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https://en.wikipedia.org/wiki/Scratchpad_memory https://en.wikipedia.org/wiki/Scratchpad_memory On the original PlayStation, the scratchpad was a PITA. You ha
by corysama 11y ago
https://en.wikipedia.org/wiki/Scratchpad_memory https://en.wikipedia.org/wiki/Scratchpad_memory
On the original PlayStation, the scratchpad was a PITA. You had to weigh the speedup against the cost of manually copying in and out the the pad. A modern implementation would copy via DMA like the PS3's Cell processors. Still a PITA, but at least the payoff for the effort can be quite good.
- nulltype 11y agoNice! This is exactly what I was thinking of, thanks for the link.
- clevernickname 11y agoCame here to post this. The other advantage of cache over explicit control of the on-chip SRAM is that it allows code to be inherently forwards and backwards compatible, rather than tying the code to a specific machine with a specific amount of on-chip memory. And I imagine the nightmare would only increase if you had to factor multitasking into an explicit scheme. The primary benefit of explicit on-chip memory is not, AFAIK, that you can manually manage it significantly better than a cache, but that it takes up significantly less die space and has lower access latency. You really see this idea shine in tiny cheap microcontrollers that have no external memory.