initial commit

build.sh

@@ -0,0 +1,18 @@
+x86_64-elf-as -o entry.o entry.s
+echo "Successfully compiled entry"
+x86_64-elf-gcc -ffreestanding -c -o kernel.o kernel.c -std=gnu11 -Wall -Wextra
+echo "Succesfully compiled kernel"
+x86_64-elf-gcc -ffreestanding -nostdlib -T linker.ld -o os.elf entry.o kernel.o
+echo "Successfully compiled elf with linker"
+echo "Connecting to spyro for remote compile..."
+scp -r iso next@spyro.corp.bbrunson.com:~/OS/
+echo "Successfully transferred elf to spyro"
+echo "Compiling ISO with GRUB..."
+ssh next@spyro.corp.bbrunson.com 'grub-mkrescue -o ~/OS/os.iso ~/OS/iso'
+echo "Successfully compiled OS"
+echo "Transferring compiled ISO..."
+scp -r next@spyro.corp.bbrunson.com:~/OS/os.iso .
+echo "Successfully tranferred compiled ISO"
+echo "= Compilation complete ="
+echo "Booting ISO via QEMU..."
+qemu-system-x86_64 -cdrom os.iso

entry.s

@@ -0,0 +1,7 @@
+    .section .text
+    .globl _start       # Declare _start as global
+    .extern kmain       # Declare the external C function
+
+_start:
+    call kmain         # Call the C kernel entry point
+    hlt                # Halt if kmain returns

iso/boot/grub/grub.cfg

@@ -0,0 +1,5 @@
+set timeout=5
+menuentry "My OS" {
+    multiboot /boot/os.elf
+    boot
+}

kernel.c

@@ -0,0 +1,11 @@
+/* kernel.c */
+#include "multiboot.h"
+
+// Define the kernel entry point. It must be declared extern "C" if you use C++.
+void kmain(void) {
+    // Your kernel initialization and code here.
+    // For example, a simple infinite loop.
+    while (1) {
+        // Optionally, add code to print something to the screen.
+    }
+}

linker.ld

@@ -0,0 +1,24 @@
+ENTRY(_start)
+PHDRS {
+    header PT_LOAD FILEHDR PHDRS ALIGN(4)
+    kernel PT_LOAD FLAGS(5)
+}
+
+SECTIONS
+{
+    /* Place the multiboot header at file offset 0 */
+    . = 0;
+    .multiboot : {
+        KEEP(*(.multiboot))
+    } AT(0) : header
+
+    /* Place the remaining kernel sections starting at 1MB */
+    . = 0x100000;
+    .text : {
+        *(.text*)
+    } : kernel
+
+    .rodata : { *(.rodata*) } : kernel
+    .data   : { *(.data*) }   : kernel
+    .bss    : { *(.bss*) }    : kernel
+}

make

@@ -0,0 +1,14 @@
+CC=x86_64-elf-gcc
+CFLAGS=-ffreestanding -O2 -Wall -Wextra
+LDFLAGS=-T linker.ld
+
+all: os.bin
+
+%.o: %.c
+    $(CC) $(CFLAGS) -c $< -o $@
+
+os.bin: boot.o kernel.o
+    $(CC) $(LDFLAGS) $^ -o $@
+
+clean:
+    rm -f *.o os.bin

multiboot.h

@@ -0,0 +1,17 @@
+/* multiboot.h */
+#ifndef MULTIBOOT_H
+#define MULTIBOOT_H
+
+#define MULTIBOOT_HEADER_MAGIC       0x1BADB002
+#define MULTIBOOT_HEADER_FLAGS       0x00010003  // Set flags as needed
+#define MULTIBOOT_HEADER_CHECKSUM    -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
+
+// Place the multiboot header in a dedicated section so that the bootloader can find it.
+__attribute__((section(".multiboot")))
+const unsigned int multiboot_header[3] = {
+    MULTIBOOT_HEADER_MAGIC,
+    MULTIBOOT_HEADER_FLAGS,
+    MULTIBOOT_HEADER_CHECKSUM
+};
+
+#endif // MULTIBOOT_H