Add bootloader's 2nd stage written in C and asm

Now the bootloader is divided in stage1 and stage 2, the kernel isn't loaded so it's useless (for now).
The Stage 1 of the bootloader prints some strings and loads the second stage into memory. The second stage prints a hello world message.
After this commit I'll divide the main branch into stable and coding (stable is working code, like all the commits I did until this day, coding will be the branch where I push all the code I write, so there may be a lot of errors or the code doesn't compile. I you want to use or just try XanvicOS use the stable branch)

Makefile

@@ -1,9 +1,12 @@
 ASM=nasm
+CC=gcc
+CC16=/usr/bin/watcom/binl/wcc
+LD16=/usr/bin/watcom/binl/wlink
 
 SRC_DIR=src
 BUILD_DIR=build
 
-.PHONY: all floppy_image kernel bootloader clean always
+.PHONY: all immagine_floppy kernel bootloader clean always
 
 
 #Immagine floppy
@@ -13,8 +16,10 @@ 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=$(BUILD_DIR)/main_floppy.img conv=notrunc
+	dd if=$(BUILD_DIR)/stage1.bin of=$(BUILD_DIR)/main_floppy.img conv=notrunc
+	mcopy -i $(BUILD_DIR)/main_floppy.img $(BUILD_DIR)/stage2.bin "::stage2.bin"
 	mcopy -i $(BUILD_DIR)/main_floppy.img $(BUILD_DIR)/kernel.bin "::kernel.bin"
+	mcopy -i $(BUILD_DIR)/main_floppy.img test.txt "::test.txt"
 
 
 #Kernel
@@ -22,15 +27,23 @@ $(BUILD_DIR)/main_floppy.img: bootloader kernel
 kernel: $(BUILD_DIR)/kernel.bin
 
 $(BUILD_DIR)/kernel.bin: always
-	$(ASM) $(SRC_DIR)/kernel/kernel.asm -f bin -o $(BUILD_DIR)/kernel.bin
+	$(MAKE) -C $(SRC_DIR)/kernel  BUILD_DIR=$(abspath $(BUILD_DIR))
 
 
 #Bootloader
 
-bootloader: $(BUILD_DIR)/bootloader.bin
+bootloader: stage1 stage2
 
-$(BUILD_DIR)/bootloader.bin: always
+stage1: $(BUILD_DIR)/stage1.bin
-	$(ASM) $(SRC_DIR)/bootloader/boot.asm -f bin -o $(BUILD_DIR)/bootloader.bin
+
+$(BUILD_DIR)/stage1.bin: always
+	$(MAKE) -C $(SRC_DIR)/bootloader/stage1  BUILD_DIR=$(abspath $(BUILD_DIR))
+
+
+stage2: $(BUILD_DIR)/stage2.bin
+
+$(BUILD_DIR)/stage2.bin: always
+	$(MAKE) -C $(SRC_DIR)/bootloader/stage2  BUILD_DIR=$(abspath $(BUILD_DIR))
 
 
 #Always

src/bootloader/stage1/Makefile

@@ -0,0 +1,15 @@
+BUILD_DIR?=build/
+ASM?=nasm
+
+
+.PHONY: all clean
+
+all: stage1
+
+stage1: $(BUILD_DIR)/stage1.bin
+
+$(BUILD_DIR)/stage1.bin:
+	$(ASM) stage1.asm -f bin -o $(BUILD_DIR)/stage1.bin
+
+clean:
+	rm -f $(BUILD_DIR)/stage1.bin

src/bootloader/stage1/stage1.asm

@@ -101,28 +101,28 @@ start:
 	xor bx, bx
 	mov di, buffer
 
-.cerca_kernel:
+.cerca_stage2:
-	mov si, file_kernel_bin
+	mov si, file_stage2_bin
 	mov cx, 11
 	push di
 	repe cmpsb
 	pop di
-	je .kernel_trovato
+	je .stage2_trovato
 
 	add di, 32
 	inc bx
 	cmp bx, [dir_entries_count]
-	jl .cerca_kernel
+	jl .cerca_stage2
 
 	;Kernel non trovato
-	jmp errore_kernel_non_trovato
+	jmp errore_stage2_non_trovato
 
-.kernel_trovato:
+.stage2_trovato:
-	mov si, msg_kernel_trovato
+	mov si, msg_stage2_trovato
 	call puts
 
 	mov ax, [di + 26]
-	mov [kernel_cluster], ax
+	mov [stage2_cluster], ax
 
 	mov ax, [reserved_sectors]
 	mov bx, buffer 
@@ -130,12 +130,12 @@ start:
 	mov dl, [ebr_drive_number]
 	call lettura_disco
 
-	mov bx, KERNEL_LOAD_SEGMENT
+	mov bx, STAGE2_LOAD_SEGMENT
 	mov es, bx
-	mov bx, KERNEL_LOAD_OFFSET
+	mov bx, STAGE2_LOAD_OFFSET
 
-.carica_kernel:
+.carica_stage2:
-	mov ax, [kernel_cluster]
+	mov ax, [stage2_cluster]
 	add ax, 31
 
 	mov cl, 1
@@ -144,7 +144,7 @@ start:
 
 	add bx, [bytes_per_sector]
 
-	mov ax, [kernel_cluster]
+	mov ax, [stage2_cluster]
 	mov cx, 3
 	mul cx
 	mov cx, 2
@@ -168,18 +168,17 @@ start:
 	cmp ax, 0x0FF8
 	jae .fine_lettura
 
