Jump to test kernel

Makefile

@@ -2,12 +2,13 @@ run_kernel: compile_kernel
 	qemu-system-i386 -kernel target/kernel.bin
 
 compile_kernel:
-	nasm -felf32 kernel/boot.asm -o target/boot.o
+	nasm -f bin kernel/boot.asm -o target/kernel_boot.o
 	i686-elf-gcc -c kernel/kernel.c -o target/kernel.o -std=gnu99 -ffreestanding -O2 -Wall -Wextra
-	i686-elf-gcc -T kernel/linker.ld -o target/kernel.bin -ffreestanding -O2 -nostdlib target/boot.o target/kernel.o -lgcc
+	i686-elf-gcc -T kernel/linker.ld -o target/kernel.bin -ffreestanding -O2 -nostdlib target/kernel_boot.o target/kernel.o -lgcc
 
 compile_bootloader:
 	rm -rf target/boot.bin
+	nasm -f bin bootloader/test_kernel.asm -o target/kernel.bin
 	nasm -f bin -o target/boot.bin bootloader/main.asm
 
 run_bootloader: compile_bootloader

bootloader/main.asm

@@ -190,17 +190,71 @@ jmp .end
 
 .a20_enabled:
 
+; disable interrupts
+cli
 
+; reset ds
+xor ax, ax
+mov ds, ax
+
+; load the GDT
+lgdt [.gdt_desc]
+
+; switch to protected mode
+mov eax, cr0
+or eax, 1
+mov cr0, eax
+
+; jump to 32 bit code
+jmp 0x08:.clear_pipe
+
+[BITS 32]
+.clear_pipe:
+
+; set Data Segment and Stack segment
+mov ax, 10h
+mov ds, ax
+mov ss, ax
+
+; set up stack
+mov esp, 0x090000
+
+jmp 0x08:0x8000
 
 .end:
-hlt
 jmp .end
 
 .data:
 .str_no_A20:
-db "A20 not enabled..."
+db "A20 not enabled"
+db 0
 
 
+.gdt:
+dd 0
+dd 0
+
+dw 0FFFFh
+dw 0
+db 0
+db 10011010b
+db 11001111b
+db 0
+
+dw 0FFFFh
+dw 0
+db 0
+db 10010010b
+db 11001111b
+db 0
+.gdt_end:
+
+
+
+.gdt_desc:
+dw .gdt_end - .gdt - 1
+dd .gdt
+
 ; print padding nullbytes
 times 510 - ($ - $$) db 0
 

bootloader/test_kernel.asm

@@ -0,0 +1,9 @@
+[bits 32]
+
+mov byte [ds:0B8000h], 0h      ; Move the ASCII-code of 'P' into first video memory
+mov byte [ds:0B8001h], 0h      ; Assign a color code
+
+.loop:
+inc byte [ds:0B8000h]
+inc byte [ds:0B8001h]
+jmp .loop