/*
 * Copyright 1991-1998 by Open Software Foundation, Inc. 
 *              All Rights Reserved 
 *  
 * Permission to use, copy, modify, and distribute this software and 
 * its documentation for any purpose and without fee is hereby granted, 
 * provided that the above copyright notice appears in all copies and 
 * that both the copyright notice and this permission notice appear in 
 * supporting documentation. 
 *  
 * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE 
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
 * FOR A PARTICULAR PURPOSE. 
 *  
 * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR 
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, 
 * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 
 * 
 */
/*
 * MkLinux
 */
/*
 * Mach Operating System
 * Copyright (c) 1989 Carnegie Mellon University.
 * Copyright (c) 1990,1991 The University of Utah and
 * the Center for Software Science (CSS).
 * All rights reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON, THE UNIVERSITY OF UTAH AND CSS ALLOW FREE USE OF
 * THIS SOFTWARE IN ITS "AS IS" CONDITION, AND DISCLAIM ANY LIABILITY
 * OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF
 * THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 *
 * 	Utah $Hdr$
 */

#include "../cthreads.h"
#include "../cthread_internals.h"

#include <mach.h>

/*
 * Set up the initial state of a MACH thread so that it will invoke
 * routine(child) when it is resumed.
 */
void
cproc_setup(cproc_t child, thread_t thread, void (*routine)(cproc_t))
{
	extern unsigned int __hurd_threadvar_max; /* GNU */
	register int *top = (int *)
	  cproc_stack_base (child, sizeof (ur_cthread_t *) +
			    /* Account for GNU per-thread variables.  */
			    __hurd_threadvar_max *
			    sizeof (long int));
	struct ppc_thread_state state;
	kern_return_t r;
	unsigned size;

	/*
	 * Set up ppc call frame and registers.
	 */
	size = PPC_THREAD_STATE_COUNT;
	MACH_CALL(thread_get_state(thread, PPC_THREAD_STATE, 
				   (thread_state_t) &state, &size), r);

	/*
	 * set the PC to point to routine.
	 */
	state.srr0 = (unsigned)routine;

	/*
	 * setup the first argument to routine to be the address of child.
	 */
	state.r3 = (int) child;

	/*
	 * establish a user stack for this thread. There is no guarentee
	 * that the stack is aligned correctly. We have to align it to
	 * a double word boundary.  (In fact, if CTHREAD_STACK_OFFSET
	 * is aligned, then so is the stack.  But little things can go
	 * wrong.)
	 */
	top -= /* CTHREAD_STACK_OFFSET */ 128;
	top -= 16; /* Top frame on stack */
	*top = 0;  /* Mark NULL backpointer */
	state.r1 = (unsigned int) top;

	MACH_CALL(thread_set_state(thread, PPC_THREAD_STATE,
				   (thread_state_t) &state,
				   PPC_THREAD_STATE_COUNT),r);
}

#ifdef	cthread_sp
#undef	cthread_sp
#endif

int
cthread_sp()
{
	int x;
#ifdef	__GNUC__
	/* GCC generates a warning if we return the address of a local
	 * variable, so we special-case this
	 */
	__asm__ ("mr %0,1" : "=r" (x));
	return x;
#else	/* __GNUC__ */
	return (int) &x;
#endif	/* __GNUC__ */
}