1 files changed, 85 insertions, 0 deletions
diff --git a/disk.asm b/disk.asm
new file mode 100644
index 0000000..3e43c48
--- /dev/null
+++ b/disk.asm
@@ -0,0 +1,85 @@
+%ifndef _DISK_ASM
+%define _DISK_ASM
+
+disk_lba_chs:
+	push bp
+	mov bp, sp
+
+	mov ax, word [bp - 2]	; LBA
+
+	mov sp, bp
+	pop bp
+	ret
+
+disk_reset:
+	push bp
+	mov bp, sp
+	pusha
+
+	mov ah, 00h		; reset disk
+	mov dl, [bp + 4]	; disk number
+	int 13h			; BIOS disk service
+	jnc .success
+
+	push error_msg_disk_reset
+	call panic
+
+.success:
+	push msg_disk_reset
+	call puts
+	add sp, 2
+
+	popa
+	mov sp, bp
+	pop bp
+	ret
+
+
+disk_read:
+	push bp
+	mov bp, sp
+
+	push di
+	mov di, 3		; retry counter
+.readloop:
+	push ax
+	push bx
+	push cx
+
+	mov ah, 02h		; BIOS - read disk sectors
+	int 13h			; BIOS disk service
+
+	jnc .success
+
+	push dx
+	call disk_reset
+	add sp, 2
+
+	pop cx
+	pop bx
+	pop ax
+
+	dec di
+	jnz .readloop
+
+	push error_msg_disk_read
+	call panic
+	add sp, 2
+
+.success:
+	pop di
+	mov sp, bp
+	pop bp
+	ret
+
+
+; data
+drive0: dw 0
+
+msg_disk_reset: db "Drive reset successful.", CR, LF, 0
+msg_disk_read: db "Sector read successful.", CR, LF, 0
+
+error_msg_disk_reset: db "Drive reset failed!", CR, LF, 0
+error_msg_disk_read: db "Drive read failed!", CR, LF, 0
+
+%endif ; _DISK_ASM