Virtual memory & paging

[lunaix-os.git] / lunaix-os / includes / arch / x86 / gdt.h

diff --git a/lunaix-os/includes/arch/x86/gdt.h b/lunaix-os/includes/arch/x86/gdt.h
new file mode 100644 (file)
index 0000000..bb2fa27
--- /dev/null
+++ b/lunaix-os/includes/arch/x86/gdt.h
@@ -0,0 +1,56 @@
+#ifndef __LUNAIX_GDT_H 
+#define __LUNAIX_GDT_H 1
+
+#define SD_TYPE(x)              (x << 8)
+#define SD_CODE_DATA(x)         (x << 12)
+#define SD_DPL(x)               (x << 13)
+#define SD_PRESENT(x)           (x << 15)
+#define SD_AVL(x)               (x << 20)
+#define SD_64BITS(x)            (x << 21)
+#define SD_32BITS(x)            (x << 22)
+#define SD_4K_GRAN(x)           (x << 23)
+
+#define SEG_LIM_L(x)            (x & 0x0ffff)
+#define SEG_LIM_H(x)            (x & 0xf0000)
+#define SEG_BASE_L(x)           ((x & 0x0000ffff) << 16)
+#define SEG_BASE_M(x)           ((x & 0x00ff0000) >> 16)
+#define SEG_BASE_H(x)            (x & 0xff000000)
+
+#define SEG_DATA_RD         0x00 // Read-Only
+#define SEG_DATA_RDA        0x01 // Read-Only, accessed
+#define SEG_DATA_RDWR       0x02 // Read/Write
+#define SEG_DATA_RDWRA      0x03 // Read/Write, accessed
+#define SEG_DATA_RDEXPD     0x04 // Read-Only, expand-down
+#define SEG_DATA_RDEXPDA    0x05 // Read-Only, expand-down, accessed
+#define SEG_DATA_RDWREXPD   0x06 // Read/Write, expand-down
+#define SEG_DATA_RDWREXPDA  0x07 // Read/Write, expand-down, accessed
+#define SEG_CODE_EX         0x08 // Execute-Only
+#define SEG_CODE_EXA        0x09 // Execute-Only, accessed
+#define SEG_CODE_EXRD       0x0A // Execute/Read
+#define SEG_CODE_EXRDA      0x0B // Execute/Read, accessed
+#define SEG_CODE_EXC        0x0C // Execute-Only, conforming
+#define SEG_CODE_EXCA       0x0D // Execute-Only, conforming, accessed
+#define SEG_CODE_EXRDC      0x0E // Execute/Read, conforming
+#define SEG_CODE_EXRDCA     0x0F // Execute/Read, conforming, accessed
+
+#define SEG_R0_CODE         SD_TYPE(SEG_CODE_EXRD) | SD_CODE_DATA(1) | SD_DPL(0) | \
+                            SD_PRESENT(1) | SD_AVL(0) | SD_64BITS(0) | SD_32BITS(1) | \
+                            SD_4K_GRAN(1)
+
+#define SEG_R0_DATA         SD_TYPE(SEG_DATA_RDWR) | SD_CODE_DATA(1) | SD_DPL(0) | \
+                            SD_PRESENT(1) | SD_AVL(0) | SD_64BITS(0) | SD_32BITS(1) | \
+                            SD_4K_GRAN(1)
+
+#define SEG_R3_CODE         SD_TYPE(SEG_CODE_EXRD) | SD_CODE_DATA(1) | SD_DPL(3) | \
+                            SD_PRESENT(1) | SD_AVL(0) | SD_64BITS(0) | SD_32BITS(1) | \
+                            SD_4K_GRAN(1)
+
+#define SEG_R3_DATA         SD_TYPE(SEG_DATA_RDWR) | SD_CODE_DATA(1) | SD_DPL(3) | \
+                            SD_PRESENT(1) | SD_AVL(0) | SD_64BITS(0) | SD_32BITS(1) | \
+                            SD_4K_GRAN(1)
+                            
+
+void
+_init_gdt();
+
+#endif