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Henrik RydgårdandClaude Opus 5.5
2b530dfa3b
Measured on hardware (ppsspp-re geprobe exp177-202, docs/ge-texture-cache.md): 64 lines of 16 bytes x 8 rows in 16 sets of 4 ways, LRU, the set index split between column and band bits by texel size. A line is tagged by its position in the texture and its mip level only, so another texture read without TEXFLUSH gets the first one's bytes where their lines coincide; lines load raw bytes on first read and nothing but TEXFLUSH drops them, not rendering into the texture, block transfers or CPU writes. TexCache steps every textured primitive through that, in submission order, from its texel footprint. A line remembers where it came from and its bytes are copied only before that memory changes (drawing, block transfers, copies, and anything at all when the CPU is about to run). While every line is from the one texture read since TEXFLUSH and nothing has been copied, nothing read can differ from memory, so primitives only log what they read, and TEXFLUSH usually drops the log unread. A primitive that reads bytes differing from memory, or draws over what it reads, is drawn alone from its texture with what it read from the cache laid over memory. That replaces SelfTextureSnapshot and its "fits in 8 KB" rule. All the cache experiments match the PSP exactly except exp177, which samples a block transfer's destination without TEXSYNC. Within a primitive this still loads every line before it draws; the GE loads them as it rasterizes (serpentine rows, writes reaching memory a 16-byte block late), which Split Second's blur (the one dump that changes) depends on. About 2% slower in Tekken 6 and God of War. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>