df.c

Linux0.01设备驱动程序 最精简的linux代码 适合操作系统入门

/* df.c */
#include <stdio.h>
#include <pc.h>

void detect_floppy_drives()
{
    unsigned char c;
    unsigned char a, b;
    char drive_type[][50] = {
                                "no floppy drive",
                                "360kb 5.25in floppy drive",
                                "1.2mb 5.25in floppy drive",
                                "720kb 3.5in",
                                "1.44mb 3.5in",
                                "2.88mb 3.5in" };

    outportb(0x70, 0x10);
    c = inportb(0x71);

    a = c >> 4;		// get the high nibble
    b = c & 0xF;	// get the low nibble by ANDing out the high nibble

    printf("Floppy drive A is an:\n");
    printf(drive_type[a]);
    printf("\nFloppy drive B is an:\n");
    printf(drive_type[b]);
    printf("\n");
};

int main()
{
    detect_floppy_drives();

    return 0;
}