OS Barebones done

.gitignore

@@ -0,0 +1,6 @@
+CMakeFiles/
+CMakeCache.txt
+Makefile
+cmake_install.cmake
+.vscode/
+./OwOS.bin

build/CMakeLists.txt

@@ -0,0 +1,30 @@
+cmake_minimum_required(VERSION 3.9)
+project(OwOS)
+
+enable_language(ASM)
+
+set(CMAKE_ASM_COMPILER "i686-elf-as")
+set(CMAKE_C_COMPILER "i686-elf-gcc")
+set(CMAKE_CXX_COMPILER "i686-elf-g++")
+
+set(CMAKE_CXX_FLAGS  "-ffreestanding -O2 -fno-rtti -Wno-write-strings -Wno-multichar -Wno-unused-parameter -Wno-overflow -Wno-narrowing -fno-exceptions -Wno-trigraphs ${CMAKE_CXX_FLAGS}")
+set(CMAKE_EXE_LINKER_FLAGS  "-T ../linker.ld -ffreestanding -O2 -nostdlib -lgcc -Wwrite-strings ${CMAKE_EXE_LINKER_FLAGS}")
+
+include_directories(OwOS "../src")
+
+# Kernel source
+file(GLOB KERN_SRC 
+    "../src/*.cpp" 
+    "../src/*.asm" 
+    "../*.asm"
+    "../*.cpp" 
+) 
+
+set(SRCS ${KERN_SRC})
+
+add_executable(OwOS ${SRCS})
+
+set_target_properties(OwOS PROPERTIES OUTPUT_NAME "OwOS.bin")
+
+add_custom_target(iso COMMAND cp OwOS.bin ../iso/boot/OwOS.bin && grub-mkrescue -o OwOS.iso ../iso)
+add_dependencies(iso OwOS)

install-crosscompiler.sh

@@ -0,0 +1,41 @@
+# Install requirements
+sudo apt install build-essential bison flex libgmp3-dev libmpc-dev libmpfr-dev texinfo xorriso grub-pc-bin
+
+# Configuration
+export PREFIX="$HOME/opt/cross"
+export TARGET=i686-elf
+export PATH="$PREFIX/bin:$PATH"
+
+# Create directories
+mkdir $HOME/src
+
+# Download binutils + gcc
+wget https://ftp.nluug.nl/pub/gnu/binutils/binutils-2.31.tar.xz -O $HOME/src/binutils-2.31.tar.xz
+wget https://ftp.gnu.org/gnu/gcc/gcc-8.2.0/gcc-8.2.0.tar.xz -O $HOME/src/gcc-8.2.0.tar.xz
+
+# Decompress
+cd $HOME/src
+tar -xf binutils-2.31.tar.xz
+tar -xf gcc-8.2.0.tar.xz
+
+# Build binutils
+cd $HOME/src
+mkdir build-binutils
+cd build-binutils
+../binutils-2.31/configure --target=$TARGET --prefix="$PREFIX" --with-sysroot --disable-nls --disable-werror
+make -j4
+make install
+
+# Build GCC
+cd $HOME/src
+which -- $TARGET-as || echo $TARGET-as is not in the PATH
+mkdir build-gcc
+cd build-gcc
+../gcc-8.2.0/configure --target=$TARGET --prefix="$PREFIX" --disable-nls --enable-languages=c,c++ --without-headers
+make all-gcc -j4
+make all-target-libgcc -j4
+make install-gcc
+make install-target-libgcc
+
+export PATH="$HOME/opt/cross/bin:$PATH"
+echo "Done!"

iso/boot/grub/grub.cfg

@@ -0,0 +1,7 @@
+set timeout=0
+set default=0
+
+menuentry "OwOS v0.01" {
+	multiboot /boot/OwOS.bin
+    boot
+}

