Comparison range: v11 release commit 83b6341 (2025-10-31, #1454) through v12 tag e1f252e (2026-03-08).

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195 commits spanning 752 files changed, with 45 802 insertions and 20 569 deletions.

The heaviest areas of change are the CfgCpu instruction pipeline, the DOS kernel and process/memory services, the entire sound stack (Sound Blaster, OPL, Adlib Gold, PC Speaker), the timer/PIT subsystem, and the debugger UI.

Dune:

• Rewritten sound emulation, full Adlib Gold support (including surround module), ported from DOSBox Staging
• Dune glitch with the CFGCPU fixed.
• Dune floppy versions freeze fixed

Known issues:

• The Dune demo glitches out

New games (fully) working now:

• Sid Meier's Civilization
• Cadaver (fixed rendering glitch issue)
• The Summonning
• F-15 Strike Eagle II
• Wizardry 7
• Where in Space is Carmen Sandiego
• Rules of Engagement 2
• Lotus 3
• Prince of Persia 2
• and many more...

Contributor
Kevin Ferrare
Stefan Hueg
LowLevelMahn
Alberto Marnetto
Bruno Martinez
Karl Lenz
Joris van Eijden
Ievgenii Meshcheriakov
Maximilien Noal

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List of pull requests in this release:

PR	Summary	Lead contributor(s)
#1486	CfgCpu AST converted to .NET Expression trees	Kevin
#1924	MCP Server for reverse engineering (stdio + HTTP/SSE transports, CPU/memory/video/audio/input tools, UI integration)	Joris van Eijden (initial implementation), Maximilien Noal (completion) - Uses the .NET 10 MCP SDK
#2053	MCP: improve tool descriptions, inline screenshots, custom tool suppliers	Joris van Eijden
#1971	HTTP server for memory read/write by other processes	Kevin (idea, inspiration from DOSBox Staging), Maximilien Noal (implementation) - Uses the Kestrel HTTP server from the .NET SDK
#1427	New PIT, PIC, OPL3, Adlib Gold, DMA, and many Sound Blaster improvements	Stefan Hueg
#1467	CfgCpu instruction correctness fixes (ENTER, LEA, Jcc, ROR, SALC, ALU alignment with DOSBox)	Stefan Hueg
#1525	Dock-based debugger window framework	Copilot
#1544	Interrupt breakpoint IP display fix	copilot-swe-agent
#1567	Conditional breakpoint expressions compiled from CfgCpu AST	Copilot
#1572	Emulation loop scheduler redesign with priority-queue event loop	Kevin
#1563	Respect EGA/VGA read mode 1 contributions per plane in the video renderer	Karl Lenz
#1601	EMS improvements and bug fixes	Copilot
#1602	RTC Clock/CMOS device, BIOS Wait handlers, DOS time/date, IVT corruption fix	Copilot
#1603	DOS CDS and DBCS structures in DOS kernel initialization	Copilot
#1604	Improved DOS Memory Manager (unlinking, allocation strategies, MCB chain validation)	Copilot
#1614	Remove old/legacy CPU classes	Kevin
#1635	Cross-platform audio: single audio thread, full SB PCM/DSP/mixer, OPL3/OPL2/dual OPL2, Adlib Gold surround, rewired PC Speaker, software mixer UI	Maximilien Noal
#1686	Full DOS process support, TSR support, PSP services	Maximilien Noal
#1774	Separate CFG node successor determination from instruction execution	Kevin
#1780	Full CP/M FCB file API for DOS INT 21h	Maximilien Noal
#1810	Minimal handler for DOS INT 2Ah	Alberto Marnetto
#1850	CPU Heavy log	Kevin
#1852	Emulator state serialization refactor; assembly listing export	Kevin
#1855	DOSBox-format ASM output for easier heavy-log comparison	Kevin
#1857	VgaBios: handle INT 10h function 0Bh for unexpected BX values	Alberto Marnetto
#1858	Fix Colonization game	Bruno Martinez
#1869	Open the same file handles as DOS does	Alberto Marnetto
#1870	Log registers in heavy log	Kevin
#1908	Replace NukedOPL3 in-tree port with NuGet package	Stefan Hueg
#1909	Ignore MSHERC.COM's INT 10h/AH=EFh	LowLevelMahn
#1947	PCM performance fix	Maximilien Noal
#1948	Display correct link type in CFG	Kevin
#1778	Preliminary single-step tests with revocation list support	Kevin
#1961	Jump arc visualization in disassembly view	Maximilien Noal
#1966	Fix CALL-to-RET link self-modifying code detection	Kevin
#1994	VGA renderer depends on emulated time; InstructionsPerSecond restored	Kevin
#2005	Event-based VGA rendering for deterministic registers and improved performance	Kevin
#2011	Allocate space for all DosSysVars	Ievgenii Meshcheriakov
#2012	Theme-aware, syntax-highlighted CFG graph rendering	Maximilien Noal
#2032	Benchmark mode: stop emulator after N cycles	Kevin
#2040	VGA horizontal pixel panning (AR13 smooth scrolling)	Copilot

