm inclined to say that whatever it's cost it pays for itself. I am not a chip designer though!
- hajile 1y agoApple never used a uop cache in their designs. ARM dropped uop caches when they removed 32-bit support. Qualcomm also skipped uop cache. uop made sense with 32-bit support because the 32-bit ISA was so complex (though still simple compared to x86). Once they went to a simplified instruction design, the cost to decode every single time was lower than the cost of maintaining the uop cache.