Go back to C and adapt codeHEADmasterdevelop

1 files changed, 50 insertions, 0 deletions

diff --git a/kernel/GDT/gdt.c b/kernel/GDT/gdt.c
new file mode 100644
index 0000000..4aae655
--- /dev/null
+++ b/kernel/GDT/gdt.c
@@ -0,0 +1,50 @@
+#include "gdt.h"
+#include "../Helpers/types.h"
+#include "../Helpers/memory.h"
+
+//Declare global vars
+GdtDescriptorStruct GDT_DESCRIPTORS[4];
+GdtPointerStruct GDT_POINTER;
+
+//Adapt parameter to the gdt descriptor structure
+void gdt_initGdtDesc(u32 base, u32 limit, u8 access, u8 flags, GdtDescriptorStruct *Descriptor){
+	Descriptor->limit1 = limit & 0xFFFF;
+	Descriptor->base1 = base & 0xFFFF;
+	Descriptor->base2 = (base & 0xFF0000) >> 16;
+	Descriptor->access = access;
+	Descriptor->limit2 = (limit & 0xF0000 ) >> 16;
+	Descriptor->flags = flags & 0xFF;
+	Descriptor->base3 = (base & 0xFF000000) >> 24;
+}
+
+//Copy the gdt into mémory and load it
+void gdt_loadGdt(){
+
+    //Init default segment
+    gdt_initGdtDesc(0x0,0x0,0x0,0x0, &GDT_DESCRIPTORS[0]);
+
+    //Init code segment
+    gdt_initGdtDesc(0x0,0xFFFFF,0x9A,0x0D, &GDT_DESCRIPTORS[1]);
+
+    //Init data segment
+    gdt_initGdtDesc(0x0,0xFFFFF,0x92,0x0D, &GDT_DESCRIPTORS[2]);
+
+    //Init stack segment
+    gdt_initGdtDesc(0x00B00000,0x00000500,0x96,0x0D, &GDT_DESCRIPTORS[3]);
+
+
+    //Init GDT Pointer
+    GDT_POINTER.size=4*sizeof(GDT_DESCRIPTORS);
+    GDT_POINTER.segment=0x00007E00;
+
+	//Copy Gdt into memory and init registers
+	memcpy((u32)GDT_DESCRIPTORS, (u32)GDT_POINTER.segment, (u32)GDT_POINTER.size);
+
+    //Load the GDT
+    __asm__("lgdtl (%0);"
+            :
+            :"r"(&GDT_POINTER)
+    );
+}
+
+