From 9ef60208fec0c672248023d467f57eecd6e7214f Mon Sep 17 00:00:00 2001
From: =?utf8?q?Duje=20Mihanovi=C4=87?= <duje.mihanovic@skole.hr>
Date: Thu, 16 Sep 2021 16:48:26 +0200
Subject: [PATCH] Also compile kernel as ELF for easier disassembly

---
 Makefile                  | 7 +++++--
 kernel/arch/x86/tty/tty.c | 2 +-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 8d4b365..ce6fccc 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@ CC = i686-elf-gcc
 
 KERNEL_OBJ = kernel/entry.o kernel/arch/x86/tty/tty.o kernel/kernel.o
 
-all: boot.img
+all: boot.img kernel/kernel.elf
 
 boot.img: boot/x86/boot kernel/kernel.bin
 	cat boot/x86/boot kernel/kernel.bin > $@
@@ -14,7 +14,7 @@ boot/x86/boot: boot/x86/boot.s boot/x86/a20.s boot/x86/protected.s boot/x86/prin
 	$(AS) -f bin boot/x86/boot.s -o $@
 
 kernel/kernel.bin: ${KERNEL_OBJ}
-	$(LD) -o $@ -T kernel/linker.ld ${KERNEL_OBJ} --oformat=binary
+	$(LD) -o $@ -T kernel/linker.ld ${KERNEL_OBJ} 
 
 kernel/entry.o: kernel/entry.s
 	$(AS) -f elf kernel/entry.s -o $@
@@ -25,6 +25,9 @@ kernel/arch/x86/tty/tty.o: kernel/arch/x86/tty/tty.c
 kernel/kernel.o: kernel/kernel.c
 	$(CC) -g -o $@ -Iinclude/arch/x86 -ffreestanding -c kernel/kernel.c
 
+kernel/kernel.elf: kernel/kernel.bin
+	$(LD) -o $@ -T kernel/linker.ld ${KERNEL_OBJ} --oformat=elf32-i386
+
 clean:
 	rm boot/x86/boot kernel/kernel.bin ${KERNEL_OBJ} boot.img
 
diff --git a/kernel/arch/x86/tty/tty.c b/kernel/arch/x86/tty/tty.c
index c1bb0a5..d3ef87b 100644
--- a/kernel/arch/x86/tty/tty.c
+++ b/kernel/arch/x86/tty/tty.c
@@ -1,7 +1,7 @@
 #define VGA_WIDTH 80
 #define VGA_HEIGHT 25
 
-char *video_memory = (char *) 0xB8000; /* VGA VRAM starts at 0xB8000 */
+volatile char *video_memory = (char *) 0xB8000; /* VGA VRAM starts at 0xB8000 */
 
 static int cursor_x = 0;
 static int cursor_y = 0;
-- 
2.39.2