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/*
* 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
#undef __ELF__
#define __ELF__ 1
#include <mach/i386/asm.h>
#ifdef PIC
#define JUMPTARGET(name) EXT(name##@PLT)
#else
#define JUMPTARGET(name) EXT(name)
#endif
#ifdef PROF
#define CALL_MCOUNT \
pushl %ebp; movl %esp, %ebp; call JUMPTARGET(mcount); popl %ebp;
#else
#define CALL_MCOUNT
#endif
/*
* Suspend the current thread and resume the next one.
*
* void cproc_switch(int *cur, int *next, int *lock)
*/
ENTRY(cproc_switch)
CALL_MCOUNT
pushl %ebp /* save ebp */
movl %esp,%ebp /* set frame pointer to get arguments */
pushl %ebx /* save ebx */
pushl %esi /* esi */
pushl %edi /* edi */
movl B_ARG0,%eax /* get cur */
movl %esp,(%eax) /* save current esp */
movl B_ARG2,%edx /* get address of lock before switching */
/* stacks */
movl B_ARG1,%eax /* get next */
movl (%eax),%esp /* get new stack pointer */
xorl %eax,%eax /* unlock */
xchgl %eax,(%edx) /* the lock - now old thread can run */
popl %edi /* restore di */
popl %esi /* si */
popl %ebx /* bx */
popl %ebp /* and bp (don`t use "leave" - bp */
/* still points to old stack) */
ret
/*
* 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)
CALL_MCOUNT
pushl %ebp /* save ebp */
movl %esp,%ebp /* set frame pointer */
pushl %ebx /* save ebx */
pushl %esi /* esi */
pushl %edi /* edi */
movl B_ARG0,%eax /* get cur */
movl %esp,(%eax) /* save current esp */
movl B_ARG1,%eax /* get child thread */
movl B_ARG3,%edx /* point to lock before switching stack */
movl B_ARG2,%esp /* get new stack */
pushl %eax /* push child thread as argument */
movl $0,%ebp /* (clear frame pointer) */
xorl %eax,%eax /* unlock */
xchgl %eax,(%edx) /* the lock - now old thread can run */
call JUMPTARGET(cproc_waiting)/* call cproc_waiting */
/*NOTREACHED*/
/*
* 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)
CALL_MCOUNT
pushl %ebp /* save ebp */
movl %esp,%ebp /* set frame pointer */
movl B_ARG2,%edx /* get child`s stack */
subl $28,%edx
/* make room for context: */
/* 0 saved edi () */
/* 4 saved esi () */
/* 8 saved ebx () */
/* 12 saved ebp () */
/* 16 return PC from cproc_switch */
/* 20 return PC from cthread_body */
/* 24 argument to cthread_body */
movl $0,12(%edx) /* clear frame pointer */
movl B_ARG3,%ecx /* get address of cthread_body passed in */
movl %ecx,16(%edx) /* set child to resume at cthread_body */
movl $0,20(%edx) /* fake return address from cthread_body */
movl B_ARG0,%ecx /* get child thread pointer */
movl %ecx,24(%edx) /* set as argument to cthread_body */
movl B_ARG1,%ecx /* get pointer to context */
movl %edx,(%ecx) /* save context */
leave
ret
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