From 6becd918de4c0253e9446262277a9817d1189603 Mon Sep 17 00:00:00 2001
From: Aaron Klingaman <alk@cs.princeton.edu>
Date: Tue, 15 Mar 2005 21:57:06 +0000
Subject: [PATCH] a simple boot loader that will be copied to all disks that
 outputs a message telling the user that the machine requires a boot cd

---
 dummy_bootloader/Makefile           | 17 +++++++++++
 dummy_bootloader/dummy_bootloader.S | 44 +++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 dummy_bootloader/Makefile
 create mode 100644 dummy_bootloader/dummy_bootloader.S

diff --git a/dummy_bootloader/Makefile b/dummy_bootloader/Makefile
new file mode 100644
index 0000000..6268133
--- /dev/null
+++ b/dummy_bootloader/Makefile
@@ -0,0 +1,17 @@
+all: dummy_bootloader
+
+dummy_bootloader: dummy_bootloader.S
+	nasm $< -o $@
+
+testbootdisk: dummy_bootloader
+	$(shell dd if=/dev/zero of=testbootdisk bs=512 count=2880)
+
+run: testbootdisk
+	$(shell dd if=dummy_bootloader of=testbootdisk conv=notrunc)
+	$(shell qemu -fda testbootdisk -boot a)
+
+clean:
+	rm -f dummy_bootloader
+	rm -f testbootdisk
+
+.phony: all run clean
diff --git a/dummy_bootloader/dummy_bootloader.S b/dummy_bootloader/dummy_bootloader.S
new file mode 100644
index 0000000..c8f1512
--- /dev/null
+++ b/dummy_bootloader/dummy_bootloader.S
@@ -0,0 +1,44 @@
+SCREEN_COLS     equ 80
+SCREEN_ROWS     equ 25
+STACK_SEGMENT   equ 09000h	; top of memory
+STACK_SIZE      equ 00fffh	; 4K - 1 bytes of stack
+	
+TEXT_COLOR	equ 0x07	; white on black
+
+	jmp 07c0h:start
+
+message		db "PlanetLab nodes require a boot cd at all times to function.",0
+	
+start:
+	mov ax, cs
+	mov ds, ax
+	mov es, ax
+	
+	mov sp, STACK_SEGMENT	; setup stack (not really used)
+	mov ss, sp
+	mov sp, STACK_SIZE
+
+	;; clear out the screen, using the scroll down bios int.
+	mov ah, 0x07		; for int 0x10, 0x07 is scroll down window
+	mov al, 0 		; entire window
+	mov cx, 0		; upper left corner = (0,0)
+	mov dh, SCREEN_ROWS	; row of bottom
+	mov dl,	SCREEN_COLS	; column of right
+	mov bh, 7
+	int 10h			
+	
+	mov si, message
+
+strout: lodsb
+	cmp al, 0
+	je done
+	mov ah, 0x0E		; for int 0x10, 0xOE is char out
+	mov bx, TEXT_COLOR
+	int 0x10
+	jmp strout
+
+done:	
+	jmp done
+	
+	times 510 - ($ - $$) db 0 ;  last two bytes are magic for x86 boot sectors
+	dw 0aa55h
-- 
2.43.0