/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

/*

 * char *memset(sp, c, n)

 *

 * Set an array of n chars starting at sp to the character c.

 * Return sp.

 *

 * Fast assembler language version of the following C-program for memset

 * which represents the `standard' for the C-library.

 *

 *	void *

 *	memset(void *sp1, int c, size_t n)

 *	{

 *	    if (n != 0) {

 *		char *sp = sp1;

 *		do {

 *		    *sp++ = (char)c;

 *		} while (--n != 0);

 *	    }

 *	    return (sp1);

 *	}

 *

 * Flow :

 *

 *	For small 6 or fewer bytes stores, bytes will be stored.

 *

 *	For less than 32 bytes stores, align the address on 4 byte boundary.

 *	Then store as many 4-byte chunks, followed by trailing bytes.

 *

 *	For sizes greater than 32 bytes, align the address on 8 byte boundary.

 *	if (count > 64) {

 *		store as many 8-bytes chunks to block align the address

 *		store using ASI_BLK_INIT_ST_QUAD_LDD_P

 *	}

 *	Store as many 8-byte chunks, followed by trialing bytes.

 *		

 */

#include <sys/asm_linkage.h>

#include <sys/niagaraasi.h>

#include <sys/asi.h>

	ANSI_PRAGMA_WEAK(memset,function)

	.section        ".text"

	.align 32

	ENTRY(memset)

	mov	%o0, %o5		! copy sp1 before using it

	cmp	%o2, 7			! if small counts, just write bytes

	blu,pn	%ncc, .wrchar

	and	%o1, 0xff, %o1		! o1 is (char)c

	sll	%o1, 8, %o3

	or	%o1, %o3, %o1		! now o1 has 2 bytes of c

	sll	%o1, 16, %o3

	cmp	%o2, 0x20

	blu,pn	%ncc, .wdalign

	or	%o1, %o3, %o1		! now o1 has 4 bytes of c

	sllx	%o1, 32, %o3

	or	%o1, %o3, %o1		! now o1 has 8 bytes of c

.dbalign:

	andcc	%o5, 7, %o3		! is sp1 aligned on a 8 byte bound

	bz,pt	%ncc, .blkalign		! already double aligned

	sub	%o3, 8, %o3		! -(bytes till double aligned)

	add	%o2, %o3, %o2		! update o2 with new count

	! Set -(%o3) bytes till sp1 double aligned

1:	stb	%o1, [%o5]		! there is at least 1 byte to set

	inccc	%o3			! byte clearing loop 

	bl,pt	%ncc, 1b

	inc	%o5 

	! Now sp1 is double aligned (sp1 is found in %o5)

.blkalign:

	mov	ASI_BLK_INIT_ST_QUAD_LDD_P, %asi

	cmp	%o2, 0x40		! check if there are 64 bytes to set

	blu,pn	%ncc, 5f

	mov	%o2, %o3

	andcc	%o5, 63, %o3		! is sp1 block aligned?

	bz,pt	%ncc, .blkwr		! now block aligned

	sub	%o3, 64, %o3		! o3 is -(bytes till block aligned)

	add	%o2, %o3, %o2		! o2 is the remainder

	! Store -(%o3) bytes till dst is block (64 byte) aligned.

	! Use double word stores.

	! Recall that dst is already double word aligned

1:

	stx	%o1, [%o5]

	addcc	%o3, 8, %o3

	bl,pt	%ncc, 1b

	add	%o5, 8, %o5

	! Now sp1 is block aligned

.blkwr:

	and	%o2, 63, %o3		! calc bytes left after blk store.

