Nexen v1.2.0

Major release featuring a complete Atari Lynx emulation core, 8 upstream Mesen2 bug fixes, and 13 phases of performance optimization.

Highlights

Atari Lynx Emulation (New!)

• Complete new emulation core, not a Handy fork
• 65C02 CPU, Mikey (timers/interrupts/display/audio), Suzy (sprites/math/collision)
• UART/ComLynx serial, EEPROM (93C46/66/86), RSA boot decryption
• Full debugger: disassembler, trace logger, event manager, sprite viewer
• TAS integration: piano roll, movie converter, Lua scripting
• Pansy metadata export, ROM database (~80 No-Intro entries)
• 67 benchmarks + 84 unit tests + TAS integration tests

Upstream Mesen2 Bug Fixes (8 PRs)

• SNES: DMA overflow, CX4 timing, hi-res blend, ExLoRom mapping
• NES: Open bus fix, NTSC filter dot crawl/matrix/emphasis
• Debugger: Lua crash fix, Linux Memory View performance

Performance (192 commits, 13 phases)

• FastBinary positional serializer, rewind ring buffers, audio pipeline
• Move semantics, string copy elimination, buffer reuse
• ExpressionEvaluator const ref (9x reduction), DebugHud flat buffer
• Lynx: NZ lookup table, branchless flags, timer mask optimization

Testing

• 1,495 tests across 100 suites (was 659 in v1.1.0)
• 65C02 exhaustive CPU tests, Lynx hardware reference tests
• Upstream fix verification, TAS integration tests

See CHANGELOG.md for full details.