resumecontext.S revision 1.5
1 /* $NetBSD: resumecontext.S,v 1.5 2006/11/08 20:28:03 drochner Exp $ */ 2 3 /*- 4 * Copyright (c) 1999 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Klaus Klein. 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <machine/asm.h> 40 #include "SYS.h" 41 42 #if defined(LIBC_SCCS) && !defined(lint) 43 RCSID("$NetBSD: resumecontext.S,v 1.5 2006/11/08 20:28:03 drochner Exp $") 44 #endif /* LIBC_SCCS && !lint */ 45 46 /* 47 * This assembly-language implementation differs from the (obvious) 48 * C-language implementation only in not clobbering the previous 49 * function's return address (us), which is the point of the exercise. 50 */ 51 52 NENTRY(_resumecontext) /* profiling prologue would clobber TOS */ 53 leal -(4 + 776)(%esp),%ecx /* retaddr + sizeof (ucontext_t) */ 54 andl $~(0xf),%ecx /* align on _UC_UCONTEXT_ALIGN */ 55 movl %ecx,%esp 56 PIC_PROLOGUE 57 pushl %ecx 58 #ifdef PIC 59 call PIC_PLT(_C_LABEL(_getcontext)) 60 #else 61 call _C_LABEL(_getcontext) 62 #endif 63 addl $4,%esp 64 PIC_EPILOGUE 65 movl 4(%esp),%ecx /* uc_link */ 66 PIC_PROLOGUE 67 pushl %ecx /* argument for exit() or setcontext() */ 68 testl %ecx,%ecx /* link end? */ 69 jnz 9f /* watch out for local label use in PIC_* */ 70 71 /* normal exit */ 72 #ifdef PIC 73 call PIC_PLT(_C_LABEL(exit)) 74 #else 75 call _C_LABEL(exit) 76 #endif 77 /* NOTREACHED */ 78 79 9: 80 #ifdef PIC 81 call PIC_PLT(_C_LABEL(setcontext)) 82 #else 83 call _C_LABEL(setcontext) 84 #endif 85 /* NOTREACHED */ 86 87 /* something is wrong, pull the brake */ 88 pushl $-1 89 pushl %eax /* unused return address */ 90 SYSTRAP(exit) 91
Indexes created Mon Sep 29 21:09:56 GMT 2025