/* $NetBSD: swapcontext.S,v 1.4 2018/11/23 12:39:18 skrll 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 <machine/asm.h> #include "assym.h" #if defined(LIBC_SCCS) && !defined(lint) RCSID("$NetBSD: swapcontext.S,v 1.4 2018/11/23 12:39:18 skrll Exp $") #endif /* LIBC_SCCS && !lint */ /* LINTSTUB: int swapcontext(ucontext_t * restrict, ucontext_t * restrict); */ ENTRY(swapcontext) sub sp, sp, #32 /* allocate stack frame */ stp x29, x30, [sp, #16] /* save FP & LR */ add x29, sp, #16 /* new FP */ stp x0, x1, [sp, #0] /* save oucp (x0) & ucp (x1) */ bl _C_LABEL(_getcontext) /* getcontext(oucp) */ mov x3, x0 /* save return value */ ldp x2, x0, [sp, #0] /* load oucp (x2) & ucp (x0) */ ldp x29, x30, [sp, #16] /* restore FP & LR */ add sp, sp, #32 /* free stack frame */ /* * Assume _getcontext succeeded. */ mov x4, sp /* Get SP */ str x4, [x2, #_UC_REGS_SP] /* Adjust saved SP. */ str x30, [x2, #_UC_REGS_PC] /* Adjust saved PC. */ cbnz x3, 1f b _C_LABEL(setcontext) /* setcontext if getcontext succeeded */ 1: mov x0, x3 /* restore getcontext return value */ ret /* return on error from getcontext */ END(swapcontext) |