#include "boot.h"

int (*sread)() = 0;

extern fail();

boot ()
	{
	struct block0 d;
	register c, s, h, n;
	char *a;
	int (*f)();


	init ();

/*
 * read block 0
 */

	d.ncyl = d.nhead = d.nsect = 1;

	if ((*sread) (0, 0, 0, &d))
		fail ();

	n = d.bootcount;
	c = d.bootcyl;
	s = d.bootsect;
	h = d.boothead;
	a = LOADADDR;

	while (n--)
		{
		if ((*sread) (c, h, s, a))
			fail ();

		a += d.bps;
		
		if (++s >= d.nsect)
			{
			s = 0;	/* new head */

			if (++h >= d.nhead)
				{
				h = 0;	/* new cylinder */

				if (++c >= d.ncyl)
					{
					c = 0;	/* wrap around */
					}
				}
			}
		}

/*
 * Loading completed
 * Jump into code.
 */

	f = LOADADDR;
	(*f)();
	}

/*
 * init - initialization
 *
 *	Init must set sread to either djread or mwread
 * 	Don't worry about the serial I/O, it will be set for us.
 */

init ()
	{
	if (floppy ())
		sread = djread;
	else
		sread = mwread;
	}

floppy ()
	{
	char c;

	if (djopen () < 0)
		return NO;

	prs ("Boot from the floppy?");

	c = getchar ();
	putchar (c);		/* echo */

	c = tolower (c);
	}

tolower (c)
	char c;
	{
	if ('A' <= c && c <= 'Z')
		c += ('a' - 'A');

	return c;
	}