1/* $NetBSD: swapcontext.S,v 1.1 2014/08/10 05:47:36 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 <machine/asm.h> 33#include "assym.h" 34 35#if defined(LIBC_SCCS) && !defined(lint) 36 RCSID("$NetBSD: swapcontext.S,v 1.1 2014/08/10 05:47:36 matt Exp $") 37#endif /* LIBC_SCCS && !lint */ 38 39/* LINTSTUB: int swapcontext(ucontext_t * restrict, ucontext_t * restrict); */ 40 41ENTRY(swapcontext) 42 sub sp, sp, #32 /* allocate stack frame */ 43 stp x29, x30, [sp, #16] /* save FP & RA */ 44 add x29, sp, #16 /* new FP */ 45 stp x0, x1, [sp, #0] /* save oucp & ucp */ 46 47 bl _C_LABEL(_getcontext) /* getcontext(oucp) */ 48 mov x3, x0 /* save return value */ 49 50 ldp x2, x0, [sp, #0] /* restore oucp & ucp */ 51 ldp x29, x30, [sp, #16] /* restore FP & RA */ 52 add sp, sp, #32 /* free stack frame */ 53 54 /* 55 * Assume _getcontext succeeded. 56 */ 57 mov x4, sp /* Get SP */ 58 str x4, [x2, #_UC_REGS_SP] /* Adjust saved SP. */ 59 str x30, [x2, #_UC_REGS_PC] /* Adjust saved LR. */ 60 61 cbz x3, _C_LABEL(setcontext)/* setcontext if getcontext succeeded */ 62 mov x0, x3 /* restore getcontext return value */ 63 ret /* return on error from getcontext */ 64END(swapcontext) 65