/*
 * 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.
 */

        .file   "memset.s"

/*
 * 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>

        ANSI_PRAGMA_WEAK(memset,function)

        ENTRY(memset)
        mov     %o0, %o5                ! copy sp before using it
        cmp     %o2, 7                  ! if small counts, just write bytes
        blu     .wrchar
        .empty                          ! following lable is ok in delay slot

.walign:btst    3, %o5                  ! if bigger, align to 4 bytes
        bz      .wrword
        andn    %o2, 3, %o3             ! create word sized count in %o3
        dec     %o2                     ! decrement count
        stb     %o1, [%o5]              ! clear a byte
        b       .walign
        inc     %o5                     ! next byte

.wrword:and     %o1, 0xff, %o1          ! generate a word filled with c
        sll     %o1, 8, %o4
        or      %o1, %o4, %o1
        sll     %o1, 16, %o4
        or      %o1, %o4, %o1
1:      st      %o1, [%o5]              ! word writing loop
        subcc   %o3, 4, %o3
        bnz     1b
        inc     4, %o5

        and     %o2, 3, %o2             ! leftover count, if any
.wrchar:deccc   %o2                     ! byte clearing loop
        inc     %o5
        bgeu,a  .wrchar
        stb     %o1, [%o5 + -1]         ! we've already incremented the address

        retl
        nop

        SET_SIZE(memset)