-	mov [kernel_cluster], ax
+	mov [stage2_cluster], ax
-	jmp .carica_kernel
+	jmp .carica_stage2
 
 .fine_lettura:
 	mov dl, [ebr_drive_number]
 	
-	mov ax, KERNEL_LOAD_SEGMENT
+	mov ax, STAGE2_LOAD_SEGMENT
 	mov ds, ax
 	mov es, ax
 
-	jmp KERNEL_LOAD_SEGMENT:KERNEL_LOAD_OFFSET
+	jmp STAGE2_LOAD_SEGMENT:STAGE2_LOAD_OFFSET
-	jmp premi_per_riavviare
 
 ;Trasforma/Converte un indirizzo LBA in uno CHS
 
@@ -280,11 +279,11 @@ msg_caricamento:
 msg_errore_lettura:
 	db 'Errore del disco', ENDL, 0
 
-msg_kernel_non_trovato:
+msg_stage2_non_trovato:
-	db 'Kernel non trovato', ENDL, 0
+	db 'Stage 2 non trovato', ENDL, 0
 
-msg_kernel_trovato:
+msg_stage2_trovato:
-	db 'Kernel trovato', ENDL, 0
+	db 'Stage 2 trovato', ENDL, 0
 
 ;Errori
 
@@ -293,17 +292,17 @@ errore_floppy:
 	call puts
 	jmp premi_per_riavviare
 
-errore_kernel_non_trovato:
+errore_stage2_non_trovato:
-	mov si, msg_kernel_non_trovato
+	mov si, msg_stage2_non_trovato
 	call puts
 	jmp premi_per_riavviare
 
 ;Variabili
 
-file_kernel_bin:				db 'KERNEL  BIN'
+file_stage2_bin:				db 'STAGE2  BIN'
-kernel_cluster:					dw 0
+stage2_cluster:					dw 0
-KERNEL_LOAD_SEGMENT 			equ 0x2000
+STAGE2_LOAD_SEGMENT 			equ 0x2000
-KERNEL_LOAD_OFFSET				equ 0
+STAGE2_LOAD_OFFSET				equ 0
 
 ;Cose che non so dove mettere
 

src/bootloader/stage2/Makefile

@@ -0,0 +1,34 @@
+BUILD_DIR?=build/
+ASM?=nasm
+ASMFLAGS?=-f obj
+CC?=gcc
+CC16?=/usr/bin/watcom/binl/wcc
+CFLAGS16?=
+LD16?=/usr/bin/watcom/binl/wlink
+
+SOURCES_C=$(wildcard *.c)
+SOURCES_ASM=$(wildcard *.asm)
+OBJECTS_C=$(patsubst %.c, $(BUILD_DIR)/stage2/c/%.obj, $(SOURCES_C))
+OBJECTS_ASM=$(patsubst %.asm, $(BUILD_DIR)/stage2/asm/%.obj, $(SOURCES_ASM))
+
+.PHONY: all stage2 clean always
+
+all: stage2
+
+stage2: $(BUILD_DIR)/stage2.bin
+
+$(BUILD_DIR)/stage2.bin: $OBJECTS_ASM $OBJECTS_C
+	$(LD16) NAME $(BUILD_DIR)/stage2.bin FILE \{ $(OBJECTS_ASM) $(OBJECTS_C) \} OPTION_MAP=$(BUILD_DIR)/stage2.map @linker.lnk 
+
+$(BUILD_DIR)/stage2/c/%.obj: %.c always
+	$(CC16) $(CFLAGS16) -fo=$@ $<
+
+$(BUILD_DIR)/stage2/asm/%.obj: %.asm always
+	$(ASM) $(ASMFLAGS) -o $@ $<
+
+always:
+	mkdir -p $(BUILD_DIR)/stage2/c
+	mkdir -p $(BUILD_DIR)/stage2/asm
+
+clean:
+	rm -f $(BUILD_DIR)/stage2.bin

src/bootloader/stage2/stage2.asm

@@ -0,0 +1,56 @@
+org 0x0
+bits 16
+
+
+%define ENDL 0x0D, 0x0A
+
+;Codice del kernel
+start:
+    mov si, msg_helloworld
+    call puts
+	call premi_per_riavviare
+
+.halt:
+    cli
+    hlt
+
+puts:
+    ; save registers we will modify
+    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
+
+;Stringhe
+msg_helloworld: 
+	db 'Hello World dallo stage2 del Bootloader!', ENDL, 0
+
+msg_premi_per_riavviare:
+	db 'Premi un tasto per riavviare...', ENDL, 0
+;Errori
+
+;Variabili
+
+;Cose che non so dove mettere
+premi_per_riavviare:
+	mov si, msg_premi_per_riavviare
+	call puts
+	mov ah, 0
+	int 16h
+	jmp 0FFFFh:0 

src/kernel/Makefile

@@ -0,0 +1,17 @@
+BUILD_DIR?=build/
+ASM?=nasm
+CC?=gcc
+CC16?=/usr/bin/watcom/binl/wcc
+LD16?=/usr/bin/watcom/binl/wlink
+
+.PHONY: all clean
+
+all: kernel
+
+kernel: $(BUILD_DIR)/kernel.bin
+
+$(BUILD_DIR)/kernel.bin:
+	$(ASM) kernel.asm -f bin -o $(BUILD_DIR)/kernel.bin
+
+clean:
+	rm -f $(BUILD_DIR)/kernel.bin