Interactive tutorial + palette pipeline overhaul#25
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Single-page interactive tutorial (docs/tutorial.html) teaching how ChromA emulates a Game Boy on a Game Boy Advance: - Side-by-side GB/GBA hardware diagrams - Interactive register mapping (Z80 → ARM) with animated connectors - Memory map comparator with highlighted connections - Tile format conversion demo showing 2bpp bitplane interleaving - 2D scanline beam visualization with PPU mode phases - HiDPI canvas rendering for Retina displays - Tutorial link added to docs/index.html footer Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Overhauls the palette pipeline: - Remove gamma correction (5 brightness levels) and gbc_palette2 staging buffer. transfer_palette_ reads from pal_before (128-byte frame-start snapshot taken at GB line 0). - Wire up the previously dead pal_split infrastructure. ff69_w_tail records palette snapshots when the scanline changes (up to 8 splits). VCount interrupts patch PALRAM at split boundaries for mid-frame palette changes. - DMA3 always armed with counter-based mode selection: ≤4 writes/GBA-frame: 1-word PALRAM self-refresh (no-op) >4 writes/GBA-frame: 64-word per-scanline buffer replay Counter cleared at GBA VBlank to avoid 2:1 frame ratio race. - Remove line 75 palette copy (no longer needed). Hercules GBC: title screen per-scanline colors (no flicker), gameplay has correct colors. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Overhauls the palette pipeline: 1. Remove gamma correction (5 brightness levels). 2. Remove gbc_palette2 staging buffer and line 75 copy. transfer_palette_ reads from pal_before (128-byte frame-start snapshot taken at GB line 0). 3. Wire up the previously dead pal_split infrastructure. ff69_w_tail records palette snapshots when the scanline changes (up to 8 splits). VCount interrupts patch PALRAM at split boundaries for mid-frame palette changes. 4. DMA3 always armed with counter-based mode selection: - ≤4 writes/GBA-frame: 1-word PALRAM self-refresh (no-op) - >4 writes/GBA-frame: 64-word per-scanline buffer replay Counter cleared at GBA VBlank. The threshold discriminates games that tolerate EWRAM DMA per HBlank (per-scanline palette games) from those that don't (64-word EWRAM DMA overruns HBlank for normal games). This is a GBA hardware constraint, not a heuristic. Hercules GBC: title screen per-scanline colors (no flicker), gameplay has correct colors. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Replaces verbose palette delivery explanation with concise breakdown of all 4 DMA channels per HBlank (DMA0: scroll+BG 6w, DMA1: DISPCNT 1w, DMA2: WIN0H 1w, DMA3: palette 1w/64w). Explains counter-based mode selection, why 64-word can't be universal (EWRAM too slow, no source-reload), and why a counter not a flag (2:1 frame race). Event log now shows all 4 DMA channels during HBlank. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Summary
Three changes:
1. Interactive tutorial (
docs/tutorial.html)Single-page guide teaching how ChromA emulates GB on GBA:
2. Palette pipeline overhaul
gbc_palette2staging buffer and line 75 copy —transfer_palette_reads directly frompal_before(128-byte frame-start snapshot)ff69_w_tailrecords up to 8 mid-frame splits, VCount interrupts patch PALRAM at split boundaries3. Test improvements
build/chroma.elf.mapTest plan
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