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_lwp.c revision 1.2 
      1 /*	$NetBSD: _lwp.c,v 1.2 2003/01/18 11:17:45 thorpej 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/types.h>
     37 #include <ucontext.h>
     38 #include <lwp.h>
     39 #include <stdlib.h>
     40 
     41 void
     42 _lwp_makecontext(ucontext_t *u, void (*start)(void *),
     43 		      void *arg, void *private,
     44 		      caddr_t stack_base, size_t stack_size)
     45 {
     46 	__greg_t *gr;
     47 	unsigned long *sp;
     48 
     49 	getcontext(u);
     50 	gr = u->uc_mcontext.__gregs;
     51 
     52 	u->uc_link = NULL;
     53 
     54 	u->uc_stack.ss_sp = stack_base;
     55 	u->uc_stack.ss_size = stack_size;
     56 
     57 	sp = (ulong *)(stack_base + stack_size);
     58 	sp = (ulong *)((ulong)sp & ~0x0f);
     59 
     60 	sp -= 8 + 8 + 6;
     61 
     62 	sp[8]  = (ulong)arg;
     63 	sp[14] = (ulong)sp - 2047;
     64 	sp[15] = (ulong)_lwp_exit - 8;
     65 
     66 	sp = (ulong *)((caddr_t)sp - 2047);
     67 
     68 	gr[_REG_PC] = (ulong) start;
     69 	gr[_REG_nPC] = (ulong) start + 4;
     70 
     71 	gr[_REG_O0] = (ulong) arg;
     72 	gr[_REG_O6] = (ulong) sp;
     73 	gr[_REG_O7] = (ulong)_lwp_exit - 8;
     74 }
     75