/* $NetBSD: resumecontext.S,v 1.8 2013/07/17 03:04:54 matt Exp $ */ /*- * Copyright (c) 2001 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Klaus Klein. * * 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: resumecontext.S,v 1.8 2013/07/17 03:04:54 matt Exp $") #endif /* LIBC_SCCS && !lint */ /* * This assembly-language implementation differs from the (obvious) * C-language implementation only in not clobbering the previous * function's return address (us), which is the point of the exercise. */ ENTRY(_resumecontext) subl #(4 + UC_SIZE),%sp /* retaddr preservation + ucontext_t */ lea (%sp),%a0 movl %a0,-(%sp) jbsr PIC_PLT(_C_LABEL(_getcontext)) movl (4 + UC_LINK)(%sp),(%sp) /* uc_link */ tstl (%sp) /* check for NULL */ jne 1f jbsr PIC_PLT(_C_LABEL(exit)) /* cleanly exit(0) */ jmp 2f 1: jbsr PIC_PLT(_C_LABEL(setcontext)) /* NOTREACHED */ /* But just in case... */ 2: movl #-1,(%sp) jbsr PIC_PLT(_C_LABEL(_exit)) /* NOTREACHED */ END(_resumecontext) |