## 1. AsmBuilder — Core (TDD: tests first)

- [ ] 1.1 Create `BlackMagicTest/AsmBuilderTests.cs` with tests for single-instruction assembly: `nop` → `[0x90]`, `pushad` → `[0x60]`, `popad` → `[0x61]`, `ret` → `[0xC3]`, `hlt` → `[0xF4]`
- [ ] 1.2 Create `BlackMagic/Asm/AsmBuilder.cs` with `Assemble(string source)` entry point and instruction table. Implement `nop`, `pushad`, `popad`, `ret`, `hlt` to make step 1.1 tests pass
- [ ] 1.3 Add tests for `mov reg, imm32` (eax, ecx, edx, ebx, esp, ebp, esi, edi) — each register maps to `0xB8 + reg` encoding with 4-byte little-endian immediate
- [ ] 1.4 Implement `mov reg, imm32` in AsmBuilder to make step 1.3 tests pass
- [ ] 1.5 Add tests for `mov reg, reg` (register-to-register via ModRM byte 0xC0 + (src<<3 | dst))
- [ ] 1.6 Implement `mov reg, reg` to make step 1.5 tests pass
- [ ] 1.7 Add tests for `push reg` (`0x50 + reg`), `pop reg` (`0x58 + reg`)
- [ ] 1.8 Implement `push reg`, `pop reg` to make step 1.7 tests pass
- [ ] 1.9 Add tests for `add reg, imm8` (`0x83 /0` with sign-extended byte), `sub reg, imm8` (`0x83 /5`), `xor reg, reg` (`0x31 /r`), `and reg, imm8`, `or reg, imm8`, `cmp reg, imm8` (`0x83 /7`)
- [ ] 1.10 Implement `add`, `sub`, `xor`, `and`, `or`, `cmp` to make step 1.9 tests pass
- [ ] 1.11 Add tests for `inc reg` (`0x40 + reg`), `dec reg` (`0x48 + reg`), `test reg, reg` (`0x85 /r`)
- [ ] 1.12 Implement `inc`, `dec`, `test` to make step 1.11 tests pass
- [ ] 1.13 Add tests for `jmp @label`, `je @label`, `jne @label` with forward and backward references
- [ ] 1.14 Implement two-pass label resolution in AsmBuilder (pass 1: record label offsets, pass 2: patch jump targets). Make step 1.13 tests pass
- [ ] 1.15 Add tests for `call @label` (near call, E8 rel32) and `nop` multi-instruction sequences
- [ ] 1.16 Implement `call` to make step 1.15 tests pass
- [ ] 1.17 Add tests for error cases: unknown instruction → `ArgumentException` with line number, missing operand → `ArgumentException`, invalid register → `ArgumentException`
- [ ] 1.18 Implement error reporting to make step 1.17 tests pass

## 2. AsmBuilder — Pass Limit

- [ ] 2.1 Add tests for `SetPassLimit()`: default is 10, custom value is respected, exceeded limit throws `InvalidOperationException`
- [ ] 2.2 Implement `SetPassLimit(int limit)` and pass-limit enforcement in AsmBuilder to make step 2.1 tests pass

## 3. InjectAndExecuteEx — Non-blocking Execution

- [ ] 3.1 Add tests for `BlackMagic.InjectAndExecuteEx(IntPtr, IntPtr)`: returns `null` when no process open, returns valid handle when process open (mock or integration)
- [ ] 3.2 Implement `InjectAndExecuteEx(IntPtr startAddress, IntPtr parameter)` in `BMThread.cs` to make step 3.1 tests pass
- [ ] 3.3 Add test for single-parameter overload: `InjectAndExecuteEx(IntPtr)` passes `IntPtr.Zero`
- [ ] 3.4 Implement `InjectAndExecuteEx(IntPtr startAddress)` overload in `BMThread.cs`

## 4. Convenience Overloads (text → inject → execute)

- [ ] 4.1 Add tests for `InjectAndExecute(string asm)`: assembles text, allocates remote memory, writes bytes, executes, returns exit code. Test assembly failure → `ArgumentException`
- [ ] 4.2 Implement `InjectAndExecute(string asm)` in `BMInject.cs` to make step 4.1 tests pass
- [ ] 4.3 Add tests for `InjectAndExecuteEx(string asm)`: assembles text, allocates remote memory, writes bytes, returns thread handle. Test assembly failure → `ArgumentException`
- [ ] 4.4 Implement `InjectAndExecuteEx(string asm)` in `BMInject.cs` to make step 4.3 tests pass

## 5. Build Verification

- [ ] 5.1 Run full test suite: `"C:\Program Files\dotnet\dotnet.exe" test BlackMagicTest/BlackMagicTest.csproj` — all tests pass
- [ ] 5.2 Run full solution build: `"C:\Program Files\dotnet\dotnet.exe" build BlackMagic.slnx` — zero errors