kern/kernel.c

//a.michelizza.free.fr
#define mysect 2880

#define nbrSectorsToRead 10//1*2048 //*512 pour obtenir le nombre d'octets.
#include "types.h"
#include "gdt.h"
#include "io.h"

void findString(char *addr,char *str);
void printHexa(unsigned int dec,int nbrDigit);
int bl_read(int drive, int numblock, int count, char *buf);
void _start(void)
{
    //check is A20 is OK
        init_gdt();
        asm("   movw $0x18, %ax \n \
                movw %ax, %ss \n \
                movl $0x1fffffff, %esp");

        asm volatile("mov %0,(0x00200000)\n\t"::"a"(printHexa));

    bl_read(0, mysect, nbrSectorsToRead, (char*)0x00400200);//512i
    findString((char *)0x00400200,"\n=BEGIN TRUE CODE=\n");

        asm volatile("jmp 0x00400200\n\t");
}
void findString(char *addr,char *str)
{
    char *addrb;
    char *strb;
    while(1)
    {
        if(*addr == *str)
        {
            addrb=addr;
            strb=str;
            while(*addrb == *strb || *strb == 0)
            {
                if(*strb == 0)
                {
                    asm volatile("movl %0,(0x10000000)"::"a"(addr));
                    return;
                }
                addrb++;
                strb++;
            }
        }

        addr++;
    }
}
void printHexa(unsigned int dec,int nbrDigit)
{
        return;
}
int bl_read(int drive, int numblock, int count, char *buf)
{

        u16 tmpword;
        int idx;

        outb(0x1F1, 0x00);      /* NULL byte to port 0x1F1 */
        outb(0x1F2, (unsigned char)count);      /* Sector count */
        outb(0x1F3, (unsigned char) numblock);  /* Low 8 bits of the block address */
        outb(0x1F4, (unsigned char) (numblock >> 8));   /* Next 8 bits of the block address */
        outb(0x1F5, (unsigned char) (numblock >> 16));  /* Next 8 bits of the block address */

        /* Drive indicator, magic bits, and highest 4 bits of the block address */
        outb(0x1F6, 0xE0 | (drive << 4) | ((numblock >> 24) & 0x0F));
        outb(0x1F7, 0x20);

        /* Wait for the drive to signal that it's ready: */
        while (!(inb(0x1F7) & 0x08));

        for (idx = 0; idx < 256 * count; idx++) {
                tmpword = inw(0x1F0);
                buf[idx * 2] = (unsigned char) tmpword;
                buf[idx * 2 + 1] = (unsigned char) (tmpword >> 8);
        }
        return count;
}