Fix/civilization

[maximilien-noal]

Description of Changes

Removes regression from commit 5b8a876 which broke Civilization.

Rationale behind Changes

Fixes Civilization :

Makes us stick to FreeDOS kernel behavior regarding FindFirst and FindNext

Suggested Testing Steps

Tests updated accordingly. They all pass. Tested manually with Civilization.

[Copilot]

Pull request overview

This PR (titled "Fix/civilization", presumably for the Civilization DOS game) refactors DosFcbManager's public FCB entry points to take SegmentedAddress instead of pre-computed uint linear addresses, and updates the only caller (DosInt21Handler) accordingly. It also inlines the two previously-extracted FCB log helpers and rewords a few XML doc summaries / the implementation-reference paragraph. The PR description is empty, so the specific Civilization-related symptom and fix rationale are not documented.

Changes:

• Change every FCB-related method signature in DosFcbManager (e.g. OpenFile, CloseFile, SequentialRead/Write, RandomRead/Write, RandomBlockRead/Write, ParseFilename, GetFcb, etc.) from uint fcbAddress to SegmentedAddress fcbAddress, converting back to a physical address inside via MemoryUtils.ToPhysicalAddress(seg, off) (which is the same computation as SegmentedAddress.Linear).
• Update all call sites in DosInt21Handler to pass the SegmentedAddress directly instead of .Linear.
• Inline the LogFcbWarning / LogFcbDebug private helpers into ~35+ duplicated if (IsEnabled) { _loggerService.Warning/Debug(...) } blocks, and tweak a few XML doc strings.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/Spice86.Core/Emulator/OperatingSystem/DosFcbManager.cs	FCB API now takes SegmentedAddress; address converted via MemoryUtils.ToPhysicalAddress; log helpers inlined; some doc comments reworded but <param> docs still say "Linear address".
src/Spice86.Core/Emulator/InterruptHandlers/Dos/DosInt21Handler.cs	All FCB call sites updated to pass fcbAddress / stringAddress directly instead of .Linear.

Comments suppressed due to low confidence (2)

src/Spice86.Core/Emulator/OperatingSystem/DosFcbManager.cs:1213

• MemoryUtils.ToPhysicalAddress(fcbAddress.Segment, fcbAddress.Offset) is computed identically to SegmentedAddress.Linear (both do segment << 4 + offset, see SegmentedAddress.cs:22 and MemoryUtils.cs:20). The repeated explicit call adds verbosity without changing behavior — using fcbAddress.Linear would be clearer and consistent with the rest of the codebase. Note that switching to ToPhysicalAddress does NOT address the segment-rollover concern described in the codebase guidelines, since the formula is identical. If the intent of this refactor was to handle rollover correctly, an MMU-based translation (IMmu.TranslateAddress) should be used instead. This pattern is repeated throughout GetFcb and GetActualFcbBaseAddress.

    private uint GetActualFcbBaseAddress(SegmentedAddress fcbAddress) {
        // Extended FCB detection via drive marker 0xFF
        DosFileControlBlock probe = new DosFileControlBlock(_memory, MemoryUtils.ToPhysicalAddress(fcbAddress.Segment, fcbAddress.Offset));
        if (probe.DriveNumber == 0xFF) {
            return MemoryUtils.ToPhysicalAddress(fcbAddress.Segment, fcbAddress.Offset) + DosExtendedFileControlBlock.HeaderSize;
        }
        return MemoryUtils.ToPhysicalAddress(fcbAddress.Segment, fcbAddress.Offset);
    }

src/Spice86.Core/Emulator/OperatingSystem/DosFcbManager.cs:301

• Inlining the previous LogFcbWarning / LogFcbDebug helpers duplicates the same if (_loggerService.IsEnabled(...)) { _loggerService.Warning/Debug("FCB {Operation} ...", ...) } block roughly 35+ times. The deleted helpers (former lines 1374–1383) were a clean, low-cost abstraction that ensured a consistent log format and consistent IsEnabled gating. Reintroducing them (or keeping them) would substantially reduce noise in this file and avoid future drift between log call sites. Consider keeping the helpers.

            if (_loggerService.IsEnabled(LogEventLevel.Warning)) {
                _loggerService.Warning("FCB {Operation} failed at 0x{Address:X} because {Reason}", "OPEN", baseAddr, "Blank filename");
            }
            return FcbStatus.Error;
        }

        DosFileOperationResult result = _dosFileManager.OpenFileOrDevice(fileSpec, FileAccessMode.ReadWrite);
        if (result.IsError || result.Value == null) {
            if (_loggerService.IsEnabled(LogEventLevel.Warning)) {
                _loggerService.Warning("FCB {Operation} failed at 0x{Address:X} because {Reason}", "OPEN", baseAddr, "OpenFileOrDevice failed");
            }