/*
 * 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   "wsncmp.s"

/
/ Wide character wcsncpy() implementation
/
/ Algorithm based on Solaris 2.6 gen/strncpy.s implementation
/

#include <sys/asm_linkage.h>

        ANSI_PRAGMA_WEAK(wcsncmp,function)
        ANSI_PRAGMA_WEAK(wsncmp,function)

        ENTRY(wcsncmp)          /* (wchar *ws1, wchar_t *ws2, size_t n) */
        cmpq    %rdi,%rsi       / same string?
        je      .equal
        incq    %rdx            / will later predecrement this uint
.loop:
        decq    %rdx
        je      .equal          / Used all n chars?
        movl    (%rdi),%eax     / slodb ; scab
        cmpl    (%rsi),%eax
        jne     .notequal_0     / Are the bytes equal?
        testl   %eax,%eax
        je      .equal          / End of string?

        decq    %rdx
        je      .equal          / Used all n chars?
        movl    4(%rdi),%eax    / slodb ; scab
        cmpl    4(%rsi),%eax
        jne     .notequal_1     / Are the bytes equal?
        testl   %eax,%eax
        je      .equal          / End of string?

        decq    %rdx
        je      .equal          / Used all n chars?
        movl    8(%rdi),%eax    / slodb ; scab
        cmpl    8(%rsi),%eax
        jne     .notequal_2     / Are the bytes equal?
        testl   %eax,%eax
        je      .equal          / End of string?

        decq    %rdx
        je      .equal          / Used all n chars?
        movl    12(%rdi),%eax   / slodb ; scab
        cmpl    12(%rsi),%eax
        jne     .notequal_3     / Are the bytes equal?
        addq    $16,%rdi
        addq    $16,%rsi
        testl   %eax,%eax
        jne     .loop           / End of string?

.equal:
        xorl    %eax,%eax       / return 0
        ret

        .align  4
.notequal_3:
        addq    $4,%rsi
.notequal_2:
        addq    $4,%rsi
.notequal_1:
        addq    $4,%rsi
.notequal_0:
        subl    (%rsi),%eax     / return value is (*s1 - *--s2)
        ret
        SET_SIZE(wcsncmp)

        ENTRY(wsncmp)
        jmp     wcsncmp         / tail call into wcsncmp
        SET_SIZE(wsncmp)