#ELIXIR OF IMMORTALITY 2 SOFTWARE#
#ELIXIR OF IMMORTALITY 2 PS2#

Cell's SPEs are restricted purely to working in their 'local-store', relying on DMA for transfers from/to main memory and between local stores, much like a scratchpad.

#ELIXIR OF IMMORTALITY 2 PS2#

Sony's PS2 Emotion Engine includes a 16 KB scratchpad, to and from which DMA transfers could be issued to its GS, and main memory.

The architecture is similar to Sony's Cell, except all cores can directly address each other's scratchpads, generating network messages from standard load/store instructions.

Adapteva's Epiphany parallel coprocessor features local-stores for each core, connected by a network on a chip, with DMA possible between them and off-chip links (possibly to DRAM).

It was possible to place the CPU stack here, an example of the temporary workspace usage.

Sony's PS1's R3000 had a scratchpad instead of an L1 cache.

SuperH, used in Sega's consoles, could lock cachelines to an address outside of main memory for use as a scratchpad.

Cyrix 6x86 is the only x86-compatible desktop processor to incorporate a dedicated scratchpad.

Fairchild F8 of 1975 contained 64 bytes of scratchpad.

#ELIXIR OF IMMORTALITY 2 SOFTWARE#

They are better implemented in embedded systems, special-purpose processors and game consoles, where chips are often manufactured as MPSoC, and where software is often tuned to one hardware configuration. Scratchpads are not used in mainstream desktop processors where generality is required for legacy software to run from generation to generation, in which the available on-chip memory size may change. They may be useful for realtime applications, where predictable timing is hindered by cache behavior. Another difference is that scratchpads are explicitly manipulated by applications. The same issues of locality of reference apply in relation to efficiency of use although some systems allow strided DMA to access rectangular data sets. They are mostly suited for storing temporary results (as it would be found in the CPU stack) that typically wouldn't need to always be committing to the main memory however when fed by DMA, they can also be used in place of a cache for mirroring the state of slower main memory. Scratchpads are employed for simplification of caching logic, and to guarantee a unit can work without main memory contention in a system employing multiple processors, especially in multiprocessor system-on-chip for embedded systems.

Another difference from a system that employs caches is that a scratchpad commonly does not contain a copy of data that is also stored in the main memory. In contrast to a system that uses caches, a system with scratchpads is a system with non-uniform memory access (NUMA) latencies, because the memory access latencies to the different scratchpads and the main memory vary. In some systems it can be considered similar to the L1 cache in that it is the next closest memory to the ALU after the processor registers, with explicit instructions to move data to and from main memory, often using DMA-based data transfer. It is similar to the usage and size of a scratchpad in life: a pad of paper for preliminary notes or sketches or writings, etc. In reference to a microprocessor (or CPU), scratchpad refers to a special high-speed memory used to hold small items of data for rapid retrieval. Scratchpad memory ( SPM), also known as scratchpad, scratchpad RAM or local store in computer terminology, is a high-speed internal memory used for temporary storage of calculations, data, and other work in progress.

Elixir of immortality 2