Move the emulator into crates/gba-core, the original demo programs into
crates/gba-demos, and the minifb frontend into crates/desktop. The binary
is now gameboy-rust. Imports change from gba_rust to gba_core/gba_demos;
no behavior changes.
gba-core has no dependencies. Its integration tests use gba-demos as a
development dependency.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Add SWI 0x09 and 0x0a as original ARM routines. Evaluate the fixed-point angle polynomial with wrapped products, reduce ArcTan2 ratios with integer division, and handle axes and quadrants. Require sign-extended 16-bit inputs and preserve non-result caller registers.
Add 15 regression tests for fixed-point and floating-point references, signed limits, rounding, quadrant boundaries, caller flags, stack bounds, repeated calls, and DMA/IRQ progress. Validate 671 default and 660 core-only tests in debug and release, plus all 10 native Darwin ARM64 window smoke tests.
