Grow-with-Open-Source · ghost · Nov 10, 2024
diff --git a/EDI-OS/EDI-OS.png b/EDI-OS/EDI-OS.png
diff --git a/EDI-OS/README.md b/EDI-OS/README.md
@@ -0,0 +1,84 @@
+# EDI-OS
+
+EDI-OS is an operating system simplified for educational purposes. This OS covers the minimum requirements of an OS but keeps the source code understandable and easy to comprehend.
+
+![EDI-OS Boot Screen](./EDI-OS.png)
+
+## Features
+
+• Custom bootloader
+• 32-bit protected mode kernel
+• VGA text mode display (80x25)
+• Basic keyboard input handling
+• Command-line interface
+• Color-coded debug/status messages
+• Memory management initialization
+• PS/2 keyboard controller support
+• Basic command set: help, clear, version, about
+
+### Dependencies
+
+• NASM: Netwide Assembler
+• GCC with support for 32-bit target
+- LD (GNU Linkер)
+- QEMU (for emulation)
+- Make
+
+For Debian/Ubuntu-based systems:
+```bash
+sudo apt-get install nasm gcc gcc-multilib qemu-system-x86 make
+```
+
+### Running
+
+For running in QEMU :
+```bash
+make run
+```
+
+For debug mode with QEMU monitor:
+```bash
+make debug
+```
+
+## Project Structure
+
+- `boot.asm` - Bootloader with detailed messages
+- `kernel.c` - Main kernel with terminal and routines
+- `keyboard.c` - Keyboard handling and command processing
+- `kernel.h` - Kernel header with type definitions and function declarations
+- `linker.ld` - Linker script for kernel building
+- `Makefile` - Build automation
+
+## Boot Sequence
+
+1. Initialization of bootloader
+2. Check memory
+3. Initialization of disk system
+4. Loading kernel
+5. Switch to protected mode
+6. Initialization of kernel
+   - Setup video
+   - Memory management
+   - Setup keyboard controller
+   - Setup interrupt handlers
+
+## Available Commands
+
+- `help` - View list of available commands
+- `clear` - Clear screen
+- `version` - View OS version
+- `about` - View information about EDI-OS
+
+## Technical Details
+
+Boots from a virtual floppy disk (1.44MB)
+Loads at the 1MB mark
+Uses a custom GDT setup
+imple I/O port handling
+VGA text mode with color support
+PS/2 keyboard support with scancode mapping
+
+## Contributing
+
+Contributions are welcome! Feel free to send a Pull Request.
diff --git a/EDI-OS/src/Makefile b/EDI-OS/src/Makefile
@@ -0,0 +1,59 @@
+# Compiler and flags
+CC = gcc
+AS = nasm
+LD = ld
+
+CFLAGS = -m32 -fno-pie -ffreestanding -fno-builtin -O2 -Wall -Wextra -fno-stack-protector -nostdlib -nodefaultlibs
+ASFLAGS = -f elf32
+LDFLAGS = -m elf_i386 -T linker.ld --oformat binary
+
+# Source files
+BOOT_SRC = boot.asm
+KERNEL_ENTRY_SRC = kernel_entry.asm
+KERNEL_SRC = kernel.c
+KEYBOARD_SRC = keyboard.c
+
+# Object files
+BOOT_BIN = boot.bin
+KERNEL_ENTRY_OBJ = kernel_entry.o
+KERNEL_OBJ = kernel.o
+KEYBOARD_OBJ = keyboard.o
+KERNEL_BIN = kernel.bin
+OS_IMAGE = os-image.bin
+
+# Build rules
+all: $(OS_IMAGE)
+
+$(BOOT_BIN): $(BOOT_SRC)
+	$(AS) -f bin -o $@ $<
+
+$(KERNEL_ENTRY_OBJ): $(KERNEL_ENTRY_SRC)
+	$(AS) $(ASFLAGS) -o $@ $<
+
+$(KERNEL_OBJ): $(KERNEL_SRC)
+	$(CC) $(CFLAGS) -c $< -o $@
+
+$(KEYBOARD_OBJ): $(KEYBOARD_SRC)
+	$(CC) $(CFLAGS) -c $< -o $@
+
+$(KERNEL_BIN): $(KERNEL_ENTRY_OBJ) $(KERNEL_OBJ) $(KEYBOARD_OBJ)
+	$(LD) $(LDFLAGS) -o $@ $^
+
+$(OS_IMAGE): $(BOOT_BIN) $(KERNEL_BIN)
+	# Create a blank 1.44MB floppy image
+	dd if=/dev/zero of=$@ bs=1024 count=1440
+	# Write boot sector to first sector
+	dd if=$(BOOT_BIN) of=$@ conv=notrunc
+	# Write kernel starting at second sector
+	dd if=$(KERNEL_BIN) of=$@ seek=1 conv=notrunc
+
+run: $(OS_IMAGE)
+	qemu-system-i386 -fda $(OS_IMAGE)
+
+debug: $(OS_IMAGE)
+	qemu-system-i386 -fda $(OS_IMAGE) -monitor stdio
+
+clean:
+	rm -f *.bin *.o
+
+.PHONY: all clean run debug
diff --git a/EDI-OS/src/boot.asm b/EDI-OS/src/boot.asm
@@ -0,0 +1,184 @@
+[org 0x7c00]
+[bits 16]
+
+; Constants
+KERNEL_OFFSET equ 0x1000
+VIDEO_MODE equ 0x03        ; 80x25 text mode
+STACK_BASE equ 0x9000