	andn	%o2, 63, %o4		! calc size of blocks in bytes

	cmp	%o4, 0x100		! check if there are 256 bytes to set

	blu,pn	%ncc, 3f

	nop

2:

	stxa	%o1, [%o5+0x0]%asi

	stxa	%o1, [%o5+0x40]%asi

	stxa	%o1, [%o5+0x80]%asi

	stxa	%o1, [%o5+0xc0]%asi

	stxa	%o1, [%o5+0x8]%asi

	stxa	%o1, [%o5+0x10]%asi

	stxa	%o1, [%o5+0x18]%asi

	stxa	%o1, [%o5+0x20]%asi

	stxa	%o1, [%o5+0x28]%asi

	stxa	%o1, [%o5+0x30]%asi

	stxa	%o1, [%o5+0x38]%asi

	stxa	%o1, [%o5+0x48]%asi

	stxa	%o1, [%o5+0x50]%asi

	stxa	%o1, [%o5+0x58]%asi

	stxa	%o1, [%o5+0x60]%asi

	stxa	%o1, [%o5+0x68]%asi

	stxa	%o1, [%o5+0x70]%asi

	stxa	%o1, [%o5+0x78]%asi

	stxa	%o1, [%o5+0x88]%asi

	stxa	%o1, [%o5+0x90]%asi

	stxa	%o1, [%o5+0x98]%asi

	stxa	%o1, [%o5+0xa0]%asi

	stxa	%o1, [%o5+0xa8]%asi

	stxa	%o1, [%o5+0xb0]%asi

	stxa	%o1, [%o5+0xb8]%asi

	stxa	%o1, [%o5+0xc8]%asi

	stxa	%o1, [%o5+0xd0]%asi

	stxa	%o1, [%o5+0xd8]%asi

	stxa	%o1, [%o5+0xe0]%asi

	stxa	%o1, [%o5+0xe8]%asi

	stxa	%o1, [%o5+0xf0]%asi

	stxa	%o1, [%o5+0xf8]%asi

	sub	%o4, 0x100, %o4

	cmp	%o4, 0x100

	bgu,pt	%ncc, 2b

	add	%o5, 0x100, %o5

3:

	cmp	%o4, 0x40		! check if 64 bytes to set

	blu	%ncc, 5f

	nop

4:	

	stxa	%o1, [%o5+0x0]%asi

	stxa	%o1, [%o5+0x8]%asi

	stxa	%o1, [%o5+0x10]%asi

	stxa	%o1, [%o5+0x18]%asi

	stxa	%o1, [%o5+0x20]%asi

	stxa	%o1, [%o5+0x28]%asi

	stxa	%o1, [%o5+0x30]%asi

	stxa	%o1, [%o5+0x38]%asi

	subcc	%o4, 0x40, %o4

	bgu,pt	%ncc, 4b

	add	%o5, 0x40, %o5

5:

	! Set the remaining doubles

	membar	#Sync

	mov	ASI_PNF, %asi		! restore %asi to default

					! ASI_PRIMARY_NOFAULT value

	subcc	%o3, 8, %o3		! Can we store any doubles?

	blu,pn	%ncc, .wrchar

	and	%o2, 7, %o2		! calc bytes left after doubles

6:

	stx	%o1, [%o5]		! store the doubles

	subcc	%o3, 8, %o3

	bgeu,pt	%ncc, 6b

	add	%o5, 8, %o5

	ba	.wrchar

	nop

.wdalign:			

	andcc	%o5, 3, %o3		! is sp1 aligned on a word boundary

	bz,pn	%ncc, .wrword

	andn	%o2, 3, %o3		! create word sized count in %o3

	dec	%o2			! decrement count

	stb	%o1, [%o5]		! clear a byte

	b	.wdalign

	inc	%o5			! next byte

.wrword:

	st	%o1, [%o5]		! 4-byte writing loop

	subcc	%o3, 4, %o3

	bnz,pt	%ncc, .wrword

	inc	4, %o5

	and	%o2, 3, %o2		! leftover count, if any

.wrchar:

	! Set the remaining bytes, if any

	cmp	%o2, 0

	be	%ncc, .exit

	nop

7:

	deccc	%o2

	stb	%o1, [%o5]

	bgu,pt	%ncc, 7b

	inc	%o5

.exit:

	retl				! %o0 was preserved

	nop

	SET_SIZE(memset)