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/*
* Mach Operating System
* Copyright (c) 1991,1990 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.
*/
#include <mach/machine/asm.h>
#include <i386/proc_reg.h>
#include <i386/i386asm.h>
#include <i386/cpu_number.h>
.include "i386/cpu_number.S"
/*
* Context switch routines for i386.
*/
ENTRY(Load_context)
movl S_ARG0,%ecx /* get thread */
movl TH_KERNEL_STACK(%ecx),%ecx /* get kernel stack */
lea KERNEL_STACK_SIZE-IKS_SIZE-IEL_SIZE(%ecx),%edx
/* point to stack top */
CPU_NUMBER %eax
movl %ecx,CX(EXT(active_stacks),%eax) /* store stack address */
movl %edx,CX(EXT(kernel_stack),%eax) /* store stack top */
movl KSS_ESP(%ecx),%esp /* switch stacks */
movl KSS_ESI(%ecx),%esi /* restore registers */
movl KSS_EDI(%ecx),%edi
movl KSS_EBP(%ecx),%ebp
movl KSS_EBX(%ecx),%ebx
xorl %eax,%eax /* return zero (no old thread) */
jmp *KSS_EIP(%ecx) /* resume thread */
/*
* This really only has to save registers
* when there is no explicit continuation.
*/
ENTRY(Switch_context)
CPU_NUMBER %edx
movl CX(EXT(active_stacks),%edx),%ecx /* get old kernel stack */
movl %ebx,KSS_EBX(%ecx) /* save registers */
movl %ebp,KSS_EBP(%ecx)
movl %edi,KSS_EDI(%ecx)
movl %esi,KSS_ESI(%ecx)
popl KSS_EIP(%ecx) /* save return PC */
movl %esp,KSS_ESP(%ecx) /* save SP */
movl 0(%esp),%eax /* get old thread */
movl %ecx,TH_KERNEL_STACK(%eax) /* save old stack */
movl 4(%esp),%ebx /* get continuation */
movl %ebx,TH_SWAP_FUNC(%eax) /* save continuation */
movl 8(%esp),%esi /* get new thread */
movl TH_KERNEL_STACK(%esi),%ecx /* get its kernel stack */
lea KERNEL_STACK_SIZE-IKS_SIZE-IEL_SIZE(%ecx),%ebx
/* point to stack top */
movl %esi,CX(EXT(active_threads),%edx) /* new thread is active */
movl %ecx,CX(EXT(active_stacks),%edx) /* set current stack */
movl %ebx,CX(EXT(kernel_stack),%edx) /* set stack top */
movl KSS_ESP(%ecx),%esp /* switch stacks */
movl KSS_ESI(%ecx),%esi /* restore registers */
movl KSS_EDI(%ecx),%edi
movl KSS_EBP(%ecx),%ebp
movl KSS_EBX(%ecx),%ebx
jmp *KSS_EIP(%ecx) /* return old thread */
ENTRY(Thread_continue)
pushl %eax /* push the thread argument */
xorl %ebp,%ebp /* zero frame pointer */
call *%ebx /* call real continuation */
#if NCPUS > 1
/*
* void switch_to_shutdown_context(thread_t thread,
* void (*routine)(processor_t),
* processor_t processor)
*
* saves the kernel context of the thread,
* switches to the interrupt stack,
* continues the thread (with thread_continue),
* then runs routine on the interrupt stack.
*
* Assumes that the thread is a kernel thread (thus
* has no FPU state)
*/
ENTRY(switch_to_shutdown_context)
CPU_NUMBER %edx
movl EXT(active_stacks)(,%edx,4),%ecx /* get old kernel stack */
movl %ebx,KSS_EBX(%ecx) /* save registers */
movl %ebp,KSS_EBP(%ecx)
movl %edi,KSS_EDI(%ecx)
movl %esi,KSS_ESI(%ecx)
popl KSS_EIP(%ecx) /* save return PC */
movl %esp,KSS_ESP(%ecx) /* save SP */
movl 0(%esp),%eax /* get old thread */
movl %ecx,TH_KERNEL_STACK(%eax) /* save old stack */
movl $0,TH_SWAP_FUNC(%eax) /* clear continuation */
movl 4(%esp),%ebx /* get routine to run next */
movl 8(%esp),%esi /* get its argument */
movl EXT(interrupt_stack)(,%edx,4),%ecx /* point to its interrupt stack */
lea INTSTACK_SIZE(%ecx),%esp /* switch to it (top) */
pushl %eax /* push thread */
call EXT(thread_dispatch) /* reschedule thread */
addl $4,%esp /* clean stack */
pushl %esi /* push argument */
call *%ebx /* call routine to run */
hlt /* (should never return) */
#endif /* NCPUS > 1 */
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