first commit

Makefile

@@ -0,0 +1,12 @@
+CFLAGS= -m32 -Wfatal-errors -nostdlib -Wno-builtin-declaration-mismatch
+ASFLAGS= --32
+LDFLAGS= -melf_i386 -nostdlib -e loader -T link.ld
+OBJS=kernel.bin
+
+all: $(OBJS)
+kernel.bin: loader.o kernel.o
+	$(LD) $(LDFLAGS) $^ -o $@
+install:
+	cp ./kernel.bin /boot/mykernel.bin
+clean:
+	$(RM) *.o kernel.bin

kernel.c

@@ -0,0 +1,12 @@
+#define SPACE "                                                                                                "
+void puts(char*s)
+{
+	static unsigned short*vram=(unsigned short*)0xb8000;
+	for(int i=0;s[i];++i)
+		vram[i]=(vram[i]&0xff00)|s[i];
+}
+
+void kernelmain(void*multiboot_structure,unsigned magicnumber)
+{
+	puts("Hello and welcome to my first operating system, yo!"SPACE);
+}

link.ld

@@ -0,0 +1,34 @@
+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 = .;
+	}
+
+	.bss :
+	{
+		*(.bss )
+	}
+
+	/DISCARD/ :
+	{
+		*(.fini_array* )
+		*(.comment )
+	}
+}

loader.s

@@ -0,0 +1,30 @@
+.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
+.global loader
+
+loader:
+	mov $kernel_stack, %esp
+	push %eax
+	push %ebx
+	call kernelmain
+.L1:
+	cli
+	hlt
+	jmp .L1
+
+
+.section bss
+.space 2*1024*1024 ; # 2 MiB
+kernel_stack:
+