dc3-pair

name	dc3-pair
description	Find DC3 reference implementation for an RB3 unit. Shows function overlap, DC3 match status, and optionally the DC3 source code. Use to leverage DC3's ~87% complete decomp for shared Milo engine code.
argument-hint	[unit-name] [--source]
allowed-tools	Bash(python3 *), Read, Grep, Glob

DC3 Pair Skill

Find the corresponding DC3 source file for an RB3 unit and show compatibility info. DC3 and RB3 share the Milo engine -- most system/ code is similar or identical.

Arguments

$ARGUMENTS - An RB3 unit name (e.g., CharBones, system/char/CharBones). Add --source to include the full DC3 source code.

Steps

1. Find the DC3 source file for the given RB3 unit:

   python3 scripts/dc3_compare.py --filter "$ARGUMENTS" --sort rb3
   

   This shows functions that DC3 has at 100% that RB3 can potentially port.

2. If --source is requested, read the DC3 source file:

   • DC3 source is at /home/free/code/milohax/dc3-decomp/src/system/
   • Map the RB3 unit path to DC3: system/char/CharBones -> /home/free/code/milohax/dc3-decomp/src/system/char/CharBones.cpp

3. For a unit summary showing which files have the most DC3-ported potential:

   python3 scripts/dc3_compare.py --units --filter system/
   

4. For very low match functions that DC3 has solved:

   python3 scripts/dc3_compare.py --filter system/ --max-rb3 50 --sort rb3
   

DC3 vs RB3 Differences

When porting DC3 code to RB3, watch for:

• Name mangling: DC3 uses MSVC mangling, RB3 uses MetroWerks (CW)
• Compiler: DC3 targets Xbox 360 (MSVC PPC), RB3 targets Wii (CW PPC/Gekko)
• Compiler flags: RB3 uses -O4,p -inline noauto -ipa file; DC3 uses MSVC /O2
• Class layouts: May differ slightly due to different compilers/alignment rules
• Includes: Header paths are generally the same for system/ code
• Assertions: Both use MILO_ASSERT but line numbers differ

Porting Workflow

1. Run /analyze-function on the RB3 symbol to see Ghidra + current state
2. Run /dc3-pair unit-name --source to see DC3's implementation
3. Adapt the DC3 source for RB3 (fix includes, member names, assertions)
4. Build with ninja and check match with objdiff

Tips

• DC3 decomp is ~87% complete -- excellent reference for shared engine code
• DC3 source: /home/free/code/milohax/dc3-decomp/src/system/
• Only system/ code overlaps significantly; band3/ and network/ are game-specific
• Use bin/analyze-function first to understand what the original RB3 code does
• Always verify with objdiff after porting -- identical C++ can compile differently under CW vs MSVC