Proper kernel

README.md

@@ -7,7 +7,8 @@ A minimal bootable UEFI operating system written in C that demonstrates basic UE
 - **UEFI Boot**: Boots directly on UEFI firmware
 - **Console I/O**: Interactive keyboard input and screen output
 - **System Information**: Displays firmware details
-- **Simple Commands**: Interactive command interface
+- **Kernel Loader**: Loads an ELF64 kernel from the EFI partition
+- **Simple Commands**: Minimal interactive command interface
 
 ## Requirements
 
@@ -44,13 +45,13 @@ sudo dnf install gnu-efi qemu-system-x86 edk2-ovmf gcc binutils make
 
 ## Building
 
-Build the UEFI application:
+Build the UEFI application and kernel:
 
 ```bash
 make
 ```
 
-This will create `build/EFI/BOOT/BOOTX64.EFI`
+This will create `build/EFI/BOOT/BOOTX64.EFI` and `build/kernel.elf`.
 
 ## Running
 
@@ -60,24 +61,43 @@ Test with QEMU (no graphics mode):
 make run
 ```
 
+The loader expects `kernel.elf` at the root of the EFI partition (next to the `EFI/` directory).
+
 ### QEMU Controls:
 - **Exit QEMU**: Press `Ctrl+A`, then `X`
-- **Shutdown OS**: Press `q` in the OS
+- **Shutdown OS**: Type `shutdown` in the OS
 
 ## Commands in the OS
 
 Once the OS boots, you can use these commands:
 
-- `h` - Display help
-- `i` - Display system information
-- `c` - Clear screen
-- `q` - Shutdown the system
+- `help` - Display all available commands
+- `man <command>` - Display detailed help for a command
+- `shutdown` - Shutdown the system
+- `clear` - Clear the screen
+- `about` - Display system information
+
+Example usage:
+```
+-> help
+-> man shutdown
+-> clear
+-> about
+-> shutdown
+```
 
 ## Project Structure
 
 ```
 .
-├── main.c          # Main UEFI application source code
+├── main.c          # UEFI loader (reads and loads kernel ELF)
+├── kernel.c        # Kernel entry point and main loop
+├── commands.c      # Command registry and handlers
+├── commands.h      # Command interface definitions
+├── string_utils.c  # String utility functions
+├── string_utils.h  # String utility declarations
+├── kernel.ld       # Kernel linker script
+├── boot_info.h     # Shared boot interface
 ├── Makefile        # Build configuration
 └── README.md       # This file
 ```
@@ -87,9 +107,17 @@ Once the OS boots, you can use these commands:
 1. **UEFI Entry Point**: The `efi_main` function is the entry point called by UEFI firmware
 2. **Initialization**: GNU-EFI library is initialized with the system table
 3. **Console Setup**: Output is configured and screen is cleared
-4. **Main Loop**: The OS enters a loop waiting for keyboard input
-5. **Command Processing**: User commands are processed and executed
-6. **Shutdown**: UEFI runtime services are used to shutdown the system
+4. **Kernel Load**: The loader reads `kernel.elf` and maps its loadable segments
+5. **Main Loop**: The kernel enters a loop waiting for keyboard input
+6. **Command Processing**: User commands are parsed and dispatched to registered handlers
+7. **Command Execution**: Each command is executed via its handler function
+8. **Shutdown**: UEFI runtime services are used to shutdown the system
+
+**Command System Architecture:**
+- Commands are registered in a static array with metadata (name, description, usage, handler)
+- The `execute_command()` function parses input, splits command and arguments, and dispatches to handlers
+- The `man` command provides detailed help by looking up command metadata
+- New commands can be easily added by implementing a handler and registering it
 
 ## Building for Real Hardware
 
@@ -99,7 +127,8 @@ To create a bootable USB drive:
 2. Format a USB drive with GPT and create an EFI partition (FAT32)
 3. Mount the EFI partition
 4. Copy `build/EFI/BOOT/BOOTX64.EFI` to `/EFI/BOOT/` on the USB drive
-5. Boot from the USB drive in UEFI mode
+5. Copy `build/kernel.elf` to the root of the EFI partition
+6. Boot from the USB drive in UEFI mode
 
 **Warning**: Always backup your data before creating bootable media!
 
@@ -146,11 +175,19 @@ This is a minimal educational example. Feel free to use and modify as needed.
 
 ## Further Development
 
-Ideas for expansion:
+The codebase is now modular and easy to extend:
+
+**Adding New Commands:**
+1. Open `commands.c`
+2. Create a new handler function: `static void cmd_yourcommand(BootInfo *Boot, CHAR16 *Args)`
+3. Add your command to the `commands[]` array with name, description, usage, and handler
+4. Rebuild with `make`
+
+**Other Ideas for expansion:**
 - File system support
 - Memory management
 - Graphics output
-- Network stack
+- Network stack  
 - Device drivers
 - Multi-tasking