From f30433dd27cc6959b0605a2e43a126da77d9d027 Mon Sep 17 00:00:00 2001
From: Jarkko Toivanen <jt@jakest.us>
Date: Mon, 12 Jun 2023 11:46:47 +0300
Subject: [PATCH] I guess it barely prints a thing

---
 .gitignore  |  2 ++
 Makefile    | 13 +++++++++++++
 README.md   |  9 +++++++++
 kernel.c    | 12 ++++++++++++
 start32.asm | 43 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 79 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Makefile
 create mode 100644 README.md
 create mode 100644 kernel.c
 create mode 100644 start32.asm

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..e494714
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.elf
+*.o
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..77b84cc
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,13 @@
+all: kernel-i386.elf
+clean:
+	rm *.o *.elf
+
+start32.o: start32.asm
+	fasm start32.asm
+kernel.o: kernel.c
+	../tinycc/tcc -m32 -c kernel.c
+kernel-i386.elf: kernel.o start32.o
+	../tinycc/tcc -m32 -nostdlib -Wl,-Ttext,0x100000 start32.o kernel.o -o kernel-i386.elf
+
+qemu: kernel-i386.elf
+	qemu-system-i386 -kernel kernel-i386.elf
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..3e1702f
--- /dev/null
+++ b/README.md
@@ -0,0 +1,9 @@
+# KoalemOS
+Multiboot compatible stupid useless OS-like project.
+## Compatibility
+32bit x86 legacy BIOS system
+## Building
+FASM and TinyCCompiler are used.
+TCC might need manual compilation for 32bit crosscompilation
+on 64bit systems.
+Just download the source and `make cross` or something.
diff --git a/kernel.c b/kernel.c
new file mode 100644
index 0000000..7e87560
--- /dev/null
+++ b/kernel.c
@@ -0,0 +1,12 @@
+void kmain (void) {
+    *((unsigned char *) 0xB8000) = 'H';
+    *((unsigned char *) 0xB8001) = 0x1F;
+    *((unsigned char *) 0xB8002) = 'E';
+    *((unsigned char *) 0xB8003) = 0x1F;
+    *((unsigned char *) 0xB8004) = 'L';
+    *((unsigned char *) 0xB8005) = 0x1F;
+    *((unsigned char *) 0xB8006) = 'L';
+    *((unsigned char *) 0xB8007) = 0x1F;
+    *((unsigned char *) 0xB8008) = 'O';
+    *((unsigned char *) 0xB8009) = 0x1F;
+}
diff --git a/start32.asm b/start32.asm
new file mode 100644
index 0000000..257691d
--- /dev/null
+++ b/start32.asm
@@ -0,0 +1,43 @@
+;  Tutorial: A small kernel with Fasm & TCC
+;  By Tommy.
+ 
+        format elf
+        use32
+ 
+;
+; Equates
+;
+MULTIBOOT_PAGE_ALIGN	    equ (1 shl 0)
+MULTIBOOT_MEMORY_INFO	    equ (1 shl 1)
+MULTIBOOT_AOUT_KLUDGE	    equ (1 shl 16)
+MULTIBOOT_HEADER_MAGIC	    equ 0x1BADB002
+MULTIBOOT_HEADER_FLAGS	    equ MULTIBOOT_PAGE_ALIGN or MULTIBOOT_MEMORY_INFO
+MULTIBOOT_CHECKSUM          equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
+
+
+;
+; Multiboot header
+;
+.multiboot: align 4
+	dd MULTIBOOT_HEADER_MAGIC
+	dd MULTIBOOT_HEADER_FLAGS
+	dd MULTIBOOT_CHECKSUM
+
+
+section '.bss' writable align 16
+	stack_bottom:
+	rb 16384
+	stack_top:
+
+        section '.text' executable 
+;
+; Kernel entry point.
+;
+        public  _start
+        extrn   kmain
+_start:
+        ; Call the main kernel function.
+        call    kmain
+ 
+@@:
+        jmp     @b