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multiboot2
grub/doc/kernel.c
T
Vladimir 'phcoder' Serbinenko c841decd4d Merge multiboot2 into mbtag-spec
2010-03-28 13:59:16 +02:00

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/* kernel.c - the C part of the kernel */
/* Copyright (C) 1999, 2010 Free Software Foundation, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "multiboot2.h"
/* Macros. */
/* Some screen stuff. */
/* The number of columns. */
#define COLUMNS 80
/* The number of lines. */
#define LINES 24
/* The attribute of an character. */
#define ATTRIBUTE 7
/* The video memory address. */
#define VIDEO 0xB8000
/* Variables. */
/* Save the X position. */
static int xpos;
/* Save the Y position. */
static int ypos;
/* Point to the video memory. */
static volatile unsigned char *video;
/* Forward declarations. */
void cmain (unsigned long magic, unsigned long addr);
static void cls (void);
static void itoa (char *buf, int base, int d);
static void putchar (int c);
void printf (const char *format, ...);
/* Check if MAGIC is valid and print the Multiboot information structure
pointed by ADDR. */
void
cmain (unsigned long magic, unsigned long 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%x\n", (unsigned) magic);
return;
}
if (addr & 7)
{
printf ("Unaligned mbi: 0x%x\n", addr);
return;
}
size = *(unsigned *) addr;
printf ("Announced mbi size 0x%x\n", 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%x\n", tag->type, tag->size);
switch (tag->type)
{
case MULTIBOOT_TAG_TYPE_CMDLINE:
printf ("Command line = %s\n",
((struct multiboot_tag_string *) tag)->string);
break;
case MULTIBOOT_TAG_TYPE_BOOT_LOADER_NAME:
printf ("Boot loader name = %s\n",
((struct multiboot_tag_string *) tag)->string);
break;
case MULTIBOOT_TAG_TYPE_MODULE:
printf ("Module at 0x%x-0x%x. Command line %s\n",
((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 = %uKB\n",
((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,%u\n",
((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 ("mmap\n");
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%x\n",
(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 + 4 * i;
*pixel = color;
}
break;
}
}
break;
}
}
}
tag = (struct multiboot_tag *) ((multiboot_uint8_t *) tag
+ ((tag->size + 7) & ~7));
printf ("Total mbi size 0x%x\n", (unsigned) tag - addr);
}
/* Clear the screen and initialize VIDEO, XPOS and YPOS. */
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;
}
}
}
}
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