Development

[assembler-0]

Summary by CodeRabbit

• New Features
  • Added a 6502 CPU emulator reachable via the shell "6502" command; runs a built-in demo and prints a concise post-run summary of registers, flags, memory, and PC for quick testing and learning.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

Adds C linkage guards to Console public declarations, registers a new Shell command "6502", integrates C++ compilation into the kernel build, and introduces a C++ 6502 emulator with an extern "C" Entry6502 entry point and its header.

Changes

Cohort / File(s)	Summary
Console C linkage kernel/etc/Console.h	Wraps public Console function prototypes in an extern "C" block guarded by #ifdef __cplusplus; no signature changes.
Shell command registration kernel/etc/Shell.c	Adjusts includes to add ports/6502/6502.h (keeps NIC include); adds shell command entry { "6502", Entry6502 } to the commands table.
Build system: C++ enablement meson.build	Adds clang++ lookup, C++ flags (-std=gnu++17, -fno-exceptions, -fno-rtti, etc.), include dirs for ports/6502 and ports, compiles ports/6502/6502.cpp to objects and links them into the kernel.
6502 emulator (new) ports/6502/6502.cpp, ports/6502/6502.h	New C++ 6502 emulator implementation (MEM/CPU, addressing modes, opcode set, execute loop) exposing extern "C" void Entry6502(const char * args); header declares void Entry6502(const char * args);.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  actor User
  participant Shell as Shell (kernel/etc/Shell.c)
  participant Entry as Entry6502 (ports/6502/6502.cpp)
  participant CPU as 6502 CPU/MEM
  participant Console as Console API

  User->>Shell: types "6502"
  Shell->>Entry: Entry6502(args)
  rect rgb(235,245,255)
    note right of Entry: initialize MEM & CPU, set reset vector, load test program
    Entry->>CPU: Init()/Reset()
    Entry->>CPU: Load program @0xF000
  end
  loop run cycles / until BRK
    Entry->>CPU: Fetch/Decode/Execute (step)
    alt page-cross or branch taken
      CPU-->>CPU: adjust cycles/PC
    else normal
      CPU-->>CPU: update regs/flags/memory
    end
  end
  Entry->>Console: print registers/flags/memory (via Console API)
  Console-->>User: output

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Estimated code review effort

🎯 4 (Complex) | ⏱️ ~60 minutes

Possibly related PRs

• Development #117 — Appears to include the same changes (Console C linkage, ports/6502 sources, meson.build updates); likely directly related.
• THE vbe is cooked #62 — Modifies Console API declarations/console features; strongly related to the Console.h linkage changes.

Poem

I nibble opcodes by moonlit code,
A tiny CPU upon my road.
Shell beckons, Entry opens the gate,
Cycles hum and flags update.
Hoppity hop — the emulator’s awake! 🐇✨

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 7ce19a3 and 29b520a.

📒 Files selected for processing (3)

• meson.build (5 hunks)
• ports/6502/6502.cpp (1 hunks)
• ports/6502/6502.h (1 hunks)

✨ Finishing Touches

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🧪 Generate unit tests

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch Development

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[coderabbitai]

Actionable comments posted: 6

🧹 Nitpick comments (1)

kernel/etc/Shell.c (1)

1173-1174: Add help entry for the new “6502” command

So users discover it via ‘help’. Consider adding a short description under Development commands.

 static const HelpEntry dev_cmds[] = {
     {"elfload <path>", "Load ELF executable"},
     {"alloc <size>", "Allocate memory"},
     {"panic <msg>", "Trigger panic"},
     {"vmemfreelist", "Show VMem free list"},
     {"heapvallvl <0/1/2>", "Set heap validation level"},
     {"fstest", "Run filesystem tests"},
     {"arptest", "Perform ARP test"},
     {"setup", "Copy system files"},
-    {"isocp <iso> <vfs>", "Copy from ISO to VFS"}
+    {"isocp <iso> <vfs>", "Copy from ISO to VFS"},
+    {"6502", "Run the 6502 emulator demo"}
 };

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between f32ee9c and 7ce19a3.

📒 Files selected for processing (5)

• kernel/etc/Console.h (2 hunks)
• kernel/etc/Shell.c (2 hunks)
• meson.build (4 hunks)
• ports/6502/6502.cpp (1 hunks)
• ports/6502/6502.h (1 hunks)

🧰 Additional context used

🧬 Code graph analysis (3)

ports/6502/6502.h (1)

ports/6502/6502.cpp (2)

• Entry6502 (363-406)
• Entry6502 (363-363)

ports/6502/6502.cpp (1)

kernel/etc/Console.c (2)

• PrintKernelF (260-267)
• PrintKernel (181-199)

kernel/etc/Shell.c (1)

ports/6502/6502.cpp (2)

• Entry6502 (363-406)
• Entry6502 (363-363)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)

• GitHub Check: build

🔇 Additional comments (2)

kernel/etc/Shell.c (1)

2-3: Includes look good

6502 header inclusion is correct given the new inc_dirs; no issues spotted.

ports/6502/6502.cpp (1)

208-219: Overflow flag computation is fine; keep it boolean

Assignment to a 1-bit field from 0x80 coerces to 0/1; this is intentional and correct. Just a note that the semantics are clear.