megadev-scaling

Megadev scaling

Decide whether the asset and effect benefit from an ASIC-generated image. The ASIC samples a stamp map into Word RAM; it does not give a VDP sprite a rotation flag, add palette lines or display the result by itself.

• Read ASIC layouts and projection before preparing stamps,

trace lines or register values. Read the selected Megadev headers rather than inventing convenience APIs or importing SGDK types.

• Read Ownership and publication for Main/Sub leases,

completion, cached snapshots, hidden VRAM uploads and cost accounting. Its performance section explains the measured 5→30 image/s improvements and how to profile copying, HUD work and handoff delays without weakening correctness.

• Read Validation for math, compiled adapters, ares and

checks that still need a physical console.

Essential contracts:

• The graphics operation requires 2M Word RAM and Sub ownership. Build immutable

source/map/trace inputs before writing the start register. No CPU modifies them or hands away Word RAM while the ASIC is active.

• Wait for hardware completion, then confirm the ownership handoff. A matching

mailbox reply alone does not authorize a Main read. Timeouts report failure; they do not cancel hardware or make a pending buffer safe to reuse.

• Validate alignments, region extents, image dimensions, signed step ranges and

the selected stamp/map layout. Keep output separate from source/map/trace.

• Treat the inverse projection and its fixed-point units explicitly. Floor

perspective uses a different start/step per output line; this is an image sampler, not a polygon engine, depth buffer or general camera system.

• Budget trace generation, ASIC work, Main copying, VRAM residency and VBlank

transfers separately. Publish an image only after every staged chunk completes. Extra RAM/VRAM can avoid visible tearing, but they are not free.

• Share the game's existing memory, Main/Sub, renderer and interrupt owners.

This skill does not introduce a competing CD, audio, allocator or input system.

The standalone Scaling Lab demonstrates zoom, rotation and a repeating perspective floor with original native-resolution art. Its scale_* helpers and fixed profile are project code, not Megadev APIs. The mosaic, colors, controls and layout are illustrative, not a game-design template.

Use ewrogers/megadev:latest; pull it before validation and inspect its SDK source. Limit Docker containers to two CPUs. Record actual compiler/SDK revisions and separate compiled model evidence from emulator and real-hardware observations.