1 files changed, 121 insertions, 0 deletions
diff --git a/src/boot/stage1_functions.asm b/src/boot/stage1_functions.asm
new file mode 100644
index 0000000..bdb2aac
--- /dev/null
+++ b/src/boot/stage1_functions.asm
@@ -0,0 +1,121 @@
+; IN dx: hex value to print	
+print_hex:
+	push bx
+	push si
+	mov si, HEX_TEMPLATE
+	mov bx, dx
+	shr bx, 12
+	mov bx, [HEXABET+bx]
+	mov [HEX_TEMPLATE+2], bl
+	mov bx, dx
+	and bx, 0x0FFF
+	shr bx, 8
+	mov bx, [HEXABET+bx]
+	mov [HEX_TEMPLATE+3], bl
+	mov bx, dx
+	and bx, 0x00FF
+	shr bx, 4
+	mov bx, [HEXABET+bx]
+	mov [HEX_TEMPLATE+4], bl
+	mov bx, dx
+	and bx, 0x000F
+	mov bx, [HEXABET+bx]
+	mov [HEX_TEMPLATE+5], bl
+	call print_string
+	pop si
+	pop bx
+	ret
+
+HEX_TEMPLATE:
+	db '0x???? ', 0
+
+HEXABET:
+	db '0123456789ABCDEF'
+
+print_newline:
+	push ax
+	mov al, 10
+	call print_char
+	mov al, 13
+	call print_char
+	pop ax
+	ret
+
+; IN si
+print_string:
+	push ax
+.loop:
+	lodsb
+	cmp al, 0
+	je .fini
+	call print_char
+	jmp .loop
+.fini:
+	pop ax
+	ret
+
+; IN al: character to print
+; MOD ah
+print_char:
+	mov ah, 0x0e
+	int 0x10
+	ret
+
+fat_cursor:
+	push ax
+	push cx
+	mov ah, 0x01
+	mov cx, 0x0007
+	int 0x10
+	pop cx
+	pop ax
+	ret
+
+; OUT: current row
+current_row:
+	push ax
+	push bx
+	push cx
+	mov ah, 0x03
+	mov bh, 0
+	int 0x10
+	pop cx
+	pop bx
+	pop ax
+	ret
+
+; IN dl: drive to read from
+read_stage2_from_disk:
+	mov ah, 0x02			; read sectors from drive
+	
+	mov al, 3			; read 3 sectors of stage 2
+	mov ch, 0			; select first cylinder
+	mov dh, 0			; first head
+	mov cl, 2			; second sector after boot sector
+	
+	mov bx, 0			; where to store the data
+	mov es, bx
+	mov bx, 0x7e00			; 512 bytes after first sector
+		
+	int 0x13
+	
+	jc .read_error
+	
+	cmp al, 3			; 3 sectors read?
+	jne .short_read			; if not, short read
+	
+	ret
+	
+.read_error:
+	mov si, DISK_ERROR
+	call print_string
+	mov dh, 0
+	mov dl, ah
+	call print_hex
+	jmp $
+
+.short_read:
+	mov si, SHORT_READ
+	call print_string
+	jmp $
+