/*

 * 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);

 *	}

 */

#include <sys/asm_linkage.h>

#include <sys/sun4asi.h>

	ANSI_PRAGMA_WEAK(memset,function)

#define	ALIGN8(X)	(((X) + 7) & ~7)

	.section        ".text"

	.align 32

	ENTRY(memset)

	cmp	%o2, 12			! if small counts, just write bytes

	bgeu,pn	%ncc, .wrbig

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

.wrchar:

	deccc   %o2			! byte clearing loop

        inc     %o5

	bgeu,a,pt %ncc, .wrchar

        stb     %o1, [%o5 + -1]         ! we've already incremented the address

        retl

	.empty	! next instruction is safe, %o0 still good

.wrbig:

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

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

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

        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)

.blkchk:

	sll     %o1, 8, %o3

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

        sll     %o1, 16, %o3

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

	cmp     %o2, 4095		! if large count use Block ld/st

	sllx	%o1, 32, %o3

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

        bgu,a,pn %ncc, .blkwr		! Do block write for large count

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

	and	%o2, 24, %o3		! o3 is {0, 8, 16, 24}

1:	subcc	%o3, 8, %o3		! double-word loop

	add	%o5, 8, %o5

	bgeu,a,pt %ncc, 1b

	stx	%o1, [%o5 - 8]		! already incremented the address

	andncc	%o2, 31, %o4		! o4 has 32 byte aligned count

	bz,pn	%ncc, 3f		! First instruction of icache line

2:

	subcc	%o4, 32, %o4		! main loop, 32 bytes per iteration

	stx	%o1, [%o5 - 8]

	stx	%o1, [%o5]

	stx	%o1, [%o5 + 8]

	stx	%o1, [%o5 + 16]

	bnz,pt	%ncc, 2b

	add	%o5, 32, %o5

3:	

	and	%o2, 7, %o2		! o2 has the remaining bytes (<8)

4:

	deccc   %o2                     ! byte clearing loop

        inc     %o5

        bgeu,a,pt %ncc, 4b

        stb     %o1, [%o5 - 9]		! already incremented the address

	retl

	nop				! %o0 still preserved

.blkwr:

        bz,pn   %ncc, .blalign		! 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

	! sp1 is block aligned                                     

.blalign:

        rd      %fprs, %g1              ! g1 = fprs

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

	andcc	%g1, 0x4, %g1		! fprs.du = fprs.dl = 0

	bz,a	%ncc, 2f		! Is fprs.fef == 0 

        wr      %g0, 0x4, %fprs         ! fprs.fef = 1

2:

	brnz,pn	%o1, 3f			! %o1 is safe to check all 64-bits

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

	fzero   %d0

	fzero   %d2

	fzero   %d4

	fzero   %d6

	fmuld   %d0, %d0, %d8

	fzero   %d10

	ba	4f

	fmuld   %d0, %d0, %d12

3:

	! allocate 8 bytes of scratch space on the stack

	add	%sp, -SA(16), %sp

	stx	%o1, [%sp + STACK_BIAS + ALIGN8(MINFRAME)]  ! move %o1 to %d0

	ldd	[%sp + STACK_BIAS + ALIGN8(MINFRAME)], %d0

	fmovd	%d0, %d2

	add	%sp, SA(16), %sp	! deallocate the scratch space

	fmovd	%d0, %d4	

	fmovd	%d0, %d6	

	fmovd	%d0, %d8

	fmovd	%d0, %d10	

	fmovd	%d0, %d12	

4:	

	fmovd	%d0, %d14

	! 1st quadrant has 64 bytes of c

	! instructions 32-byte aligned here

        stda    %d0, [%o5]ASI_BLK_P

        subcc   %o4, 64, %o4

        bgu,pt	%ncc, 4b

        add     %o5, 64, %o5

	! Set the remaining doubles

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

	blu,pn  %ncc, 6f

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

5:	

	std     %d0, [%o5]		! store the doubles

	subcc   %o3, 8, %o3

	bgeu,pt	%ncc, 5b

        add     %o5, 8, %o5      

6:

	! Set the remaining bytes

	brz	%o2, .exit		! safe to check all 64-bits

#if 0

	! Terminate the copy with a partial store. (bug 1200071 does not apply)

	! The data should be at d0

        dec     %o2                     ! needed to get the mask right

	edge8n	%g0, %o2, %o4

	stda	%d0, [%o5]%o4, ASI_PST8_P

#else

7:	

	deccc	%o2

	stb	%o1, [%o5]

	bgu,pt	%ncc, 7b

	inc	%o5

#endif

.exit:	

        membar  #StoreLoad|#StoreStore

        retl				! %o0 was preserved

        wr	%g1, %g0, %fprs         ! fprs = g1  restore fprs

	SET_SIZE(memset)