xref: /src/lib/libc/arch/riscv/sys/brk.S

/*	$NetBSD: brk.S,v 1.1 2014/09/19 17:36:25 matt Exp $	*/

/*-
 * Copyright (c) 2014 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matt Thomas of 3am Software Foundry.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include "SYS.h"

#if defined(LIBC_SCCS) && !defined(lint)
	RCSID("$NetBSD: brk.S,v 1.1 2014/09/19 17:36:25 matt Exp $")
#endif /* LIBC_SCCS and not lint */

	.hidden	_C_LABEL(__minbrk)
	.hidden	_C_LABEL(__curbrk)
	.globl	_C_LABEL(__minbrk)
	.globl	_C_LABEL(__curbrk)
	.globl	_C_LABEL(_end)

#ifdef WEAK_ALIAS
WEAK_ALIAS(brk, _brk)
#endif

	.data
	.p2align	PTR_SCALESHIFT
_C_LABEL(__minbrk):
	PTR_WORD	_C_LABEL(_end)
_C_LABEL(__curbrk):
	PTR_WORD	_C_LABEL(_end)

	.text

ENTRY(_brk)
	auipc	t1, %pcrel_hi(_C_LABEL(__minbrk))
	addi	t1, t1, %pcrel_lo(_C_LABEL(__minbrk))
	PTR_L	v0, 0(t1)
	bgeu	a0, v0, 1f
	move	a0, v0		# dont allow break < minbrk
1:
	SYSTRAP(break)
	JUMP_TO_CERROR()				/* error */
	PTR_S	a0, __SIZEOF_POINTER__(t1)		/* success */
	move	v0, zero
	ret
END(_brk)