+SECTORS_TO_READ equ 15     ; Number of sectors for kernel
+
+; Initialize segments and stack
+xor ax, ax
+mov ds, ax
+mov es, ax
+mov ss, ax
+mov sp, STACK_BASE
+
+; Save boot drive number
+mov [BOOT_DRIVE], dl
+
+; Set video mode
+mov ah, 0x00
+mov al, VIDEO_MODE
+int 0x10
+
+; Print initial boot message
+mov si, MSG_BOOT
+call print_string
+mov cx, 5              ; Number of delay iterations
+call long_delay
+
+; Print memory check message
+mov si, MSG_MEM_CHECK
+call print_string
+mov cx, 4
+call long_delay
+
+; Reset disk system and show message
+mov si, MSG_DISK_RESET
+call print_string
+xor ah, ah
+mov dl, [BOOT_DRIVE]
+int 0x13
+jc disk_error
+mov cx, 4
+call long_delay
+
+; Load kernel message
+mov si, MSG_LOAD_KERNEL
+call print_string
+
+; Load kernel
+mov bx, KERNEL_OFFSET    ; Destination address
+mov dh, SECTORS_TO_READ  ; Sectors to read
+call load_disk
+mov cx, 4
+call long_delay
+
+; Switch to protected mode message
+mov si, MSG_PROT_MODE
+call print_string
+mov cx, 4
+call long_delay
+
+; Switch to protected mode
+cli                      ; Clear interrupts
+lgdt [GDT_DESCRIPTOR]    ; Load GDT
+mov eax, cr0
+or eax, 0x1             ; Set protected mode bit
+mov cr0, eax
+jmp CODE_SEG:init_pm    ; Far jump to 32-bit code
+
+; Function to add a longer delay
+; cx = number of iterations
+long_delay:
+    push cx             ; Save outer loop counter
+.outer_loop:
+    push cx
+    mov cx, 0xFFFF      ; Maximum 16-bit value
+.inner_loop1:
+    push cx
+    mov cx, 0x0FFF      ; Increased inner delay
+.inner_loop2:
+    loop .inner_loop2
+    pop cx
+    loop .inner_loop1
+    pop cx
+    loop .outer_loop
+    pop cx              ; Restore outer loop counter
+    ret
+
+load_disk:
+    push dx             ; Save DX
+
+    mov ah, 0x02       ; BIOS read function
+    mov al, dh         ; Number of sectors
+    mov ch, 0          ; Cylinder 0
+    mov dh, 0          ; Head 0
+    mov cl, 2          ; Start from sector 2
+    mov dl, [BOOT_DRIVE]
+
+    int 0x13
+    jc disk_error      ; Check for error
+
+    pop dx             ; Restore DX
+    cmp dh, al         ; Compare sectors read
+    jne disk_error     ; Error if not equal
+
+    ; Print success message
+    mov si, MSG_LOAD_OK
+    call print_string
+    ret
+
+disk_error:
+    mov si, DISK_ERROR_MSG
+    call print_string
+    jmp $
+
+print_string:
+    mov ah, 0x0E       ; BIOS teletype function
+.loop:
+    lodsb              ; Load next character
+    test al, al        ; Check for null terminator
+    jz .done           ; If zero, we're done
+    int 0x10          ; Otherwise, print
+    jmp .loop
+.done:
+    ret
+
+[bits 32]
+init_pm:
+    mov ax, DATA_SEG
+    mov ds, ax
+    mov ss, ax
+    mov es, ax
+    mov fs, ax
+    mov gs, ax
+
+    mov ebp, STACK_BASE
+    mov esp, ebp
+
+    jmp KERNEL_OFFSET
+
+; Data
+BOOT_DRIVE db 0
+MSG_BOOT db 'EDI-OS Bootloader starting...', 0x0D, 0x0A, 0
+MSG_MEM_CHECK db 'Checking memory map...OK', 0x0D, 0x0A, 0
+MSG_DISK_RESET db 'Resetting disk system...', 0x0D, 0x0A, 0
+MSG_LOAD_KERNEL db 'Loading kernel into memory...', 0x0D, 0x0A, 0
+MSG_LOAD_OK db 'Kernel loaded successfully!', 0x0D, 0x0A, 0
+MSG_PROT_MODE db 'Switching to protected mode...', 0x0D, 0x0A, 0
+DISK_ERROR_MSG db 'Disk read error!', 0x0D, 0x0A, 0
+
+; GDT
+GDT_START:
+    dq 0               ; Null descriptor
+
+GDT_CODE:
+    dw 0xFFFF          ; Limit (0-15)
+    dw 0               ; Base (0-15)
+    db 0               ; Base (16-23)
+    db 10011010b       ; Access byte
+    db 11001111b       ; Flags and limit (16-19)
+    db 0               ; Base (24-31)
+
+GDT_DATA:
+    dw 0xFFFF
+    dw 0
+    db 0
+    db 10010010b
+    db 11001111b
+    db 0
+
+GDT_END:
+
+GDT_DESCRIPTOR:
+    dw GDT_END - GDT_START - 1
+    dd GDT_START
+
+CODE_SEG equ GDT_CODE - GDT_START
+DATA_SEG equ GDT_DATA - GDT_START
+
+; Boot signature
+times 510-($-$$) db 0
+dw 0xAA55