/*
 * Mach Operating System
 * Copyright (c) 1991,1990,1989 Carnegie Mellon University
 * 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 ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS 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.
 */
/*
 * HISTORY
 * $Log: csw.S,v $
 * Revision 1.9  1998/07/20 06:58:28  roland
 * 1998-07-20  Roland McGrath  <roland@baalperazim.frob.com>
 *
 * 	* i386/csw.S (cproc_prepare): Take address of cthread_body as third
 * 	arg, so we don't have to deal with PIC magic to find its address
 * 	without producing a text reloc.
 * 	* cprocs.c (cproc_create): Pass &cthread_body to cproc_prepare.
 *
 * Revision 1.8  1997/04/04 01:31:16  thomas
 * Thu Apr  3 20:29:27 1997  Thomas Bushnell, n/BSG  <thomas@gnu.ai.mit.edu>
 *
 * 	* i386/csw.S: Define __ELF__ too.
 *
 * Revision 1.7  1996/10/24 19:30:10  thomas
 * Mon Oct 21 22:05:48 1996  Thomas Bushnell, n/BSG  <thomas@gnu.ai.mit.edu>
 *
 * 	* i386/csw.S (CALL_MCOUNT): New macro.
 * 	(cproc_swtich, cproc_start_wait, cproc_prepare): Use CALL_MCOUNT.
 *
 * Revision 1.6  1996/08/29 17:44:42  thomas
 * *** empty log message ***
 *
 * Revision 1.5  1995/10/04 20:55:28  roland
 * (JUMPTARGET): New macro, versions for [PIC] and not.
 * Use it in place of EXT.
 *
 * Revision 1.4  1995/10/04 20:22:17  roland
 * [PIC] (EXT): Redefine to use PLT.
 *
 * Revision 1.3  1995/05/12 18:35:55  roland
 * Use EXT macro instead of explicit underscores.
 *
# Revision 1.2  1994/05/04  19:01:50  mib
# entered into RCS
#
 * Revision 2.7  91/07/31  18:36:32  dbg
 * 	Fix for ANSI C preprocessor.
 * 	[91/07/30  17:35:16  dbg]
 *
 * Revision 2.6  91/05/14  17:56:56  mrt
 * 	Correcting copyright
 *
 * Revision 2.5  91/05/08  13:35:49  dbg
 * 	Unlock lock with a locked instruction (xchg).
 * 	[91/03/20            dbg]
 *
 * Revision 2.4  91/02/14  14:20:02  mrt
 * 	Changed to new Mach copyright
 * 	[91/02/13  12:15:27  mrt]
 *
 * Revision 2.3  91/01/08  16:46:20  rpd
 * 	Don't use Times - horta doesn't like it for some reason.
 * 	[91/01/06            rpd]
 *
 * Revision 2.2  90/05/03  15:54:37  dbg
 * 	Created.
 * 	[90/02/05            dbg]
 *
 */
#define ELF
#ifndef __ELF__
#define __ELF__
#endif
#include <ppc/asm.h>

/*
 * Suspend the current thread and resume the next one.
 *
 * void cproc_switch(int *cur, int *next, int *lock)
 */
ENTRY(cproc_switch,TAG_NO_FRAME_USED)
	stwu	%r1,-16(%r1)		/* update stack pointer */
	mflr	%r0			/* save link register */
	stw	%r0,20(%r1)
	stw	%r1,0(%r3)		/* save stack pointer in CUR */
	li	%r0,0
	stw	%r0,0(%r5)		/* unlock */
	lwz	%r1,0(%r4)		/* get new stack pointer from NEXT */
	lwz	%r0,20(%r1)		/* get link register */
	addi	%r1,%r1,16		/* update stack pointer */
	mtlr	%r0
	blr				/* return */

/*
 * Create a new stack frame for a 'waiting' thread,
 * save current thread's frame, and switch to waiting thread.
 *
 * void cproc_start_wait(int *cur,
 *			 cproc_t child,
 *			 int stackp,
 *			 int *lock)
 */
ENTRY(cproc_start_wait,TAG_NO_FRAME_USED)
	/* Not done yet, but it doesn't seem to be used.  */
	BREAKPOINT_TRAP

/*
 * Set up a thread's stack so that when cproc_switch switches to
 * it, it will start up as if it called
 * cproc_body(child)
 *
 * void cproc_prepare(cproc_t child, int *context, int stack,
 *		      void (*cthread_body)(cproc_t));
 */
ENTRY(cproc_prepare,TAG_NO_FRAME_USED)
	/* Not done yet, but this function is only used if the user
	   defines a maximum number of kernel threads by setting
	   cthread_max_kernel_threads.  */
	BREAKPOINT_TRAP