void io_hlt(void);
void io_cli(void);
void io_out8(int port, int data);
int io_load_eflags(void);
void io_store_eflags(int eflags);

void init_palette(void);
void set_palette(int start, int end, unsigned char *rgb);
void boxfill8(unsigned char *vram, int xsize, unsigned char c, int x0, int y0, int x1, int y1);
void init_screen(char *vram, int x, int y);

#define COL8_000000		0
#define COL8_FF0000		1
#define COL8_00FF00		2
#define COL8_FFFF00		3
#define COL8_0000FF		4
#define COL8_FF00FF		5
#define COL8_00FFFF		6
#define COL8_FFFFFF		7
#define COL8_C6C6C6		8
#define COL8_840000		9
#define COL8_008400		10
#define COL8_848400		11
#define COL8_000084		12
#define COL8_840084		13
#define COL8_008484		14
#define COL8_848484		15

void HariMain(void)
{
	char *vram;/* 声明变量vram、用于BYTE [...]地址 */
	int xsize, ysize;
	short *binfo_scrnx, *binfo_scrny;
	int *binfo_vram;

	init_palette();
	binfo_scrnx = (short *) 0x0ff4;
	binfo_scrny = (short *) 0x0ff6;
	binfo_vram = (int *) 0x0ff8;
	xsize = *binfo_scrnx;
	ysize = *binfo_scrny;
	vram = (char *) *binfo_vram;

	init_screen(vram, xsize, ysize);

	for (;;) {
		io_hlt();
	}
}

void init_palette(void)
{
	static unsigned char table_rgb[16 * 3] = {
		0x00, 0x00, 0x00,	/*  0:黑 */
		0xff, 0x00, 0x00,	/*  1:梁红 */
		0x00, 0xff, 0x00,	/*  2:亮绿 */
		0xff, 0xff, 0x00,	/*  3:亮黄 */
		0x00, 0x00, 0xff,	/*  4:亮蓝 */
		0xff, 0x00, 0xff,	/*  5:亮紫 */
		0x00, 0xff, 0xff,	/*  6:浅亮蓝 */
		0xff, 0xff, 0xff,	/*  7:白 */
		0xc6, 0xc6, 0xc6,	/*  8:亮灰 */
		0x84, 0x00, 0x00,	/*  9:暗红 */
		0x00, 0x84, 0x00,	/* 10:暗绿 */
		0x84, 0x84, 0x00,	/* 11:暗黄 */
		0x00, 0x00, 0x84,	/* 12:暗青 */
		0x84, 0x00, 0x84,	/* 13:暗紫 */
		0x00, 0x84, 0x84,	/* 14:浅暗蓝 */
		0x84, 0x84, 0x84	/* 15:暗灰 */
	};
	set_palette(0, 15, table_rgb);
	return;

	/* C语言中的static char语句只能用于数据，相当于汇编中的DB指令 */
}

void set_palette(int start, int end, unsigned char *rgb)
{
	int i, eflags;
	eflags = io_load_eflags();	/* 记录中断许可标志的值 */
	io_cli(); 					/* 将中断许可标志置为0,禁止中断 */
	io_out8(0x03c8, start);
	for (i = start; i <= end; i++) {
		io_out8(0x03c9, rgb[0] / 4);
		io_out8(0x03c9, rgb[1] / 4);
		io_out8(0x03c9, rgb[2] / 4);
		rgb += 3;
	}
	io_store_eflags(eflags);	/* 复原中断许可标志 */
	return;
}

void boxfill8(unsigned char *vram, int xsize, unsigned char c, int x0, int y0, int x1, int y1)
{
	int x, y;
	for (y = y0; y <= y1; y++) {
		for (x = x0; x <= x1; x++)
			vram[y * xsize + x] = c;
	}
	return;
}

void init_screen(char *vram, int x, int y)
{
	boxfill8(vram, x, COL8_008484,  0,     0,      x -  1, y - 29);
	boxfill8(vram, x, COL8_C6C6C6,  0,     y - 28, x -  1, y - 28);
	boxfill8(vram, x, COL8_FFFFFF,  0,     y - 27, x -  1, y - 27);
	boxfill8(vram, x, COL8_C6C6C6,  0,     y - 26, x -  1, y -  1);

	boxfill8(vram, x, COL8_FFFFFF,  3,     y - 24, 59,     y - 24);
	boxfill8(vram, x, COL8_FFFFFF,  2,     y - 24,  2,     y -  4);
	boxfill8(vram, x, COL8_848484,  3,     y -  4, 59,     y -  4);
	boxfill8(vram, x, COL8_848484, 59,     y - 23, 59,     y -  5);
	boxfill8(vram, x, COL8_000000,  2,     y -  3, 59,     y -  3);
	boxfill8(vram, x, COL8_000000, 60,     y - 24, 60,     y -  3);

	boxfill8(vram, x, COL8_848484, x - 47, y - 24, x -  4, y - 24);
	boxfill8(vram, x, COL8_848484, x - 47, y - 23, x - 47, y -  4);
	boxfill8(vram, x, COL8_FFFFFF, x - 47, y -  3, x -  4, y -  3);
	boxfill8(vram, x, COL8_FFFFFF, x -  3, y - 24, x -  3, y -  3);
	return;
}
