linux操作系统学习实践 －－－e820.c

/* e820_map.c
 *I don't mean to write the whole OS kernel.I just want to put what I have
 *already learned into practice.But what will it be end up looking like.
 *I don't know.ALA I have some free time,I will write something.Just like
 *linus once said,"Just for fun".I don't care what this small ugly codes
 *will be capable of,or does it worth something.I just write it for fun,
 *and for practice.

 *         10 / 12 / 2010        liangtao
 *            E-mail:[e-mail]
 */
/* used only for test currently */
#include
#include
#include

struct e820_map e820_map_table[E820_MAP_NR_MAX];
unsigned short e820_map_nr;

void setup_e820_map(void)
{
    int i = 0;
    e820_map_nr = *(unsigned short *)((E820_MAP_SEG << 4) + E820_MAP_NR);
    struct e820_map *base = (struct e820_map *)E820_MAP_BASE;
    if(e820_map_nr > E820_MAP_NR_MAX) {
        printf("!!!!!!BUG!!!!!!got %hd e820 map!!!!!!!!\n", e820_map_nr);
        while(1);
    }
    while(i < e820_map_nr ) {
        memncpy((void *)(e820_map_table + i),(base + i), 20);
        i++;
    }
}

static void end(void)
{
    int i = 1;
    while(i--);
}

void show_mem_info(void)
{
    int i;
    unsigned char e801_flag = *(unsigned char *)((E820_MAP_SEG << 4) + E801_FLAG);
    unsigned char mem88_flag = *(unsigned char *)((E820_MAP_SEG << 4) + MEM88_FLAG);
    struct e820_map *map_base = e820_map_table + 0;
    putstr("!!!!memory map info got from e820 bios call:\n");
    for(i = 0; i < e820_map_nr; i++) {
        printf("map %dth:\t\n", i);
        printf("\tbase addr low32 :\t %#x\n", map_base->base_addr_low32);
        printf("\tbase addr high32 :\t %#x\n", map_base->base_addr_high32);
        printf("\tlength low32 :\t %#x\n", map_base->len_low32);
        printf("\tlength high32 :\t %#x\n", map_base->len_high32);
        if(map_base->type == E820_TYPE_AVAIL)
            putstr("\tthis memory region is available and can be used by the OS!\n");
        else if(map_base->type == E820_TYPE_RESERVED)
            putstr("\tthis memory region is reserved and cannot be used by the OS!\n");
        else if(map_base->type == E820_TYPE_UNDEF)
            putstr("\tthis memory region is undefined and cannot be used by the OS!\n");
        else
            putstr("!!!!!!!!!!!UNKNOW MEMORY REGION TYPE!!!!!!!!!!!!!!\n");
        map_base++;
        end();
    }
    if(e801_flag == 1) {
        unsigned long e801_part1 = *(unsigned long *)((E820_MAP_SEG << 4) + E801_PART1);
        unsigned long e801_part2 = *(unsigned long *)((E820_MAP_SEG << 4) + E801_PART2);
        e801_part2 <<= 6;
        printf("E801 way. EXT 1 is:\t %ld KB\n", e801_part1);
        printf("E801 way. EXT 2 is:\t %ld KB\n", e801_part2);
    }
    else
        putstr("!!!!!!!e801 way failed!\n");
    if(mem88_flag != 0) {
        unsigned short mem_88 = *(unsigned long *)((E820_MAP_SEG << 4) + MEM88_EXT);
        printf("88 way. EXT     is:\t %hd KB\n", mem_88);
    }
}