/*      $OpenBSD: brk.S,v 1.5 2023/12/10 16:45:52 deraadt Exp $ */
/*
 * Copyright (c) 2021 Dale Rahn <drahn@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "SYS.h"

        .extern __curbrk
        .extern _end

        .data
        .align 3
__minbrk:
        .dword _end
        

ENTRY_NB(brk)
        RETGUARD_SETUP(brk, t6)
        lla     t1, __minbrk
        ld      t5, 0(t1)
        bgeu    a0, t5, .L_brk_call
        mv      a0, t5
        
.L_brk_call:
        mv      a2, a0
        lla     t1, __curbrk

        li t0, SYS_break
99:     ecall
        PINSYSCALL(SYS_break, 99b)

        /* check for error */
        beqz    t0, .L_brk_ok

        sw      a0, TP_OFFSET_ERRNO(tp)
        li      a0, -1
        j       .L_done

        /* update, __curbrk and return */
.L_brk_ok:
        sd      a2, 0(t1)
        li      a0, 0           /* # return 0 */
.L_done:
        RETGUARD_CHECK(brk, t6);
        ret
END(brk)
        .weak   brk