Many things

Renamed main.asm in boot.asm and moved it into the bootloader directory, created an empty kernel.asm file, edited Makefile and edited the bootloader (boot.asm).

Makefile

@@ -3,9 +3,43 @@ ASM=nasm
 SRC_DIR=src
 BUILD_DIR=build
 
-$(BUILD_DIR)/main_floppy.img: $(BUILD_DIR)/main.bin
-	cp $(BUILD_DIR)/main.bin $(BUILD_DIR)/main_floppy.img
-	truncate -s 1440k $(BUILD_DIR)/main_floppy.img
+.PHONY: all floppy_image kernel bootloader clean always
 
-$(BUILD_DIR)/main.bin: $(SRC_DIR)/main.asm
-	$(ASM) $(SRC_DIR)/main.asm -f bin -o $(BUILD_DIR)/main.bin
+
+#Immagine floppy
+
+immagine_floppy: $(BUILD_DIR)/main_floppy.img
+
+$(BUILD_DIR)/main_floppy.img: bootloader kernel
+	dd if=/dev/zero of=$(BUILD_DIR)/main_floppy.img bs=512 count=2880
+	mkfs.fat -F 12 -n "XanvOS" $(BUILD_DIR)/main_floppy.img
+	dd if=$(BUILD_DIR)/bootloader.bin of=$(BUILD_DIR)/main_floppy.img conv=notrunc
+	mcopy -i $(BUILD_DIR)/main_floppy.img $(BUILD_DIR)/kernel.bin "::kernel.bin"
+
+
+#Kernel
+
+kernel: $(BUILD_DIR)/kernel.bin
+
+$(BUILD_DIR)/kernel.bin: always
+	$(ASM) $(SRC_DIR)/kernel/kernel.asm -f bin -o $(BUILD_DIR)/kernel.bin
+
+
+#Bootloader
+
+bootloader: $(BUILD_DIR)/bootloader.bin
+
+$(BUILD_DIR)/bootloader.bin: always
+	$(ASM) $(SRC_DIR)/bootloader/boot.asm -f bin -o $(BUILD_DIR)/bootloader.bin
+
+
+#Always
+
+always:
+	mkdir -p $(BUILD_DIR)
+
+
+#Clean
+
+clean:
+	rm -rf $(BUILD_DIR)/* 

src/bootloader/boot.asm

@@ -0,0 +1,182 @@
+org 0x7C00
+bits 16
+
+%define ENDL 0x0D, 0x0A
+
+;Headers di FAT12 (senza questa parte si sminchia il FAT12 e non si crea l'immagine floppy)
+
+jmp short start
+nop
+
+bdb_oem:					db 'MSWIN4.1'
+bdb_bytes_per_sector:		dw 512
+bdb_sectors_per_cluster:	db 1
+bdb_reserved_sectors:		dw 1
+bdb_fat_count:				db 2
+bdb_dir_entries_count:		dw 0E0h
+bdb_total_sectors:			dw 2880
+bdb_media_descriptor_type:	db 0F0h
+bdb_sectors_per_fat:		dw 9
+bdb_sectors_per_track:		dw 18
+bdb_heads:					dw 2
+bdb_hidden_sectors:			dd 0
+bdb_large_sector_count:		dd 0
+
+ebr_drive_number:			db 0
+							db 0
+ebr_signature:				db 29h
+ebr_volume_id:				db 12h, 34h, 56h, 78h	
+ebr_volume_label:			db 'XanvicOS   '
+ebr_system_id:				db 'FAT12   '
+
+;Codice
+
+start:
+	jmp main
+
+puts:
+	push si
+	push ax
+	push bx
+	
+.loop:
+	lodsb 
+	or al, al
+	jz .fine
+
+	mov ah, 0x0E
+	mov bh, 0
+	int 0x10
+	
+	jmp .loop
+	
+.fine:
+	pop bx
+	pop ax
+	pop si
+	ret
+
+main:
+	mov ax, 0
+	mov ds, ax
+	mov es, ax
+
+	mov ss, ax
+	mov sp, 0x7C00
+
+	mov si, msg_helloworld
+	call puts
+
+	;Legge cose dal floppy
+	mov [ebr_drive_number], dl
+
+	mov ax, 1
+	mov cl, 1
+	mov bx, 0x7E00
+	call lettura_disco
+
+	cli
+	hlt
+
+;Errori
+
+errore_floppy:
+	mov si, msg_errore_lettura
+	call puts
+	jmp premi_per_riavviare
+
+premi_per_riavviare:
+	mov ah, 0
+	int 16h
+	jmp 0FFFFh:0 
+
+.halt:
+	cli
+	hlt
+
+;Trasforma/Converte un indirizzo LBA in uno CHS
+
+lba_to_chs:
+	push ax
+	push dx
+	
+	xor dx, dx
+	div word [bdb_sectors_per_track]
+	
+	inc dx
+	mov cx, dx
+
+	xor dx, dx
+	div word [bdb_heads]
+
+	mov dh, dl
+	mov ch, al
+	shl ah, 6
+	or cl, ah
+
+	pop ax
+	mov dl, al
+	pop ax
+
+	ret
+
+;Legge i settori da un disco
+
+lettura_disco:
+;	push ax
+;	push bx
+	push cx
+;	push dx
+;	push di
+
+	call lba_to_chs
+	pop ax
+
+	mov ah, 02h
+	mov di, 3
+
+.riprova:
+	pusha
+	stc
+	int 13h
+	jnc .fine
+
+	;Errore nella lettura del disco
+	popa
+	call disk_reset
+
+	dec di
+	test di, di
+	jnz .riprova
+
+.errore:
+	jmp errore_floppy
+
+.fine:
+	popa
+
+;	pop di
+;	pop dx
+;	pop cx
+;	pop bx
+;	pop ax
+	ret
+
+disk_reset:
+	pusha
+	mov ah, 0
+	stc
+	int 13h
+	jc errore_floppy
+	popa
+	ret
+
+;Mostra una stringa sullo schermo
+
+msg_helloworld: 
+	db 'Hello World!', ENDL, 0
+msg_errore_lettura:
+	db 'Errore nella lettura del disco!'
+
+times 510-($-$$) db 0
+dw 0AA55h

src/main.asm

@@ -1,51 +0,0 @@
-org 0x7C00
-bits 16
-
-%define ENDL 0x0D, 0x0A
-
-start:
-	jmp main
-
-puts:
-	push si
-	push ax
-	push bx
-	
-.loop:
-	lodsb 
-	or al, al
-	jz .done
-
-	mov ah, 0x0E
-	mov bh, 0
-	int 0x10
-	
-	jmp .loop
-	
-.done:
-	pop bx
-	pop ax
-	pop si
-	ret
-
-main:
-
-	mov ax, 0
-	mov ds, ax
-	mov es, ax
-
-	mov ss, ax
-	mov sp, 0x7C00
-
-	mov si, msg_hello
-	call puts
-
-	hlt
-
-.halt:
-	jmp .halt
-
-msg_hello: db 'Hello World!', ENDL, 0
-
-times 510-($-$$) db 0
-dw 0AA55h