A poorly written OS for the x86 arch. (WIP)
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eOS/src/bootloader.asm

50 lines
879 B

%include "equ/BIOS.asm"
%include "equ/ASCII.asm"
mov ah, BIOS_MODE_TELETYPE ; enter teletype mode (BIOS)
mov al, ASCII_LINEBREAK ; linebreak
int BIOS_INT
; Print "eOS"
mov al, "e"
int BIOS_INT
mov al, "O"
int BIOS_INT
mov al, "S"
int BIOS_INT
mov al, ASCII_CARRIAGE_RETURN
int BIOS_INT
mov al, ASCII_LINEBREAK ; linebreak
int BIOS_INT
; ALPHABET PRINT
mov al, 64 ; one less than A since we are printing in a loop and it increments before sys interupt
loop:
; Print the alphabetic char
inc al ; move to next char
int BIOS_INT ; bios interupt to print it
push ax ; push ax onto stack
; newline
mov al, ASCII_CARRIAGE_RETURN
int BIOS_INT
mov al, ASCII_LINEBREAK
int BIOS_INT
; Prepair for next iteration
pop ax ; restore
cmp al, 90 ; 26 letters in english alphabet (64 + 26)
jl loop ; if al < 64+26: jmp loop
jmp $
times 510-($-$$) db 0
db 0x55, 0xaa