1 保存启动信息
接受启动信息,我们以指针形式取得asmhead.nas中的信息保存,在系统出现故障时仍有余地还原。并且将初始化画面的代码封装为一个函数init_screen,便于维护,修改后的bootpack.c:
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;
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:黒 */
0xff, 0x00, 0x00, /* 1:明るい赤 */
0x00, 0xff, 0x00, /* 2:明るい緑 */
0xff, 0xff, 0x00, /* 3:明るい黄色 */
0x00, 0x00, 0xff, /* 4:明るい青 */
0xff, 0x00, 0xff, /* 5:明るい紫 */
0x00, 0xff, 0xff, /* 6:明るい水色 */
0xff, 0xff, 0xff, /* 7:白 */
0xc6, 0xc6, 0xc6, /* 8:明るい灰色 */
0x84, 0x00, 0x00, /* 9:暗い赤 */
0x00, 0x84, 0x00, /* 10:暗い緑 */
0x84, 0x84, 0x00, /* 11:暗い黄色 */
0x00, 0x00, 0x84, /* 12:暗い青 */
0x84, 0x00, 0x84, /* 13:暗い紫 */
0x00, 0x84, 0x84, /* 14:暗い水色 */
0x84, 0x84, 0x84 /* 15:暗い灰色 */
};
set_palette(0, 15, table_rgb);
return;
/* static char 命令,只能在数据上使用,但相当于DB命令 */
}
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(); /* 许可标志为0 */
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); /* 把中断许可标志还原 */
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;
}
2 使用结构体指针箭头符号
我们在HariMain()主函数中使用指针获取数据的形式看起来不是那么简洁,为此,我们可以尝试使用C中的结构体配合箭头符号使用,这样使我们的程序更加简洁:
struct BOOTINFO {
char cyls, leds, vmode, reserve;
short scrnx, scrny;
char *vram;
};
void HariMain(void)
{
struct BOOTINFO *binfo = (struct BOOTINFO *) 0x0ff0;
init_palette();
init_screen(binfo->vram, binfo->scrnx, binfo->scrny);
for (;;) {
io_hlt();
}
}
3 显示字符串
添加一个hankaku.txt文本文件,这个文本文件存放字符字体。使用makefont.exe读取到bootpack.c文件中用于显示字符串,为此需要设计一个用于显示字符,显示字符串的函数:
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);
void putfont8(char *vram, int xsize, int x, int y, char c, char *font);
void putfonts8_asc(char *vram, int xsize, int x, int y, char c, unsigned char *s);
#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
struct BOOTINFO {
char cyls, leds, vmode, reserve;
short scrnx, scrny;
char *vram;
};
void HariMain(void)
{
struct BOOTINFO *binfo = (struct BOOTINFO *) 0x0ff0;
init_palette();
init_screen(binfo->vram, binfo->scrnx, binfo->scrny);
putfonts8_asc(binfo->vram, binfo->scrnx, 8, 8, COL8_FFFFFF, "ABC 123");
putfonts8_asc(binfo->vram, binfo->scrnx, 31, 31, COL8_000000, "Haribote OS.");
putfonts8_asc(binfo->vram, binfo->scrnx, 30, 30, COL8_FFFFFF, "Haribote OS.");
for (;;) {
io_hlt();
}
}
void init_palette(void)
{
static unsigned char table_rgb[16 * 3] = {
0x00, 0x00, 0x00, /* 0:黒 */
0xff, 0x00, 0x00, /* 1:明るい赤 */
0x00, 0xff, 0x00, /* 2:明るい緑 */
0xff, 0xff, 0x00, /* 3:明るい黄色 */
0x00, 0x00, 0xff, /* 4:明るい青 */
0xff, 0x00, 0xff, /* 5:明るい紫 */
0x00, 0xff, 0xff, /* 6:明るい水色 */
0xff, 0xff, 0xff, /* 7:白 */
0xc6, 0xc6, 0xc6, /* 8:明るい灰色 */
0x84, 0x00, 0x00, /* 9:暗い赤 */
0x00, 0x84, 0x00, /* 10:暗い緑 */
0x84, 0x84, 0x00, /* 11:暗い黄色 */
0x00, 0x00, 0x84, /* 12:暗い青 */
