lib/libc/i386/sys/brk.s

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 */

#if defined(SYSLIBC_SCCS) && !defined(lint)
        .asciz "@(#)brk.s       5.2 (Berkeley) 12/17/90"
#endif /* SYSLIBC_SCCS and not lint */

#include "SYS.h"

#define SYS_brk         17

        .globl  curbrk
        .globl  minbrk
ENTRY(_brk)
        jmp     ok

ENTRY(brk)
#ifdef PIC
        movl    4(%esp),%eax
        PIC_PROLOGUE
        movl    %edx,PIC_GOT(curbrk)    # set up GOT addressing
        movl    %ecx,PIC_GOT(minbrk)    #
        cmpl    %eax,(%ecx)
        PIC_EPILOGUE
        jl      ok
        movl    (%ecx),%eax
        movl    %eax,4(%esp)
ok:
        lea     SYS_brk,%eax
        LCALL(7,0)
        jb      err
        movl    4(%esp),%eax
        movl    %eax,(%edx)
        movl    $0,%eax
        ret
err:
        jmp     PIC_PLT(cerror)

#else

        movl    4(%esp),%eax
        cmpl    %eax,minbrk
        jl      ok
        movl    minbrk,%eax
        movl    %eax,4(%esp)
ok:
        lea     SYS_brk,%eax
        LCALL(7,0)
        jb      err
        movl    4(%esp),%eax
        movl    %eax,curbrk
        movl    $0,%eax
        ret
err:
        jmp     cerror
#endif