CeDOS - boot/main.c

boot/main.c (view raw)

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#include <stdint.h>

#include "string.h"
#include "fat.h"

void printc(char c) {
    static uint8_t *display = (uint8_t*)(0xB8000);
    *(display++) = c;
    *(display++) = 0x0F;
}

void print_string(char *str) {
    while (*str != 0) {
        printc(*(str++));
    }
}

int load_kernel() {
    // debug output
    uint8_t *dbuf = (uint8_t *)(0x10000);
    for (int i = 0; i < 16; i++) {
        uint8_t value = dbuf[i];
        char lut[] = "0123456789ABCDEF";

        uint8_t low = value & 0x0F;
        uint8_t high = value >> 4;

        printc(lut[high]);
        printc(lut[low]);
        printc(' ');
    }

    //while (1);

    FAT_init();

    int i = 0;

    // first cluster of kernel.bin file
    uint16_t first_cluster;

    while (1) {
        char buffer[832];
        uint32_t file_size;

        i = FAT_root_dir_next(i, buffer, &first_cluster, &file_size);

        print_string(buffer);
        print_string("  ");
        if (i <= 0) { return -1; }

        if (!(strcmp(buffer, "kernel.bin"))) { break; }
    }

    // copy all clusters
    uint16_t cluster = first_cluster;
    uint8_t *buffer = (uint8_t *)(0x100000);
    while (1) {
        buffer = FAT_read_cluster(cluster, buffer);
        cluster = FAT_next_cluster(cluster);
        
        if (cluster == 0xFFF || cluster == 0x000) { break; }
    }

    return 0;
}