Initial source

1 files changed, 53 insertions, 0 deletions

diff --git a/i386/util/i16/i16_gdt_init_temp.c b/i386/util/i16/i16_gdt_init_temp.c
new file mode 100644
index 0000000..14f2d0e
--- /dev/null
+++ b/i386/util/i16/i16_gdt_init_temp.c
@@ -0,0 +1,53 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <mach/machine/code16.h>
+#include <mach/machine/seg.h>
+
+#include "vm_param.h"
+#include "cpu.h"
+
+
+CODE16
+
+/* This 16-bit function initializes CPU 0's GDT
+   just enough to get in and out of protected (and possibly paged) mode,
+   with all addresses assuming identity-mapped memory.  */
+void i16_gdt_init_temp()
+{
+	/* Create temporary kernel code and data segment descriptors.
+	   (They'll be reinitialized later after paging is enabled.)  */
+	i16_fill_gdt_descriptor(&cpu[0], KERNEL_CS,
+				boot_image_pa, 0xffffffff,
+				ACC_PL_K|ACC_CODE_R, SZ_32);
+	i16_fill_gdt_descriptor(&cpu[0], KERNEL_DS,
+				boot_image_pa, 0xffffffff,
+				ACC_PL_K|ACC_DATA_W, SZ_32);
+	i16_fill_gdt_descriptor(&cpu[0], KERNEL_16_CS,
+				boot_image_pa, 0xffff,
+				ACC_PL_K|ACC_CODE_R, SZ_16);
+	i16_fill_gdt_descriptor(&cpu[0], KERNEL_16_DS,
+				boot_image_pa, 0xffff,
+				ACC_PL_K|ACC_DATA_W, SZ_16);
+}
+