From 247a79f26485eaa062f1cdd4545a3bfe6cd6ca81 Mon Sep 17 00:00:00 2001
From: Niklas Halle <niklas@niklashalle.net>
Date: Tue, 5 May 2020 16:23:02 +0200
Subject: sleep

---
 01_exercise/bootloader.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/01_exercise/bootloader.c b/01_exercise/bootloader.c
index 1ba5786..e891116 100644
--- a/01_exercise/bootloader.c
+++ b/01_exercise/bootloader.c
@@ -33,7 +33,20 @@ char getc() {
     return ret;
 }
 
+void sleep(short ms) {
+    long ys = ms * 1000;
+    short cx = ys >> 16;
+    short dx = ys;
+
+    // http://www.ctyme.com/intr/rb-1525.htm : Int 15/AH=86h bios wait
+    char ah = 0x86;
+    char al = 0x00;
+    short command = ah << 8 | al;
+
+    asm volatile("int $0x15;" : : "a"(command), "cx"(cx), "dx"(dx));
+}
+
 void main(void) {
     print("Hello!");
-    put(getc());
-}
+    print("\n\r > ");
+}
\ No newline at end of file
-- 
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