main.c

用于汇编领域的,运用于OS的MAIN函数.基于硬件基础的源代码

#include "hos.h"

void start_kernel(void)
{
	int a,i; float b=3.0;
	long esp; short ss;
	unsigned long buf[128]; char bint;
	unsigned long *pgdir_loc;

	init_screen();
	printk("hos8:start kernel starts\n"); 
	__asm__ ("lss swapper_stack_start, %%esp\n\t"
            "jmp L1\n\t"
	    "swapper_stack_start:\n\t"
	    ".long (init_task_union + 8192)\n\t"
	    ".long 0x10\n\t"
	    "L1:\n"::);
	printk("init_task_union is at:%x \n", init_task_union);
	__asm__ ("movl %%esp, %0\n\t"
		 "movl %%ss, %1\n\t"
		 :"=m"(esp),"=m"(ss):);
	printk("esp is %x and ss is %x\n", esp, ss);
	//init_screen();
	tss_init();  // be ready for int
	//init_mm();
	//make_init_task();
	//current=init_task;
	init_interrupt();
	bint=inbyte(0x21);
	printk("after init interr. blocked ints:%x\n",bint);
	//init_timer(); we want to activate timer at tha last moment
	bint=inbyte(0x21);
	printk("after init timer. blocked ints:%x\n",bint);
	init_kbd();
	bint=inbyte(0x21);
	printk("after init kbd. blocked ints:%x\n",bint);

	// unmask all irqs
	// first read what ints are served
	//a=inbyte(0x21);
	//printk("21h is %x\n",a);
	//for(a=0;a<16;a++) unmask_irq(a);
	//a=inbyte(0x21);
	//printk("and now 21h is %x\n",a);

	init_floppy();
	bint=inbyte(0x21);
	printk("after init floppy. blocked ints:%x\n",bint);

	// check currently serviced interrupts
	//outbyte(0x20, 0x9);
	//a=inbyte(0x20);
	//printk("int served at %x\n",a);
	//ReadSector(0,0,1, buf, buf);
	//ReadRelativeSector(3, buf, buf);
	//printk("original sect 3 is\n");
	//for(a=0;a<8;a++)
	//   printk("%x ", buf[a]);
	//ReadRelativeSector(0, buf, buf);
	//printk("sect 0 is\n");
	//for(a=0;a<8;a++)
	//   printk("%x ", buf[a]);
	//WriteRelativeSector(3, buf, buf);
	//ReadRelativeSector(3, buf, buf);
	//printk("now. after write. sect 3 is\n");
	//for(a=0;a<8;a++)
	//   printk("%x ", buf[a]);
    /*
	printk("Hello from hos8\n");
	printk("systick = [%d]\n", systick);

	for(a = 0; a < 10000000; a++)
		;
	
	printk("systick = [%d]\n", systick);
	*/
	//for(;;);

    
	init_mm();
	make_init_task();
	current=init_task;


	//make_init_task();
	//current=init_task;

	//test_fs(); // test fs
	// enable paging
	printk("now enable paging\n");
	wait_for_anykey();
	pgdir_loc = init_task->mm.pgdir;
	__asm__ ("pushl %%eax\n\t"
	         "movl %0, %%eax\n\t"
		     "movl %%eax, %%cr3\n\t"
			 "movl %%cr0, %%eax\n\t"
			 "or $0x80000000, %%eax\n\t"
			 "movl %%eax, %%cr0\n\t"
			 "popl %%eax\n\t"
		     ::"m"(pgdir_loc));
    // force a jump to activate paging
	goto L1;
 L1:printk("paging enabled. are we still alive?\n");
	wait_for_anykey();
	printk("now init timer\n");
	init_timer(); 
	printk("aft init timer\n");
    
	// init fs needs timer.
	init_fs(); // init fs
	//now test exec
	kernel_thread(init);
	 
	//for(;;);

	// now move between p1 and p2
	// below thread experiment will be recovered later
	//kernel_thread(p1_body);
	//kernel_thread(p2_body);

	for(;;){
	   schedule();
		//printk("p0");
		//for(i=0;i<10000000;i++) b=b+1.0;
	}

}