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