Add boot.asm

boot.asm

@@ -0,0 +1,72 @@
+[bits 16]          ; Set to 16-bit mode
+[org 0x7C00]      ; BIOS loads the bootloader at this address
+
+start:
+    ; Clear screen
+    mov ax, 0x0003   ; Set video mode to 3 (80x25 color text)
+    int 0x10        ; BIOS interrupt to set video mode
+
+    ; Print welcome message
+    mov si, welcome_message
+    call print_string
+
+command_loop:
+    ; Print prompt
+    mov si, prompt_message
+    call print_string
+
+    ; Read user input
+    call read_input
+
+    ; Process command
+    cmp al, 'h'      ; Check for 'h' command (help)
+    je print_help
+    cmp al, 'q'      ; Check for 'q' command (quit)
+    je quit_terminal
+
+    ; Unknown command response
+    mov si, unknown_command_message
+    call print_string
+    jmp command_loop  ; Repeat the command loop
+
+print_help:
+    mov si, help_message
+    call print_string
+    jmp command_loop  ; Return to command loop
+
+quit_terminal:
+    mov si, goodbye_message
+    call print_string
+    jmp hang          ; Hang the system
+
+; Function to read a character from keyboard input
+read_input:
+    mov ah, 0x00      ; BIOS function to read a character
+    int 0x16          ; Call BIOS interrupt
+    ret                ; Return with character in AL
+
+; Function to print a string
+print_string:
+    mov ah, 0x0E      ; BIOS teletype output function
+.next_char:
+    lodsb             ; Load byte at DS:SI into AL and increment SI
+    cmp al, 0         ; Check for null terminator
+    je .done          ; If null, we are done
+    int 0x10         ; Call BIOS to print character in AL
+    jmp .next_char   ; Repeat for next character
+.done:
+    ret               ; Return from function
+
+; Data section for messages
+welcome_message db 'Welcome to the Simple Terminal!', 0 
+prompt_message db 'Enter command (h for help, q to quit): ', 0 
+help_message db 'Available commands: h (help), q (quit)', 0 
+unknown_command_message db 'Unknown command! Try again.', 0 
+goodbye_message db 'Goodbye!', 0 
+
+; Bootloader signature (must be present)
+times 510 - ($ - $$) db 0   ; Fill the rest of the sector with zeros
+dw 0xAA55                   ; Boot signature
+
+hang:
+    jmp hang           ; Jump to hang indefinitely