VV的操作系统笔记（一）操作系统I SeeYou!!!!

apt-get install docker docker.io docker-compose qemu virtualbox 

一个魔术块：包含了魔数[0x1BADB002]，是多引导项头结构的定义值。
一个标志块：我们不关心这个块的内容，我们简单设定为0。
一个校检块：校检块，魔术块和标志块的数值的总和必须是0。

.set MAGIC, 0x1badb002;GRUB魔术块
.set FLAGS, (1<<0 | 1<<1);GRUB标志块
.set CHECKSUM, -(MAGIC + FLAGS);校验块

.section .multboot
	.long MAGIC
	.long FLAGS
	.long CHECKSUM
.section .text
.extern kernel_main;导入kernel_main
.extern system_constructors;导入系统构造函数
.global laoder

loader:
	mov $kernel_stack, %esp
	call system_constructors
	push %eax
	push %ebx
	call kernel_main

stop:
	cli
	hlt
	jmp stop

.section .bss
.space 2*1024*1024
kernel_stack:

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

GCCPARAMS = -m32 -W -fno-use-cxa-atexit -nostdlib -fno-builtin -fno-builtin -fno-rtti -fno-exceptions -fno-leading-underscore
ASPPARAMS = --32
LDPARAMS = -melf_i386
GCC = g++
ASM = as
LINKER = ld
CFLAGS = -o $@ -c $<
ASMFLAGS = -o $@ $<
LINKERFLAGS = -T $< -o $@ 

objects = boot.o kernel.o

%.o: %.c
	$(GCC) $(GCCPARAMS) $(CFLAGS)
	
%.o: %.s
	$(ASM) $(ASPPARAMS) $(ASMFLAGS)
	
kernel_lab.bin: linker.ld $(objects)
	$(LINKER) $(LINKERFLAGS) $(objects)
	
all: kernel_lab.bin
	echo "build successed"
clean: 
	rm -rf *.o
	rm -rf *.out
	rm -rf iso
	rm -rf *.iso
	rm -rf *.bin
	
rebuild: clean all
	echo "rebuild"
	
install: kernel_lab.bin
	sudo cp $< /boot/kernel_lab.bin

kernel_lab.iso: rebuild
	mkdir iso
	mkdir iso/boot
	mkdir iso/boot/grub
	cp kernel_lab.bin iso/boot/
	cp boot/grub.cfg iso/boot/grub/grub.cfg
	grub-mkrescue -o $@ iso
	rm -rf iso
	
kernel_vm: kernel_lab.iso
	(killall virtualbox) || true
	virtualbox -startvm "kernel_lab" &

#include "kernel.h"
//因为我们的操作系统没有TTY IO，所以我们需要重新写一个printf函数
extern "C" void  printf(char *str){
	u_short *monitor_io_memory=(u_short *)0xb8000;//注意！重点来啦！0xb8000内存地址是显示器地址，往这里写数据就直接能够输出到屏幕上
	for(int i=0;str[i]!='\0';++i){
		//写入字符串，取或0xff00的意思是我们需要把屏幕高四位拉低，否则就是黑色的字体，黑色的字体黑色的屏幕是啥也看不到的
		monitor_io_memory[i]=(monitor_io_memory[i] & 0xff00) | str[i];
	}
}
//操作系统构造函数委托方法
typedef void(*constructor)();
//全局定义构造委托
constructor start_ctors;
//全局定义析构委托
constructor end_ctors;

//轮询函数，并且执行
extern "C" void system_constructors(){
	for(constructor* i=&start_ctors;i!=&end_ctors;i+=1){
		(*i)();
	}
}
//操作系统主启动函数，这里我们打印一个字符串然后让操作系统进入等待
extern "C" void  kernel_main(const void *multiboot_structure,u_int magicnumber){
	printf("Hello Pulsar-V");
	while(1);
}

set timeout=10 #超时时间
set default=0 #默认启动项
menuentry "PulsarV's OS"	{
	multiboot /boot/kernel_lab.bin
	boot
}

grub-mkrescue: warning: Your xorriso doesn't support `--grub2-boot-info'. Some features are disabled

sudo apt-get install xorriso

grub-mkrescue -o kernel_lab.iso iso

make kernel_vm