refactor: decouple i386 specific instruction invocation

[lunaix-os.git] / lunaix-os / kernel / asm / i386 / gdt.c

diff --git a/lunaix-os/kernel/asm/i386/gdt.c b/lunaix-os/kernel/asm/i386/gdt.c
new file mode 100644 (file)
index 0000000..92e31d1
--- /dev/null
+++ b/lunaix-os/kernel/asm/i386/gdt.c
@@ -0,0 +1,30 @@
+#include <arch/i386/gdt.h>
+#include <arch/i386/tss.h>
+#include <lunaix/types.h>
+
+#define GDT_ENTRY 6
+
+u64_t _gdt[GDT_ENTRY];
+u16_t _gdt_limit = sizeof(_gdt) - 1;
+
+void
+_set_gdt_entry(u32_t index, u32_t base, u32_t limit, u32_t flags)
+{
+    _gdt[index] =
+      SEG_BASE_H(base) | flags | SEG_LIM_H(limit) | SEG_BASE_M(base);
+    _gdt[index] <<= 32;
+    _gdt[index] |= SEG_BASE_L(base) | SEG_LIM_L(limit);
+}
+
+extern struct x86_tss _tss;
+
+void
+_init_gdt()
+{
+    _set_gdt_entry(0, 0, 0, 0);
+    _set_gdt_entry(1, 0, 0xfffff, SEG_R0_CODE);
+    _set_gdt_entry(2, 0, 0xfffff, SEG_R0_DATA);
+    _set_gdt_entry(3, 0, 0xfffff, SEG_R3_CODE);
+    _set_gdt_entry(4, 0, 0xfffff, SEG_R3_DATA);
+    _set_gdt_entry(5, (u32_t)&_tss, sizeof(struct x86_tss) - 1, SEG_TSS);
+}
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