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• MCP Server for reverse engineering (#1924, Joris van Eijden / Maximilien Noal): Model Context Protocol server with stdio and HTTP/SSE transports. Exposes CPU state, memory, video, audio, input, I/O ports, breakpoints, EMS/XMS, and CFG inspection tools. UI integration with enable/disable per-tool and port display. Custom tool supplier support (#2053, Joris van Eijden).
• HTTP server for external memory access (#1971, idea from Kevin, inspired by DOSBox Staging, Maximilien Noal): REST API for reading/writing emulator memory from external processes, with A20Gate-aware addressing, validation, and UI.
• Cross-platform audio overhaul (#1635): single audio thread, complete SB PCM/DSP/hardware-mixer emulation, SB reset delay, OPL port read/write delays, SB variant selection, OPL3/OPL2/dual OPL2, Adlib Gold music and surround effects, rewired PC Speaker, and a full software mixer UI.
• CPU Heavy log and ASM output (#1850, #1855, #1870, Kevin / Kevin Ferrare): heavy-log mode records register state per instruction; DOSBox-compatible ASM output format added for easier side-by-side comparison.
• Emulator state serialization refactor (#1852, Kevin Ferrare): save executed instructions as assembly listings; unified state export API.
• More complete AST subsystem (Kevin Ferrare): expanded CfgCpu AST and Expression-tree compilation path (#1486).
• Conditional breakpoint expressions (#1567, Copilot): breakpoints can now evaluate expressions compiled from CfgCpu AST via BreakpointConditionCompiler.
• Docking debugger framework (#1525, Copilot): debugger window uses a proper docking layout via the Dock library.
• New PIT, PIC, OPL3, Adlib Gold, DMA (#1427, Stefan Hueg): rewritten PIT/PIC with interrupt shadowing, improved DMA reliability and transfer, NukedOPL3 performance improvements, Adlib Gold surround, adaptive cycle budget.
• NukedOPL3 moved to NuGet package (#1908, Stefan Hueg): the in-tree port was replaced with a proper NuGet dependency.
• Additional 386+ instructions and exception handling (#1467, Stefan Hueg): ENTER, LEA 32-bit, Jcc displacement-width fix, interrupt shadowing for LSS, CPUID now throws CpuInvalidOpcodeException.
• Full DOS process and TSR support (#1686): DOS EXEC (load-and-execute, load-only, overlay), child PSP creation, TSR (Terminate-and-Stay-Resident), return code propagation, and associated INT 21h handlers.
• Full CP/M FCB file API (#1780): sequential/random read/write, block read/write, find first/next, delete, rename, get file size.
• DOS INT 21h AH=01h Character Input with Echo (#1781).
• DOS INT 2Ah minimal handler (#1810, Alberto Marnetto): network installation query stub.
• DOS kernel structures (#1603, #1604, Copilot): CDS/DBCS tables, MCB chain validation, allocation strategies ported from FreeDOS.
• RTC Clock/CMOS device and BIOS Wait handlers (#1602, Copilot): real-time clock, alarm, periodic interrupt, INT 15h wait function.
• EMS improvements (#1601, Copilot): additional status codes, handle limit, page-frame save area.
• Get List of Lists (#1680): INT 21h function 52h now returns the internal DOS data pointer.
• Set Typematic rate and delay (#1806): IBM PC BIOS keyboard repeat configuration via INT 16h.
• Full PS/2 controller, keyboard, and INT 9h rewrite: complete scan-code-set-1 handling, PS/2 controller commands, proper BDA flag management.
• DOS/V (Japanese DOS) INT 15h error (#1782): returns expected error code so DOS/V programs proceed normally.
• Emulation loop scheduler redesign (#1572, Kevin): priority-queue event loop decoupled from PIC; cycle-based clock reintroduced.
• CLI accepts dec/hex/bin for ProgramEntryPointSegment (#1856, LowLevelMahn).
• Ignore MSHERC.COM's INT 10h/AH=EFh (#1909, LowLevelMahn).
• Open the same file handles as DOS (#1869, Alberto Marnetto).
• VgaBios INT 10h,0Bh handling (#1857, Alberto Marnetto).

