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sbrk.S revision 1.1 
      1 /*	$NetBSD: sbrk.S,v 1.1 2014/09/19 17:36:25 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2014 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Matt Thomas of 3am Software Foundry.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include "SYS.h"
     33 
     34 	.hidden	_C_LABEL(__curbrk)
     35 	.globl	_C_LABEL(__curbrk)
     36 	.globl	_C_LABEL(_end)
     37 
     38 #ifdef WEAK_ALIAS
     39 WEAK_ALIAS(sbrk, _sbrk)
     40 #endif
     41 
     42 ENTRY(_sbrk)
     43 	auipc		t1, %pcrel_hi(_C_LABEL(__curbrk))
     44 	addi		t1, t1, %pcrel_lo(_C_LABEL(__curbrk))
     45 	PTR_L		t2, 0(t1)
     46 	add		a0, a0, t2	// compute current break
     47 	SYSTRAP(break)
     48 	JUMP_TO_CERROR()		/* error */
     49 	move		v0, t2		// return old val of curbrk from above
     50 	PTR_S		a0, 0(t1)	// save current val of curbrk from above
     51 	ret
     52 1:
     53 END(_sbrk)
     54