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_lwp.c revision 1.4 
      1 /*	$NetBSD: _lwp.c,v 1.4 2005/06/12 05:21:26 lukem Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *        This product includes software developed by the NetBSD
     18  *        Foundation, Inc. and its contributors.
     19  * 4. Neither the name of The NetBSD Foundation nor the names of its
     20  *    contributors may be used to endorse or promote products derived
     21  *    from this software without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     25  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     26  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     27  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     28  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     29  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     30  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     33  * POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 __RCSID("$NetBSD: _lwp.c,v 1.4 2005/06/12 05:21:26 lukem Exp $");
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include "namespace.h"
     42 #include <sys/types.h>
     43 #include <ucontext.h>
     44 #include <lwp.h>
     45 #include <stdlib.h>
     46 
     47 void
     48 _lwp_makecontext(ucontext_t *u, void (*start)(void *),
     49 		      void *arg, void *private,
     50 		      caddr_t stack_base, size_t stack_size)
     51 {
     52 	__greg_t *gr;
     53 	unsigned long *sp;
     54 
     55 	getcontext(u);
     56 	gr = u->uc_mcontext.__gregs;
     57 
     58 	u->uc_link = NULL;
     59 
     60 	u->uc_stack.ss_sp = stack_base;
     61 	u->uc_stack.ss_size = stack_size;
     62 
     63 	sp = (ulong *)(stack_base + stack_size);
     64 	sp = (ulong *)((ulong)sp & ~0x0f);
     65 
     66 	sp -= 8 + 8 + 6;
     67 
     68 	sp[8]  = (ulong)arg;
     69 	sp[14] = (ulong)sp - 2047;
     70 	sp[15] = (ulong)_lwp_exit - 8;
     71 
     72 	sp = (ulong *)((caddr_t)sp - 2047);
     73 
     74 	gr[_REG_PC] = (ulong) start;
     75 	gr[_REG_nPC] = (ulong) start + 4;
     76 
     77 	gr[_REG_O0] = (ulong) arg;
     78 	gr[_REG_O6] = (ulong) sp;
     79 	gr[_REG_O7] = (ulong)_lwp_exit - 8;
     80 }
     81