good_rk.c

来自「unix v7是最后一个广泛发布的研究型UNIX版本」· C语言 代码 · 共 62 行

/*
 * RK disk driver
 */

#include <sys/param.h>
#include <sys/inode.h>
#include "saio.h"

#define	RKADDR	((struct device *)0177400)
#define	NRK	4
#define	NRKBLK	4872

#define	RESET	0
#define	WCOM	2
#define	RCOM	4
#define	GO	01
#define	DRESET	014
#define	IENABLE	0100
#define	DRY	0200
#define	ARDY	0100
#define	WLO	020000
#define	CTLRDY	0200

struct	device
{
	int	rkds;
	int	rker;
	int	rkcs;
	int	rkwc;
	caddr_t	rkba;
	int	rkda;
};

rkstrategy(io, func)
register struct iob *io;
{
	register com;
	daddr_t bn;
	int dn, cn, sn;

	bn = io->i_bn;
	dn = io->i_unit;
	cn = bn/12;
	sn = bn%12;
	RKADDR->rkda = (dn<<13) | (cn<<4) | sn;
	RKADDR->rkba = io->i_ma;
	RKADDR->rkwc = -(io->i_cc>>1);
	com = (segflag<<4)|GO;
	if (func == READ)
		com |= RCOM; else
		com |= WCOM;
	RKADDR->rkcs = com;
	while ((RKADDR->rkcs&CTLRDY) == 0)
		;
	if (RKADDR->rkcs<0) {	/* error bit */
		printf("disk error: cyl=%d, sector=%d, er=%o, ds=%o\n",
		    cn, sn, RKADDR->rker, RKADDR->rkds);
		return(-1);
	}
	return(io->i_cc);
}