root/lib/libc/arch/aarch64/sys/brk.S
/*      $OpenBSD: brk.S,v 1.7 2022/12/08 01:25:43 guenther Exp $        */
/*      $NetBSD: brk.S,v 1.7 2003/12/26 11:23:44 martin Exp $   */

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      from: @(#)brk.s 5.2 (Berkeley) 12/17/90
 */

#include "SYS.h"

        .globl  _end
        .globl  __curbrk

        .data
        .align  3
        .type   __minbrk,#object
__minbrk:
        .quad   _end
        END(__minbrk)

/*
 * Change the data segment size
 */
ENTRY_NB(brk)
        RETGUARD_SETUP(brk, x15)
#ifdef __PIC__
        /* Setup the GOT */
        adrp    x3, :got:__minbrk
        ldr     x1, [x3, #:got_lo12:__minbrk]
#else
        ldr     x1, .Lminbrk
#endif
        /* Get the minimum allowable brk address */
        ldr     x1, [x1]

        /*
         * Valid the address specified and set to the minimum
         * if the address is below minbrk.
         */
        cmp     x0, x1
        b.ge    1f
        mov     x0, x1
1:
        mov     x2, x0
        SYSTRAP(break)
        bcs     CERROR

#ifdef __PIC__
        adrp    x3, :got:__curbrk
        ldr     x1, [x3, #:got_lo12:__curbrk]
#else
        ldr     x1, .Lcurbrk
#endif
        /* Store the new address in curbrk */
        str     x2, [x1]

        /* Return 0 for success */
        mov     x0, #0x00000000
        RETGUARD_CHECK(brk, x15)
        ret

        .align  3
#if !defined(__PIC__)
.Lminbrk:
        .quad   __minbrk
.Lcurbrk:
        .quad   __curbrk
#endif
END(brk)
        .weak   brk