From bcff1efe59c6af0af63c408fa36568fa59675779 Mon Sep 17 00:00:00 2001
From: Ain <41307858+nero@users.noreply.github.com>
Date: Sun, 24 Mar 2019 17:59:03 +0000
Subject: [PATCH] Add routine to backup IVT

---
 kernel/intr.asm | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/kernel/intr.asm b/kernel/intr.asm
index 5054a0c..8da59e2 100644
--- a/kernel/intr.asm
+++ b/kernel/intr.asm
@@ -1,3 +1,25 @@
+; out	ds:si	copy of interrupt table
+ivt_backup:
+  push ax
+  push cx
+  push di ; backup original value
+  push ds
+  mov ax, 0x80
+  call malloc
+  push di
+  mov cx, 0x80
+  mov ax, cs
+  mov es, ax
+  mov si, 0x0000
+  mov ds, si
+  rep movsb
+  pop si ; this was di after malloc
+  pop ds
+  pop di ; restore original di
+  pop cx
+  pop ax
+  ret
+
 ; set item in interrupt vector table
 ; in:	bx	interrupt number
 ;	ds:dx	new handler address