From 6abd515c051b6dcb545e1033ff129aaaf7293917 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Sun, 10 May 2020 13:35:43 +0200
Subject: Added basic spinlock

---
 src/kernel/io/io.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/kernel/io/io.c b/src/kernel/io/io.c
index 2d9d009..dfd9efa 100644
--- a/src/kernel/io/io.c
+++ b/src/kernel/io/io.c
@@ -66,6 +66,14 @@ void outl(u16 port, u32 data)
 	asm volatile("outl %0, %1" ::"a"(data), "Nd"(port));
 }
 
+void spinlock(int *ptr)
+{
+	int prev;
+	do
+		asm volatile("lock xchgl %0,%1" : "=a"(prev) : "m"(*ptr), "a"(1));
+	while (prev);
+}
+
 void init_serial()
 {
 	outb(0x3f8 + 1, 0x00);
-- 
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