不知道这样算不算保护模式下的图形模式

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我是靠谱客的博主机智服饰，最近开发中收集的这篇文章主要介绍不知道这样算不算保护模式下的图形模式，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

百度网盘下载地址：

https://pan.baidu.com/s/1_-IznMWL3z1CROziiD6mCw

好了先是晒图吧

这里只晒代码了，编译方法和环境搭建过程还是请参考我之前的文章好了，不过觉得自己还真的是切换到了图形模式，只是不懂得怎样调色，还请高手回复帮忙吧(有很多的代码是没有用到的，只是懒得删除罢了！kernel.c就只是从https://www.gnu.org/software/grub/manual/multiboot2/multiboot.html#Examples粘贴过来的，蓝色的部分真正的改正过，也是关键的部分，其余大家可以不看)。multiboot2.h从网站上下载。

boot.s

.extern _kernel_main, _string
.global _put_char

_start:

jmp _begin
.align 8

header_start:
   .int 0xe85250d6
   .int 0x0
   .int header_end - header_start
   .int -(0xe85250d6 + 0x0 + (header_end - header_start))

add_tag_start:
   .word 0x2
   .word 0x0
   .int add_tag_end - add_tag_start
   .int header_start
   .int _start
   .int 0x0
   .int 0x0
add_tag_end:

entry_add_tag_start:
   .word 0x3
   .word 0x1
   .int entry_add_tag_end - entry_add_tag_start
   .int _begin
entry_add_tag_end:
.align 8

framebuffer_tag_start:
.short 0x5
.short 0x1
.long framebuffer_tag_end - framebuffer_tag_start
.long 1024
.long 768
.long 32
framebuffer_tag_end:
.align 8

   .word 0x0
   .word 0
   .int 8
header_end:

.align 8

_begin:

   mov $stack_start, %esp
   pushl $0
   popf
   cli

   push %ebx
   push %eax
   call _kernel_main
2:
   hlt
   jmp 2b

.align 8
_put_char: # void print (char str);

   push %es
   push %eax
   push %esi
   mov $0x18, %eax
   mov %eax, %es
   mov (_scr_loc), %esi
   mov 0x10(%esp), %al
   mov $0xc, %ah
   movw %ax, %es: (%esi)
   inc %esi
   inc %esi
   cmp $2000, %esi
   jne next0
   xor %esi, %esi
next0:
   mov %esi, (_scr_loc)
   pop %esi
   pop %eax
   pop %es

ret

idtr:
   .word 0
   .int 0
gdtr:
   .word 4 * 8 - 1
   .int gdt_start

.align 8

gdt_start:
   .quad 0x0000000000000000
   .quad 0x00c09a100000ffff
   .quad 0x00c092000000ffff
   .quad 0x00c0920b80000002


gdt_end:

.align 8

_position: .int 0;
_scr_loc: .int 0;

.comm stack, 0x100
.align (4 << 10)
stack_start:

kernel.c

#include "multiboot2.h"

#define COLUMNS 80
#define LINES 24
#define ATTRIBUTE 7
#define VIDEO 0xB8000

static int xpos;
static int ypos;
static volatile unsigned char *video;

int kernel_main (unsigned int magic, unsigned int addr) ;
static void cls (void);
static void itoa (char *buf, int base, int d);
static void putchar (int c);
void printf (const char *format, ...);

int scr_loc = 0;

char string[10];

extern void put_char(char str);
int kernel_main (unsigned int magic, unsigned int addr) {
struct multiboot_tag *tag;
unsigned size;

/* Clear the screen. */
cls ();

/* Am I booted by a Multiboot-compliant boot loader? */
if (magic != MULTIBOOT2_BOOTLOADER_MAGIC)
{
printf ("Invalid magic number: 0x%xn", (unsigned) magic);

}

if (addr & 7)
{
printf ("Unaligned mbi: 0x%xn", addr);

