/*	$NetBSD: mips_param.h,v 1.10 1998/09/11 16:46:31 jonathan Exp $	*/

/*
 * Architecture name.
 */
#define	_MACHINE_ARCH	mips
#define	MACHINE_ARCH	"mips"

/*
 * NOTE: SSIZE, SINCR and UPAGES must be multiples of CLSIZE.
 * On mips, UPAGES is fixed by sys/arch/mips/mips/locore code
 * to be the number of per-process-wired kernel-stack pages/PTES.
 */

#define	SSIZE		1		/* initial stack size/NBPG */
#define	SINCR		1		/* increment of stack/NBPG */

#define	UPAGES		2		/* pages of u-area */
#define	UADDR		0xffffc000	/* address of u */
#define USPACE          (UPAGES*NBPG)   /* size of u-area in bytes */
#define	UVPN		(UADDR>>PGSHIFT)/* virtual page number of u */
#define	KERNELSTACK	(UADDR+UPAGES*NBPG)	/* top of kernel stack */

#ifndef MSGBUFSIZE
#define MSGBUFSIZE	NBPG		/* default message buffer size */
#endif

/*
 * Round p (pointer or byte index) up to a correctly-aligned value for all
 * data types (int, long, ...).   The result is u_int and must be cast to
 * any desired pointer type.
 *
 * ALIGNED_POINTER is a boolean macro that checks whether an address
 * is valid to fetch data elements of type t from on this architecture.
 * This does not reflect the optimal alignment, just the possibility
 * (within reasonable limits). 
 *
 */
#define	ALIGNBYTES	7
#define	ALIGN(p)	(((u_int)(p) + ALIGNBYTES) & ~ALIGNBYTES)
#define ALIGNED_POINTER(p,t)	((((u_long)(p)) & (sizeof(t)-1)) == 0)

#define	NBPG		4096		/* bytes/page */
#define	PGOFSET		(NBPG-1)	/* byte offset into page */
#define	PGSHIFT		12		/* LOG2(NBPG) */
#define	NPTEPG		(NBPG/4)

#define NBSEG		0x400000	/* bytes/segment */
#define	SEGOFSET	(NBSEG-1)	/* byte offset into segment */
#define	SEGSHIFT	22		/* LOG2(NBSEG) */

/*
 * Size of kernel malloc arena in CLBYTES-sized logical pages
 */ 
#ifndef NKMEMCLUSTERS
#define	NKMEMCLUSTERS	(6 * 1024 * 1024 / CLBYTES)
#endif

/* pages ("clicks") (4096 bytes) to disk blocks */
#define	ctod(x)		((x) << (PGSHIFT - DEV_BSHIFT))
#define	dtoc(x)		((x) >> (PGSHIFT - DEV_BSHIFT))

/* pages to bytes */
#define	ctob(x)		((x) << PGSHIFT)
#define btoc(x)		(((x) + PGOFSET) >> PGSHIFT)

/* bytes to disk blocks */
#define	btodb(x)	((x) >> DEV_BSHIFT)
#define dbtob(x)	((x) << DEV_BSHIFT)

/*
 * Map a ``block device block'' to a file system block.
 * This should be device dependent, and should use the bsize
 * field from the disk label.
 * For now though just use DEV_BSIZE.
 */
#define	bdbtofsb(bn)	((bn) / (BLKDEV_IOSIZE/DEV_BSIZE))

/*
 * Mach derived conversion macros
 */
#define mips_round_page(x)	((((unsigned)(x)) + NBPG - 1) & ~(NBPG-1))
#define mips_trunc_page(x)	((unsigned)(x) & ~(NBPG-1))
#define mips_btop(x)		((unsigned)(x) >> PGSHIFT)
#define mips_ptob(x)		((unsigned)(x) << PGSHIFT)