0x84, 0x00, 0x84, /* 13:暗い紫 */
0x00, 0x84, 0x84, /* 14:暗い水色 */
0x84, 0x84, 0x84 /* 15:暗い灰色 */
};
set_palette(0, 15, table_rgb);
return;
/* static char 命令只在数据上使用,但相当于DB命令 */
}
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(); /* 许可标志为0 */
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); /* 把中断许可标志还原 */
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;
}
/*显示单个字符*/
void putfont8(char *vram, int xsize, int x, int y, char c, char *font)
{
int i;
char *p, d /* data */;
for (i = 0; i < 16; i++) {
p = vram + (y + i) * xsize + x;
d = font[i];
if ((d & 0x80) != 0) { p[0] = c; }
if ((d & 0x40) != 0) { p[1] = c; }
if ((d & 0x20) != 0) { p[2] = c; }
if ((d & 0x10) != 0) { p[3] = c; }
if ((d & 0x08) != 0) { p[4] = c; }
if ((d & 0x04) != 0) { p[5] = c; }
if ((d & 0x02) != 0) { p[6] = c; }
if ((d & 0x01) != 0) { p[7] = c; }
}
return;
}
/*显示字符串*/
void putfonts8_asc(char *vram, int xsize, int x, int y, char c, unsigned char *s)
{
extern char hankaku[4096];
for (; *s != 0x00; s++) {
putfont8(vram, xsize, x, y, c, hankaku + *s * 16);
x += 8;
}
return;
}
这样我们通过调用putfonts8_asc函数可以将字符串输出在背景中:
4 显示变量的值
要是我们能在背景中显示变量的值,这对于我们调试程序是有极大帮助的,C语言中的sprintf函数可以将内容作为字符串写入内存中,我们尝试一下:
sprintf(s, "scrnx = %d", binfo->scrnx);
在主函数中使用输出语句前记得先 #include <stdio.h>导入头文件,运行一下:
5 绘制鼠标图案
嗯,貌似缺少个可以移动的鼠标,刚开始我们的要求不需要那么高,先显示一个鼠标的图案,后续的开发我们再尝试让它移动起来吧,先添加一个鼠标初始化函数:
void init_mouse_cursor8(char *mouse, char bc)
/* 鼠标光标) */
{
static char cursor[16][16] = {
"**************..",
"*OOOOOOOOOOO*...",
"*OOOOOOOOOO*....",
"*OOOOOOOOO*.....",
"*OOOOOOOO*......",
"*OOOOOOO*.......",
"*OOOOOOO*.......",
"*OOOOOOOO*......",
"*OOOO**OOO*.....",
"*OOO*..*OOO*....",
"*OO*....*OOO*...",
"*O*......*OOO*..",
"**........*OOO*.",
"*..........*OOO*",
"............*OO*",
".............***"
};
int x, y;
for (y = 0; y < 16; y++) {
for (x = 0; x < 16; x++) {
if (cursor[y][x] == '*') {
mouse[y * 16 + x] = COL8_000000;
}
if (cursor[y][x] == 'O') {
mouse[y * 16 + x] = COL8_FFFFFF;
}
if (cursor[y][x] == '.') {
mouse[y * 16 + x] = bc;
}
}
}
return;
}
思路跟绘制字符大体差不多,绘制的时候控制下背景色,前景色即可。
主函数中尝试调用一下:
void HariMain(void)
{
struct BOOTINFO *binfo = (struct BOOTINFO *) 0x0ff0;
char s[40], mcursor[256];
int mx, my;
init_palette();
init_screen8(binfo->vram, binfo->scrnx, binfo->scrny);
mx = (binfo->scrnx - 16) / 2; /*以成为画面中央的坐标计算 */
my = (binfo->scrny - 28 - 16) / 2;
init_mouse_cursor8(mcursor, COL8_008484);/*初始化鼠标光标*/
putblock8_8(binfo->vram, binfo->scrnx, 16, 16, mx, my, mcursor, 16);
sprintf(s, "(%d, %d)", mx, my);
putfonts8_asc(binfo->vram, binfo->scrnx, 0, 0, COL8_FFFFFF, s);
for (;;) {
io_hlt();
}
}
运行结果:
今天的内容大概笔者就学了这么多,还有部分难以理解的就没有深入学习,精力时间有限。