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• ENTER opcode fix.
• LEA 32-bit address truncating fix.
• Interrupt shadowing for LSS instruction.
• SALC assignment swap fix.
• Jcc parser now uses displacement width based on operand-size instead of address-size.
• 32-bit ROR uses correct modulo.
• ALU operations aligned with DOSBox behavior.
• Corruption in Dune fixed (#1490, Stefan Hueg).

• CALL-to-RET link self-modifying code detection fix (#1966, Kevin).
• ModRM parser fix (#1970, Copilot).
• Display correct link type in CFG (#1948, Kevin).

• Breakpoint handling performance regression fixed (#1491, Stefan Hueg).
• Breakpoint check performance improved (#1488, Stefan Hueg).
• Performance measurement made self-containing (#1492, Stefan Hueg).
• Performance counter restored (#1620, Kevin).
• Adlib Gold and NukedOPL performance improvements (Stefan Hueg).

• GetCurrentDirectory crash fixed (#1839).
• ModifyMemoryBlock returns correct segment in AX; CurrentSize points to first segment after allocated block.
• COM files now allocated entire available memory as DOS does.
• CloseFileOrDevice sets AL to file-handle refcount on success (#1844).
• PSP commandline encoding fixed (#1600, LowLevelMahn).
• Grp4Callback fix for DOS EXEC (#1589).
• COM loading behavior fixed (#1610).
• EXE image loading relaxed to match DOS (fixes INSECTS.EXE) (#1611).
• FindLargestFree logic fix (#1804).
• NullReferenceException in CurrentDriveIndex fixed (Ultima V, #1801).
• Dune 2 crash from DBCS table segmented address miscalculation (#1775).
• Cycles limiting restored (had been accidentally removed) (#1802).
• Invalid opcode exception no longer crashes the emulator (#1803, Kevin).
• Allocate space for all DosSysVars (#2011, Ievgenii Meshcheriakov).
• IregsFrameSize at 0 prevents stack corruption (#2035).
• DosSysVars space allocation (#2011, Ievgenii Meshcheriakov): allocate space for all DosSysVars fields.

• Alpha Waves: TSR support fix (#1854); INT 21h/4Ah specific behavior (#1867).
• Colonization: fix by Bruno Martinez (#1858).
• Civilization 1: infinite loop waiting for BDA Floppy Motor Counter (#1808).

• Keyboard lock-up with concurrent queue locks (#1617).
• KeyboardReset was called twice.
• A20Gate enabled/disabled was switched.
• Mouse driver drift prevented (#1809).
• Unimplemented INT 33h mouse commands now silently ignored (#1779).
• VGA rendering on unconstructed card prevented (#1571, Kevin).
• Video aspect ratio corrected with dynamic ScaleTransform (#1833).
• PCM performance and reliability with tick mode.
• GetFunctionalityInfo now returns real values instead of dummies (Stefan Hueg, #1487).
• Cadaver rendering fix (Respect EGA/VGA read mode 1 contributions per plane in the video renderer) (#1563, Karl Lenz).

• Memory view regression fixed (#1465).
• Multi-exe game dumps no longer share the same folder (#1422).
• Interrupt breakpoint IP display corrected (#1544).
• Step-into and EmulatorBreakpointManager exceptions fixed (#1547).
• Debugger visual glitch when reaching a breakpoint (#1851).
• Input event handling moved to emulation thread.

• CS1591 warning treated as error in prerelease workflow (#1455/#1456).
• \r constraint removed from CLI parameter parsing (#1907, LowLevelMahn).

