main.c

这是《自己动手写操作系统》的原文件和代码

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                            main.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                                                    Forrest Yu, 2005
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

#include "type.h"
#include "const.h"
#include "protect.h"
#include "string.h"
#include "proc.h"
#include "tty.h"
#include "console.h"
#include "global.h"
#include "proto.h"


/*======================================================================*
                            tinix_main
 *======================================================================*/
PUBLIC int tinix_main()
{
	disp_str("-----\"tinix_main\" begins-----\n");

	TASK*		p_task;
	PROCESS*	p_proc		= proc_table;
	char*		p_task_stack	= task_stack + STACK_SIZE_TOTAL;
	t_16		selector_ldt	= SELECTOR_LDT_FIRST;
	int		i;
	t_8		privilege;
	t_8		rpl;
	int		eflags;
	for(i=0;i<NR_TASKS+NR_PROCS;i++){
		if (i < NR_TASKS) {	/* 任务 */
			p_task		= task_table + i;
			privilege	= PRIVILEGE_TASK;
			rpl		= RPL_TASK;
			eflags		= 0x1202;	/* IF=1, IOPL=1, bit 2 is always 1 */
		}
		else {			/* 用户进程 */
			p_task		= user_proc_table + (i - NR_TASKS);
			privilege	= PRIVILEGE_USER;
			rpl		= RPL_USER;
			eflags		= 0x202;	/* IF=1, bit 2 is always 1 */
		}

		strcpy(p_proc->name, p_task->name);	/* name of the process */
		p_proc->pid	= i;			/* pid */

		p_proc->ldt_sel	= selector_ldt;
		memcpy(&p_proc->ldts[0], &gdt[SELECTOR_KERNEL_CS >> 3], sizeof(DESCRIPTOR));
		p_proc->ldts[0].attr1 = DA_C | privilege << 5;	/* change the DPL */
		memcpy(&p_proc->ldts[1], &gdt[SELECTOR_KERNEL_DS >> 3], sizeof(DESCRIPTOR));
		p_proc->ldts[1].attr1 = DA_DRW | privilege << 5;/* change the DPL */
		p_proc->regs.cs		= ((8 * 0) & SA_RPL_MASK & SA_TI_MASK) | SA_TIL | rpl;
		p_proc->regs.ds		= ((8 * 1) & SA_RPL_MASK & SA_TI_MASK) | SA_TIL | rpl;
		p_proc->regs.es		= ((8 * 1) & SA_RPL_MASK & SA_TI_MASK) | SA_TIL | rpl;
		p_proc->regs.fs		= ((8 * 1) & SA_RPL_MASK & SA_TI_MASK) | SA_TIL | rpl;
		p_proc->regs.ss		= ((8 * 1) & SA_RPL_MASK & SA_TI_MASK) | SA_TIL | rpl;
		p_proc->regs.gs		= (SELECTOR_KERNEL_GS & SA_RPL_MASK) | rpl;
		p_proc->regs.eip	= (t_32)p_task->initial_eip;
		p_proc->regs.esp	= (t_32)p_task_stack;
		p_proc->regs.eflags	= eflags;

		p_task_stack -= p_task->stacksize;
		p_proc++;
		p_task++;
		selector_ldt += 1 << 3;
	}
	proc_table[0].ticks = proc_table[0].priority = 15;
	proc_table[1].ticks = proc_table[1].priority =  5;
	proc_table[2].ticks = proc_table[2].priority =  5;
	proc_table[3].ticks = proc_table[3].priority =  5;

	k_reenter	= 0;
	ticks		= 0;

	p_proc_ready	= proc_table;
	
	init_clock();

	restart();

	while(1){}
}

/*======================================================================*
                               TestA
 *======================================================================*/
void TestA()
{
	while(1){
		milli_delay(10);
	}
}


/*======================================================================*
                               TestB
 *======================================================================*/
void TestB()
{
	int i = 0;
	while(1){
		milli_delay(10);
	}
}


/*======================================================================*
                               TestC
 *======================================================================*/
void TestC()
{
	int i = 0;
	while(1){
		milli_delay(10);
	}
}