Claude 6561daff35 linker: gate default smiley CHR tile on __default_sprite_used marker ... Drop the built-in smiley from CHR tile 0 unless something in the program actually references it. The marker fires when either: 1. `IrOp::DrawSprite` lowering falls back to tile 0 because the sprite name doesn't resolve to a user declaration, or 2. The same lowering sees a runtime `frame:` override (which could index any tile, including 0). A third source of dependency — a background nametable entry of 0 — is detected in the linker by scanning `bg.tiles` for zeros. This preserves the smiley for programs like `examples/friendly_assets` that use tile 0 as a background placeholder, even though their draws resolve to user-declared sprites. Programs whose draws all resolve to explicitly-declared sprites with static frames AND whose backgrounds reference tiles 1+ now leave CHR tile 0 as an all-zero blank, freeing 16 CHR bytes that the user can treat as an always-transparent background tile. Verified against the current example set: `sprites_and_palettes` and `auto_chr_background` reclaim tile 0; every other example keeps it (either they fall back to tile 0 via an undeclared draw name or their background tilemap references tile 0). All 33 emulator goldens still pass — removing an unreferenced CHR tile can't change observable output. https://claude.ai/code/session_016kM6P7PukktBDqTZexrrAN		2026-04-16 21:15:09 +00:00
..
emulator	linker: skip default palette + rendering enable for non-visual ROMs	2026-04-16 21:15:08 +00:00
integration
integration_test.rs	linker: gate default smiley CHR tile on __default_sprite_used marker	2026-04-16 21:15:09 +00:00