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

/*	$NetBSD: sbrk.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"

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

#ifdef WEAK_ALIAS
WEAK_ALIAS(sbrk, _sbrk)
#endif

ENTRY(_sbrk)
	auipc		t1, %pcrel_hi(_C_LABEL(__curbrk))
	addi		t1, t1, %pcrel_lo(_C_LABEL(__curbrk))
	PTR_L		t2, 0(t1)
	add		a0, a0, t2	// compute current break
	SYSTRAP(break)
	JUMP_TO_CERROR()		/* error */
	move		v0, t2		// return old val of curbrk from above
	PTR_S		a0, 0(t1)	// save current val of curbrk from above
	ret
1:
END(_sbrk)