From 7a912d1b668ab86ffe088eca3ac7e6f78a04a0c5 Mon Sep 17 00:00:00 2001
From: Tyler Murphy <=>
Date: Mon, 17 Jul 2023 19:34:52 -0400
Subject: refactoring

---
 kernel/src/arch/i686/gdt.asm | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 kernel/src/arch/i686/gdt.asm

(limited to 'kernel/src/arch/i686/gdt.asm')

diff --git a/kernel/src/arch/i686/gdt.asm b/kernel/src/arch/i686/gdt.asm
new file mode 100644
index 0000000..ea8a86b
--- /dev/null
+++ b/kernel/src/arch/i686/gdt.asm
@@ -0,0 +1,42 @@
+global load_gdt
+
+%macro gdt_entry 4
+	db %2 & 0xff
+	db (%2 >> 8) & 0xff
+	db %1 & 0xff
+	db (%1 >> 8) & 0xff
+	db (%1 >> 16) & 0xff
+	db %3
+	db ((%2 >> 16) & 0x0f) | (%4 << 4)
+	db (%1 >> 24) & 0xff
+%endmacro
+
+section .rodata
+align 16
+gdt_start:
+gdt_entry 0, 0, 0, 0
+gdt_entry 0, 0xFFFFF, 0x9A, 0xC
+gdt_entry 0, 0xFFFFF, 0x92, 0xC
+gdt_end:
+gdt_descriptor:
+	dw gdt_end - gdt_start - 1
+	dd gdt_start
+
+
+section .text
+align 8
+load_gdt:
+	cli
+	lgdt [gdt_descriptor]
+    mov eax, cr0
+    or al, 1
+    mov cr0, eax
+	mov ax, 0x10
+	mov ds, ax
+	mov ss, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+	jmp 0x08:after_gdt
+after_gdt:
+    ret
-- 
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