}

size = *(unsigned *) addr;
printf ("Announced mbi size 0x%xn", size);
for (tag = (struct multiboot_tag *) (addr + 8);
tag->type != MULTIBOOT_TAG_TYPE_END;
tag = (struct multiboot_tag *) ((multiboot_uint8_t *) tag
+ ((tag->size + 7) & ~7)))
{
printf ("Tag 0x%x, Size 0x%xn", tag->type, tag->size);
switch (tag->type)
{
case MULTIBOOT_TAG_TYPE_CMDLINE:
printf ("Command line = %sn",
((struct multiboot_tag_string *) tag)->string);
break;
case MULTIBOOT_TAG_TYPE_BOOT_LOADER_NAME:
printf ("Boot loader name = %sn",
((struct multiboot_tag_string *) tag)->string);
break;
case MULTIBOOT_TAG_TYPE_MODULE:
printf ("Module at 0x%x-0x%x. Command line %sn",
((struct multiboot_tag_module *) tag)->mod_start,
((struct multiboot_tag_module *) tag)->mod_end,
((struct multiboot_tag_module *) tag)->cmdline);
break;
case MULTIBOOT_TAG_TYPE_BASIC_MEMINFO:
printf ("mem_lower = %uKB, mem_upper = %uKBn",
((struct multiboot_tag_basic_meminfo *) tag)->mem_lower,
((struct multiboot_tag_basic_meminfo *) tag)->mem_upper);
break;
case MULTIBOOT_TAG_TYPE_BOOTDEV:
printf ("Boot device 0x%x,%u,%un",
((struct multiboot_tag_bootdev *) tag)->biosdev,
((struct multiboot_tag_bootdev *) tag)->slice,
((struct multiboot_tag_bootdev *) tag)->part);
break;
case MULTIBOOT_TAG_TYPE_MMAP:
{
multiboot_memory_map_t *mmap;

printf ("mmapn");

for (mmap = ((struct multiboot_tag_mmap *) tag)->entries;
(multiboot_uint8_t *) mmap
< (multiboot_uint8_t *) tag + tag->size;
mmap = (multiboot_memory_map_t *)
((unsigned long) mmap
+ ((struct multiboot_tag_mmap *) tag)->entry_size))
printf (" base_addr = 0x%x%x,"
" length = 0x%x%x, type = 0x%xn",
(unsigned) (mmap->addr >> 32),
(unsigned) (mmap->addr & 0xffffffff),
(unsigned) (mmap->len >> 32),
(unsigned) (mmap->len & 0xffffffff),
(unsigned) mmap->type);
}
break;
case MULTIBOOT_TAG_TYPE_FRAMEBUFFER:
{
multiboot_uint32_t color;
unsigned i;
struct multiboot_tag_framebuffer *tagfb
= (struct multiboot_tag_framebuffer *) tag;
void *fb = (void *) (unsigned long) tagfb->common.framebuffer_addr;

switch (tagfb->common.framebuffer_type)
{
case MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED:
{
unsigned best_distance, distance;
struct multiboot_color *palette;

palette = tagfb->framebuffer_palette;

color = 0;
best_distance = 4*256*256;

for (i = 0; i < tagfb->framebuffer_palette_num_colors; i++)
{
distance = (0xff - palette[i].blue)
* (0xff - palette[i].blue)
+ palette[i].red * palette[i].red
+ palette[i].green * palette[i].green;
if (distance < best_distance)
{
color = i;
best_distance = distance;
}
}
}
break;

case MULTIBOOT_FRAMEBUFFER_TYPE_RGB:
color = ((1 << tagfb->framebuffer_blue_mask_size) - 1)
<< tagfb->framebuffer_blue_field_position;
break;

case MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT:
color = '\' | 0x0100;
break;

default:
color = 0xffffffff;
break;
}

for (i = 0; i < tagfb->common.framebuffer_width
&& i < tagfb->common.framebuffer_height; i++)
{