kernel.asm

@@ -0,0 +1,61 @@
+# OwOS
+# Copyright Benjamin Kyd (c) 2019
+
+# declare constants for the multiboot header
+.set ALIGN,    1<<0                     # align loaded modules on page boundaries
+.set MEMINFO,  1<<1                     # provide memory map
+.set FLAGS,    ALIGN | MEMINFO          # this is the Multiboot 'flag' field
+.set MAGIC,    0x1BADB002               #'magic number' lets bootloader find the header
+.set CHECKSUM, -(MAGIC + FLAGS)         # checksum of above, to prove we are multiboot
+
+.section .multiboot
+.align 4
+.long MAGIC
+.long FLAGS
+.long CHECKSUM
+ 
+.section .bss
+.align 16
+stack_bottom:
+.skip 16384   # 16 KiB
+stack_top:
+
+.section .text
+.global _start
+.type _start, @function
+
+_start:
+    # Settup stack
+	mov $stack_top, %esp
+	push %ebx
+	push %eax
+
+    # FPU Config
+    VAL_037F:
+        .hword 0x037F
+    VAL_037E:
+        .hword 0x037E
+    VAL_037A:
+        .hword 0x037A
+    # Configure FPU
+    cli
+    mov %cr0, %eax
+    or $0b00110010, %eax
+    and $0xFFFFFFFB, %eax
+    mov %eax, %cr0
+    fldcw VAL_037F
+    fldcw VAL_037E
+    fldcw VAL_037A
+    fninit
+
+	call kernel_main
+
+	cli
+1:	hlt
+	jmp 1b
+
+_hang:
+    hlt
+    jmp _hang
+
+.size _start, . - _start

kernel.cpp

@@ -0,0 +1,41 @@
+#define TERM_WIDTH 80
+#define TERM_HEIGHT 25
+
+struct VGAChar_t {
+    char c;
+    char foreground:4;
+    char background:4;
+}__attribute__((packed));
+
+VGAChar_t* framebuffer = (VGAChar_t*)0xB8000;
+
+void putcar(int x, int y, char c, char foreground, char background) {
+    framebuffer[(y * TERM_WIDTH) + x].c = c;
+    framebuffer[(y * TERM_WIDTH) + x].foreground = foreground;
+    framebuffer[(y * TERM_WIDTH) + x].background = background;
+}
+
+extern "C"
+
+int kernel_main() {
+
+    for (int x = 0; x < TERM_WIDTH; x++)
+        for (int y = 0; y < TERM_HEIGHT; y++)
+            putcar(x, y, ' ', 0x00, 0x00);
+
+    putcar(0, 0, 'H', 0x01, 0x07);
+    putcar(1, 0, 'A', 0x01, 0x07);
+    putcar(2, 0, 'H', 0x01, 0x07);
+    putcar(3, 0, 'A', 0x01, 0x07);
+    putcar(4, 0, '!', 0x01, 0x07);
+    putcar(5, 0, ' ', 0x01, 0x07);
+    putcar(6, 0, 'P', 0x01, 0x07);
+    putcar(7, 0, 'E', 0x01, 0x07);
+    putcar(8, 0, 'N', 0x01, 0x07);
+    putcar(9, 0, 'I', 0x01, 0x07);
+    putcar(10, 0, 'S', 0x01, 0x07);
+    putcar(11, 0, '!', 0x01, 0x07);
+    
+    for (;;)
+        asm("hlt");
+}

linker.ld

@@ -0,0 +1,49 @@
+/* The bootloader will look at this image and start execution at the symbol
+   designated as the entry point. */
+ENTRY(_start)
+
+/* Tell where the various sections of the object files will be put in the final
+   kernel image. */
+SECTIONS
+{
+	/* Begin putting sections at 1 MiB, a conventional place for kernels to be
+	   loaded at by the bootloader. */
+	. = 1M;
+
+	/* First put the multiboot header, as it is required to be put very early
+	   early in the image or the bootloader won't recognize the file format.
+	   Next we'll put the .text section. */
+	.text BLOCK(4K) : ALIGN(4K)
+	{
+		*(.multiboot)
+		*(.text)
+	}
+
+	/* Read-only data. */
+	.rodata BLOCK(4K) : ALIGN(4K)
+	{
+		*(.rodata)
+	}
+
+	/* Read-write data (initialized) */
+	.data BLOCK(4K) : ALIGN(4K)
+	{
+		*(.data)
+	}
+
+	/* Read-write data (uninitialized) and stack */
+	.bss BLOCK(4K) : ALIGN(4K)
+	{
+		*(COMMON)
+		*(.bss)
+	}
+
+	/* Kernel size detection */
+	.sizedetect BLOCK(4K) : ALIGN(4K)
+	{
+		*(.sizedetect)
+	}
+
+	/* The compiler may produce other sections, by default it will put them in
+	   a segment with the same name. Simply add stuff here as needed. */
+}