Files for part 1, https://www.youtube.com/watch?v=1rnA6wpF0o4

Author: Viktor Engelmann

kernel.cpp

@@ -0,0 +1,28 @@
+
+void printf(char* str)
+{
+    static unsigned short* VideoMemory = (unsigned short*)0xb8000;
+
+    for(int i = 0; str[i] != '\0'; ++i)
+        VideoMemory[i] = (VideoMemory[i] & 0xFF00) | str[i];
+}
+
+
+
+typedef void (*constructor)();
+extern "C" constructor start_ctors;
+extern "C" constructor end_ctors;
+extern "C" void callConstructors()
+{
+    for(constructor* i = &start_ctors; i != &end_ctors; i++)
+        (*i)();
+}
+
+
+
+extern "C" void kernelMain(const void* multiboot_structure, unsigned int /*multiboot_magic*/)
+{
+    printf("Hello World! --- http://www.AlgorithMan.de");
+
+    while(1);
+}

linker.ld

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+ENTRY(loader)
+OUTPUT_FORMAT(elf32-i386)
+OUTPUT_ARCH(i386:i386)
+
+SECTIONS
+{
+  . = 0x0100000;
+
+  .text :
+  {
+    *(.multiboot)
+    *(.text*)
+    *(.rodata)
+  }
+
+  .data  :
+  {
+    start_ctors = .;
+    KEEP(*( .init_array ));
+    KEEP(*(SORT_BY_INIT_PRIORITY( .init_array.* )));
+    end_ctors = .;
+
+    *(.data)
+  }
+
+  .bss  :
+  {
+    *(.bss)
+  }
+
+  /DISCARD/ : { *(.fini_array*) *(.comment) }
+}

loader.s

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+.set MAGIC, 0x1badb002
+.set FLAGS, (1<<0 | 1<<1)
+.set CHECKSUM, -(MAGIC + FLAGS)
+
+.section .multiboot
+    .long MAGIC
+    .long FLAGS
+    .long CHECKSUM
+
+
+.section .text
+.extern kernelMain
+.extern callConstructors
+.global loader
+
+
+loader:
+    mov $kernel_stack, %esp
+    call callConstructors
+    push %eax
+    push %ebx
+    call kernelMain
+
+
+_stop:
+    cli
+    hlt
+    jmp _stop
+
+
+.section .bss
+.space 2*1024*1024; # 2 MiB
+kernel_stack:
+

makefile

@@ -0,0 +1,23 @@
+
+# sudo apt-get install g++ binutils libc6-dev-i386
+
+GCCPARAMS = -m32 -fno-use-cxa-atexit -nostdlib -fno-builtin -fno-rtti -fno-exceptions -fno-leading-underscore
+ASPARAMS = --32
+LDPARAMS = -melf_i386
+
+objects = loader.o kernel.o
+
+
+
+%.o: %.cpp
+	gcc $(GCCPARAMS) -c -o $@ $<
+
+%.o: %.s
+	as $(ASPARAMS) -o $@ $<
+
+mykernel.bin: linker.ld $(objects)
+	ld $(LDPARAMS) -T $< -o $@ $(objects)
+
+install: mykernel.bin
+	sudo cp $< /boot/mykernel.bin
+