                   switch (tagfb->common.framebuffer_bpp)
{
case 8:
{
multiboot_uint8_t *pixel = fb
+ tagfb->common.framebuffer_pitch * i + i;
*pixel = color;
}
break;
case 15:
case 16:
{
multiboot_uint16_t *pixel
= fb + tagfb->common.framebuffer_pitch * i + 2 * i;
*pixel = color;
}
break;
case 24:
{
multiboot_uint32_t *pixel
= fb + tagfb->common.framebuffer_pitch * i + 3 * i;
*pixel = (color & 0xffffff) | (*pixel & 0xff000000);
}
break;

case 32:
{
multiboot_uint32_t *pixel
= fb + tagfb->common.framebuffer_pitch * i;
                           for (int j= 0; j < 800; j++)
*(pixel + j) = color;

}
                       break;
}
}

break;
}

}
}
tag = (struct multiboot_tag *) ((multiboot_uint8_t *) tag
+ ((tag->size + 7) & ~7));
printf ("Total mbi size 0x%xn", (unsigned) tag - addr);
   int aaa = 5678;
   printf("My name is Zhi Qiang Li, %d", aaa);

return 1;
}

static void
cls (void)
{
int i;

video = (unsigned char *) VIDEO;

for (i = 0; i < COLUMNS * LINES * 2; i++)
*(video + i) = 0;

xpos = 0;
ypos = 0;
}

/* Convert the integer D to a string and save the string in BUF. If
BASE is equal to 'd', interpret that D is decimal, and if BASE is
equal to 'x', interpret that D is hexadecimal. */
static void
itoa (char *buf, int base, int d)
{
char *p = buf;
char *p1, *p2;
unsigned long ud = d;
int divisor = 10;

/* If %d is specified and D is minus, put `-' in the head. */
if (base == 'd' && d < 0)
{
*p++ = '-';
buf++;
ud = -d;
}
else if (base == 'x')
divisor = 16;

/* Divide UD by DIVISOR until UD == 0. */
do
{
int remainder = ud % divisor;

*p++ = (remainder < 10) ? remainder + '0' : remainder + 'a' - 10;
}
while (ud /= divisor);

/* Terminate BUF. */
*p = 0;

/* Reverse BUF. */
p1 = buf;
p2 = p - 1;
while (p1 < p2)
{
char tmp = *p1;
*p1 = *p2;
*p2 = tmp;
p1++;
p2--;
}
}

/* Put the character C on the screen. */
static void
putchar (int c)
{
if (c == 'n' || c == 'r')
{
newline:
xpos = 0;
ypos++;
if (ypos >= LINES)
ypos = 0;
return;
}

*(video + (xpos + ypos * COLUMNS) * 2) = c & 0xFF;
*(video + (xpos + ypos * COLUMNS) * 2 + 1) = ATTRIBUTE;

xpos++;
if (xpos >= COLUMNS)
goto newline;
}

/* Format a string and print it on the screen, just like the libc
function printf. */
void
printf (const char *format, ...)
{
char **arg = (char **) &format;
int c;
char buf[20];

arg++;

while ((c = *format++) != 0)
{
if (c != '%')
putchar (c);
else
{
char *p, *p2;
int pad0 = 0, pad = 0;

c = *format++;
if (c == '0')
{
pad0 = 1;
c = *format++;
}

if (c >= '0' && c <= '9')
{
pad = c - '0';
c = *format++;
}

switch (c)
{
case 'd':
case 'u':
case 'x':
itoa (buf, c, *((int *) arg++));
p = buf;
goto string;
break;

case 's':
p = *arg++;
if (! p)
p = "(null)";

string:
for (p2 = p; *p2; p2++);
for (; p2 < p + pad; p2++)
putchar (pad0 ? '0' : ' ');
while (*p)
putchar (*p++);
break;

default:
putchar (*((int *) arg++));
break;
}
}
}
}