Компиляция загрузчика IO.SYS, для uefi

format binary as 'uefi_bios_bootloader_io.sys'
 
org 0x7c00
 
start:
    ; Set up stack
    xor ax, ax
    mov ss, ax
    mov sp, 0x7c00
 
    ; Set up data segments
    mov ax, 0x07c0
    mov ds, ax
    mov es, ax
 
    ; Clear screen
    mov ah, 0x06       ; Scroll screen function
    xor al, al         ; Number of lines to scroll
    mov bh, 0x00       ; Attribute
    mov cx, 0x0000     ; Upper-left corner
    mov dx, 0x184f     ; Lower-right corner
    int 0x10
 
    ; Print message
    mov si, message
    call print_string
 
    ; Load and execute io.sys
    mov ax, 0x0201     ; Load and execute function
    mov cx, 0x0002     ; Number of sectors to read
    mov dx, 0x0000     ; Destination segment (0x0000:0x7e00)
    mov bx, 0x7e00     ; Destination offset
    mov es, dx         ; Set ES to destination segment
    mov dl, 0x80       ; Drive number (assuming boot drive is 0x80)
    mov dh, 0x00       ; Head
    mov ch, 0x00       ; Cylinder
    mov cl, 0x02       ; Sector
    mov ah, 0x02       ; Read sectors function
    int 0x13           ; BIOS interrupt
 
    ; Jump to loaded program
    mov ax, 0x7e00
    mov ds, ax
    mov es, ax
    jmp 0x0000:0x7e00
 
print_string:
    lodsb              ; Load next byte from SI into AL
    test al, al        ; Check if AL is zero (end of string)
    jz .done           ; If zero, jump to end
    mov ah, 0x0e       ; Teletype output function
    mov bh, 0x00       ; Video page number
    mov bl, 0x07       ; Text attribute
    int 0x10           ; Call BIOS interrupt
    jmp print_string   ; Continue printing
.done:
    ret
 
message db 'UEFI Bootloader', 0
 
times 510-($-$$) db 0
dw 0xaa55

format PE64 EFI
entry here
here: ret