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• Legacy CPU class removal (#1614, Kevin Ferrare): old CPU and related classes deleted.
• CFG node successor decoupled from execution (#1774, Kevin Ferrare).
• CfgCpu AST to Expression trees (#1486, Kevin).
• Emulation loop scheduler rewrite (#1572, Kevin Ferrare): decoupled from PIC, simplified with priority queue, reintroduced cycle-based clock.
• PicEventQueue renamed to DeviceScheduler (#1512).
• IO containers removed (#1619).
• IPauseHandler moved from CfgCpu to EmulatorBreakpointsManager (#1544).
• NukedOPL3 replaced with NuGet package (#1908, Stefan Hueg).
• PS/2 keyboard and INT 9h rewrite: removed goto/labels, introduced ScanCode set 1 enum, consolidated four reference fields into one class.
• Keyboard FIFO (Kevin Ferrare): replaced previous keyboard buffer with a proper FIFO.
• Breakpoint UI refactored: shared MemoryBreakpointUserControl, pure XAML bindings, ViewModel consolidation (#1485).
• Optional parameter removal, singleton elimination (#1470).
• Moved to .NET 10 (#1548).

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• Docking debugger layout (#1525): debugger window panels are now dockable/rearrangeable.
• Register UI improvements (#1845): formatting, highlighting, and theming for CPU register display.
• CfgCpu graph rendering improved (#1811): cleaner, more informative CFG visualization.
• Video aspect ratio correction (#1833): dynamic ScaleTransform bound to video-mode aspect ratio.
• Software mixer UI (part of #1635): visual mixer panel for the new audio stack.
• CPU Heavy log and ASM output panels (#1850, #1855, #1870): new log views showing register state and DOSBox-format assembly.
• Breakpoint memory-value conditions (#1485): shared user control for memory breakpoint value conditions across both Breakpoints and Memory views.
• Debugger visual fix (#1851): resolved visual glitch when hitting a breakpoint.
• Memory view regression fix (#1465).

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The following changes in Spice86.Core and Spice86.Shared may require updates in downstream override projects:

Change	PR	Impact
Old CPU and related classes removed	#1614	Any code referencing legacy CPU types must switch to CfgCpu equivalents.
PicEventQueue renamed to DeviceScheduler	#1512	Update type references.
PIT/timer subsystem reshaped	#1427	Timer, CounterActivator, Pit8254Counter, Pit8254Register removed. New types: PitTimer, IPitControl, IPitSpeaker, IWallClock, PitChannelSnapshot.
State serialization API renamed	#1852	RecordedDataReader/Writer → EmulationStateDataReader/Writer; ExecutionDump → ExecutionAddresses; ExecutionFlowRecorder → ExecutionAddressesExtractor; GhidraSymbolsDumper → GhidraSymbolsExporter; MemoryDataExporter.DumpMemory() → .Write().
FunctionCall record signature changed	#1614	IsReturnRecorded field removed; ICall/Call helper recordReturn parameter removed.
DosProcessManager reshaped	#1686	No longer extends DosFileLoader; constructor takes Stack; DosProgramSegmentPrefixTracker removed; process loading moved to internal DosProgramLoader.
DosMemoryManager constructor changed	#1604	Now takes initialPspSegment directly instead of DosProgramSegmentPrefixTracker.
EmulatorBreakpointsManager constructor expanded	#1567	Now requires IMemory and additional parameters for condition compilation.
VgaCard constructor changed	various	Takes IGuiVideoPresentation instead of IGui.
Clock class removed	#1602	Replaced by CyclesClock/EmulatedClock implementing IEmulatedClock.
CycleLimiterBase abstract class removed	#1572	CpuCycleLimiter now implements ICyclesLimiter directly.
CSharpOverrideHelper additions	various	FarRet32(), NearRet32() added; ReturnOperationsHelper exposed instead of Cpu.
DosProgramSegmentPrefix.NextSegment renamed to CurrentSize	#1686	Update field references.
DosInt21Handler constructor changed	#1686	Takes DosProcessManager instead of separate DosPspTracker/Clock parameters.

Migration: recompile override projects against v12 and resolve the renamed/removed types listed above. The biggest impact areas are in the CSharpOverrideHelper API, the move to the CFGCPU, the timer/PIT abstractions, state serialization APIs, and DOS process management.