/* DSTAT : Disk Stat: the Whole Shebang
 * Wilson H. Bent, Jr. : RCP/M: Lillipute: (312) 649-1730 Chicago
 * Version 0.1 : Last Mod 06/02/86
 *
 * A Thorough Dump of the Disk Parameters as known by the BIOS.
 * Written for Aztec C : uses functions bioshl() and bdos()
 */

/* BDOS Defines */
#define SELDISK	14
#define CRNTDSK	25

/* BIOS Defines */
#define SELDSK	9

/* The structure member names are those used in
 * the CP/M 2.2 Operating System Manual
 */
/* Disk Parameter Header */
struct dph {
	char		*xlt;	/* Logical-Physical Translation pointer */
	int		 xxx[3];/* (used by BDOS) */
	char		*dbuf;	/* Directory Buffer pointer */
	struct dpb	*dpb;	/* Disk Parameter Block pointer */
	int		*csv;	/* Scratch Pad pointer */
	int		*alv;	/* Allocation Vector pointer */
} *dphp;

/* Disk Parameter Block */
struct dpb {
	int	spt;		/* Sectors per Track */
	char	bsh;		/* Block Shift */
	char	blm;		/* Block Mask */
	char	exm;		/* Extent Mask */
	int	dsm;		/* Max. Block Number */
	int	drm;		/* No. of Dir Entries - 1 */
	char	al0, al1;	/* Dir Block Bitmap */
	int	cks;		/* Dir Check Vector Size */
	int	off;		/* Reserved Tracks Offset */
} *dpbp;

int		currdisk;	/* Current Disk */
int		seldisk;	/* Selected Disk */
unsigned int	bls;		/* Block Size */
long		dcap;		/* Disk Capacity */

main (argc, argv)
char *argv[];
{
	register int i;

	/* preserve the current disk */
	currdisk = bdos (CRNTDSK, 0);

	/* get the argument disk, if one is asked for */
	if (argc > 1)
		seldisk = *argv[1] - 'A';

	/* ..otherwise, use the current disk */
	else
		seldisk = currdisk;

	/* use the BIOS call to get a pointer to the DPH */
	dphp = bioshl (SELDSK, seldisk, 0);
	printf ("Disk %c:\n  DPH: 0%04x\n", seldisk + 'A', dphp);
	if (dphp == 0) {
		printf ("No such disk!\n");
		goto away;
	}

	/* The DPH Stats! */
	printf ("Log-Phys Trans:\t0%04x\n", dphp -> xlt);
	printf ("Dir Buff:\t0%04x\n", dphp -> dbuf);
	printf ("Scratch Pad:\t0%04x\n", dphp -> csv);
	printf ("Alloc Vector:\t0%04x\n", dphp -> alv);

	/* the DPH has the pointer to the DPB */
	dpbp = dphp -> dpb;

	/* The DPB Stats! */
	printf ("\n  DPB Addr: 0%04x\n", dpbp);
	printf ("Sect per Track:\t%5d\n", dpbp -> spt);
	printf ("Block Shift:\t   %2d\n", (int)dpbp -> bsh);
	printf ("Block Mask:\t   %2d\n", (int)dpbp -> blm);
	printf ("Extent Mask:\t   %2d\n", (int)dpbp -> exm);

	/* Block Size is a computed value, not in the DPB */
	for (i = dpbp -> bsh, bls = 1; i > 0; --i)
		bls <<= 1;
	bls *= 0x80;
	printf ("Block Size: %u bytes\n", bls);

	/* the Disk Capacity is also a computed value */
	printf ("Max Block:\t %4xh\n", dpbp -> dsm + 1);
	dcap = (long) bls * (long) (dpbp -> dsm + 1);
	printf ("DISK CAPACITY (incl. Directory): %ld (0%lx) Bytes\n",
		dcap, dcap);

	printf ("Dir Entries:\t%5d\n", dpbp -> drm);
	printf ("Dir Bitmap:  ");
	pbits (dpbp -> al0, 8);
	pbits (dpbp -> al1, 8);
	putchar ('\n');
	printf ("DSV Size:\t%5d\n", dpbp -> cks);
	printf ("Sys Tracks:\t%5d\n", dpbp -> off);

	/* back to the proper disk! */
away:
	bdos (SELDISK, currdisk);
}

/* print NUM in binary, which is of size BITS */
pbits(num,bits)
	int num;
	int bits;
{
	unsigned mask;
	for (mask = 1 << (bits - 1); mask; mask >>= 1)
		putchar ((num & mask) ? '1' : '0');
}