/*
 * 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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 */

        .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);
 *      }
 *
 * 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)