From 28301499381cb541eec4eb99f61e3d1a193c5a2d Mon Sep 17 00:00:00 2001
From: Robin Krahl <robin.krahl@ireas.org>
Date: Mon, 6 Mar 2017 02:15:28 +0100
Subject: gdt: expose code segment offset in GDT

gdt_get_code_offset() returns the offset of the code segment in the GDT
relative to the address of the GDT itself.  This offset is for example
required when setting the interrupt desriptor table.
---
 core/gdt.c           | 5 +++++
 include/garmos/gdt.h | 1 +
 2 files changed, 6 insertions(+)

diff --git a/core/gdt.c b/core/gdt.c
index 708e2c5..b59bf9e 100644
--- a/core/gdt.c
+++ b/core/gdt.c
@@ -74,3 +74,8 @@ void gdt_init(void)
 
 	gdtset(gdtp);
 }
+
+uint16_t gdt_get_code_offset(void)
+{
+	return GDT_SGMT_CODE * sizeof(*gdt);
+}
diff --git a/include/garmos/gdt.h b/include/garmos/gdt.h
index b49f42d..d353437 100644
--- a/include/garmos/gdt.h
+++ b/include/garmos/gdt.h
@@ -18,5 +18,6 @@
 #include <garmos/types.h>
 
 void gdt_init(void);
+uint16_t gdt_get_code_offset(void);
 
 #endif
-- 
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