Fix: Fixed QEMU and Bootloader errors (started from 32-bit -> 64-bit)

boot.asm

@@ -21,6 +21,18 @@ _start:
     mov eax, pml4_table
     mov cr3, eax            ; Load the PML4 table into CR3
 
+    ; Link PML4 -> PDPT
+    mov dword [pml4_table], pdpt_table + 0x3
+    mov dword [pml4_table + 4], 0x0
+
+    ; Link PDPT -> PD
+    mov dword [pdpt_table], pd_table + 0x3
+    mov dword [pdpt_table + 4], 0x0
+
+    ; Link PD -> 2MB Physical Page 0
+    mov dword [pd_table], 0x83
+    mov dword [pd_table + 4], 0x0
+
     mov eax, cr4
     or eax, 0x20            ; Enable PAE
     mov cr4, eax
@@ -45,15 +57,6 @@ kernel_stack_bottom:
     resb 16 * 1024
 kernel_stack_top:
 
-gdt_ptr:
-    dw 0                 ; Limit (set by linker/code later)
-    dq 0                 ; Base Address (set by linker/code later)
-gdt_start:               ; Start of the actual GDT entries
-    ; Entry 0: Null Descriptor
-    dq 0x0000000000000000
-    dq 0x00AF9A000000FFFF
-    dq 0x00AF92000000FFFF
-gdt_end:
 
 pml4_table:
     ; Define a simple PML4 table here (identity mapping for simplicity)
@@ -61,6 +64,25 @@ pml4_table:
     resb 4096            ; Reserve 4 KB for the PML4 table 
 pml4_end:
 
+pdpt_table:
+    resb 4096            ; Reserve 4 KB for the PDPT table 
+pdpt_end:
+
+pd_table:
+    resb 4096            ; Reserve 4 KB for the PD table 
+pd_end:
+
+section .data
+gdt_ptr:
+    dw (gdt_end - gdt_start - 1)                 ; Limit (set by linker/code later)
+    dq gdt_start                 ; Base Address (set by linker/code later)
+gdt_start:               ; Start of the actual GDT entries
+    ; Entry 0: Null Descriptor
+    dq 0x0000000000000000
+    dq 0x00AF9A000000FFFF
+    dq 0x00AF92000000FFFF
+gdt_end:
+
 section .text
 [bits 64] ; Tell NASM to assemble in 64-bit mode
 

build.sh

@@ -1,8 +1,8 @@
 echo ">>> Compiling bootloader"
-nasm boot.asm -o boot.o -f elf64
+nasm boot.asm -o boot.o -f elf32
 
 echo ">>> Compiling kernel"
-gcc kernel.c -o kernel.o -c -m64 -ffreestanding -nostdlib
+gcc kernel.c -o kernel.o -c -m32 -ffreestanding -nostdlib -no-pie
 
 echo ">>> Linking kernel"
-ld -T linker.ld -o SoraOS boot.o kernel.o
+gcc -m32 -nostdlib -no-pie -T linker.ld -o SoraOS boot.o kernel.o

linker.ld

@@ -1,3 +1,4 @@
+OUTPUT_FORMAT(elf32-i386)
 ENTRY(_start)
 
 SECTIONS