From ad56eb28f0614db4b7656ade390f1c79b446cbc9 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Sat, 10 Jul 2021 15:51:54 +0200
Subject: A20, E820h, Real Mode Emulation

---
 src/loader/gdt.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 src/loader/gdt.c

(limited to 'src/loader/gdt.c')

diff --git a/src/loader/gdt.c b/src/loader/gdt.c
new file mode 100644
index 0000000..853b793
--- /dev/null
+++ b/src/loader/gdt.c
@@ -0,0 +1,49 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#include <gdt.h>
+
+static struct gdt_desc gdt_descs[] = { { 0 },
+
+				       { .limit = 0xffff,
+					 .base_low = 0x0000,
+					 .base_mid = 0x00,
+					 .access = 0x9a,
+					 .granularity = 0x00,
+					 .base_hi = 0x00 },
+
+				       { .limit = 0xffff,
+					 .base_low = 0x0000,
+					 .base_mid = 0x00,
+					 .access = 0x92,
+					 .granularity = 0x00,
+					 .base_hi = 0x00 },
+
+				       { .limit = 0xffff,
+					 .base_low = 0x0000,
+					 .base_mid = 0x00,
+					 .access = 0x9a,
+					 .granularity = 0xcf,
+					 .base_hi = 0x00 },
+
+				       { .limit = 0xffff,
+					 .base_low = 0x0000,
+					 .base_mid = 0x00,
+					 .access = 0x92,
+					 .granularity = 0xcf,
+					 .base_hi = 0x00 },
+
+				       { .limit = 0x0000,
+					 .base_low = 0x0000,
+					 .base_mid = 0x00,
+					 .access = 0x9a,
+					 .granularity = 0x20,
+					 .base_hi = 0x00 },
+
+				       { .limit = 0x0000,
+					 .base_low = 0x0000,
+					 .base_mid = 0x00,
+					 .access = 0x92,
+					 .granularity = 0x00,
+					 .base_hi = 0x00 } };
+
+REAL struct gdtr gdt = { sizeof(gdt_descs) - 1, (u32)gdt_descs, 0 };
-- 
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