/* -*- mode: asm -*-
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*
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* linux/arch/m68k/kernel/entry.S
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file README.legal in the main directory of this archive
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* for more details.
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*
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* Linux/m68k support by Hamish Macdonald
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*
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* 68060 fixes by Jesper Skov
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*
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*/
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/*
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* entry.S contains the system-call and fault low-level handling routines.
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* This also contains the timer-interrupt handler, as well as all interrupts
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* and faults that can result in a task-switch.
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*
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* NOTE: This code handles signal-recognition, which happens every time
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* after a timer-interrupt and after each system call.
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*
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*/
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/*
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* 12/03/96 Jes: Currently we only support m68k single-cpu systems, so
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* all pointers that used to be 'current' are now entry
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* number 0 in the 'current_set' list.
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*
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* 6/05/00 RZ: addedd writeback completion after return from sighandler
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* for 68040
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*/
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#include <linux/linkage.h>
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#include <asm/errno.h>
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#include <asm/setup.h>
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#include <asm/segment.h>
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#include <asm/traps.h>
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#include <asm/unistd.h>
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#include <asm/asm-offsets.h>
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#include <asm/entry.h>
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.globl system_call, buserr, trap, resume
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.globl sys_call_table
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.globl __sys_fork, __sys_clone, __sys_vfork
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.globl bad_interrupt
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.globl auto_irqhandler_fixup
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.globl user_irqvec_fixup
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.text
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ENTRY(__sys_fork)
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SAVE_SWITCH_STACK
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jbsr sys_fork
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lea %sp@(24),%sp
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rts
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ENTRY(__sys_clone)
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SAVE_SWITCH_STACK
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pea %sp@(SWITCH_STACK_SIZE)
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jbsr m68k_clone
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lea %sp@(28),%sp
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rts
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ENTRY(__sys_vfork)
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SAVE_SWITCH_STACK
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jbsr sys_vfork
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lea %sp@(24),%sp
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rts
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ENTRY(__sys_clone3)
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SAVE_SWITCH_STACK
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pea %sp@(SWITCH_STACK_SIZE)
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jbsr m68k_clone3
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lea %sp@(28),%sp
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rts
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ENTRY(sys_sigreturn)
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SAVE_SWITCH_STACK
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movel %sp,%sp@- | switch_stack pointer
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pea %sp@(SWITCH_STACK_SIZE+4) | pt_regs pointer
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jbsr do_sigreturn
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addql #8,%sp
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RESTORE_SWITCH_STACK
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rts
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ENTRY(sys_rt_sigreturn)
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SAVE_SWITCH_STACK
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movel %sp,%sp@- | switch_stack pointer
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pea %sp@(SWITCH_STACK_SIZE+4) | pt_regs pointer
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jbsr do_rt_sigreturn
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addql #8,%sp
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RESTORE_SWITCH_STACK
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rts
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ENTRY(buserr)
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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jbsr buserr_c
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addql #4,%sp
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jra ret_from_exception
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ENTRY(trap)
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- | stack frame pointer argument
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jbsr trap_c
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addql #4,%sp
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jra ret_from_exception
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| After a fork we jump here directly from resume,
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| so that %d1 contains the previous task
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| schedule_tail now used regardless of CONFIG_SMP
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ENTRY(ret_from_fork)
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movel %d1,%sp@-
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jsr schedule_tail
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addql #4,%sp
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jra ret_from_exception
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ENTRY(ret_from_kernel_thread)
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| a3 contains the kernel thread payload, d7 - its argument
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movel %d1,%sp@-
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jsr schedule_tail
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movel %d7,(%sp)
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jsr %a3@
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addql #4,%sp
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jra ret_from_exception
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#if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
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#ifdef TRAP_DBG_INTERRUPT
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.globl dbginterrupt
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ENTRY(dbginterrupt)
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@- /* stack frame pointer argument */
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jsr dbginterrupt_c
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addql #4,%sp
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jra ret_from_exception
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#endif
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ENTRY(reschedule)
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/* save top of frame */
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pea %sp@
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jbsr set_esp0
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addql #4,%sp
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pea ret_from_exception
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jmp schedule
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ENTRY(ret_from_user_signal)
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moveq #__NR_sigreturn,%d0
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trap #0
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ENTRY(ret_from_user_rt_signal)
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movel #__NR_rt_sigreturn,%d0
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trap #0
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#else
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do_trace_entry:
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movel #-ENOSYS,%sp@(PT_OFF_D0)| needed for strace
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subql #4,%sp
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SAVE_SWITCH_STACK
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jbsr syscall_trace
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RESTORE_SWITCH_STACK
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addql #4,%sp
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addql #1,%d0 | optimization for cmpil #-1,%d0
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jeq ret_from_syscall
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movel %sp@(PT_OFF_ORIG_D0),%d0
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cmpl #NR_syscalls,%d0
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jcs syscall
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jra ret_from_syscall
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badsys:
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movel #-ENOSYS,%sp@(PT_OFF_D0)
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jra ret_from_syscall
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do_trace_exit:
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subql #4,%sp
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SAVE_SWITCH_STACK
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jbsr syscall_trace
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RESTORE_SWITCH_STACK
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addql #4,%sp
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jra .Lret_from_exception
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ENTRY(ret_from_signal)
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movel %curptr@(TASK_STACK),%a1
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tstb %a1@(TINFO_FLAGS+2)
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jge 1f
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jbsr syscall_trace
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1: RESTORE_SWITCH_STACK
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addql #4,%sp
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/* on 68040 complete pending writebacks if any */
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#ifdef CONFIG_M68040
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bfextu %sp@(PT_OFF_FORMATVEC){#0,#4},%d0
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subql #7,%d0 | bus error frame ?
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jbne 1f
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movel %sp,%sp@-
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jbsr berr_040cleanup
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addql #4,%sp
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1:
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#endif
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jra .Lret_from_exception
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ENTRY(system_call)
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SAVE_ALL_SYS
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GET_CURRENT(%d1)
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movel %d1,%a1
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| save top of frame
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movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
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| syscall trace?
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tstb %a1@(TINFO_FLAGS+2)
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jmi do_trace_entry
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cmpl #NR_syscalls,%d0
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jcc badsys
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syscall:
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jbsr @(sys_call_table,%d0:l:4)@(0)
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movel %d0,%sp@(PT_OFF_D0) | save the return value
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ret_from_syscall:
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|oriw #0x0700,%sr
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movel %curptr@(TASK_STACK),%a1
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movew %a1@(TINFO_FLAGS+2),%d0
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jne syscall_exit_work
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1: RESTORE_ALL
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syscall_exit_work:
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btst #5,%sp@(PT_OFF_SR) | check if returning to kernel
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bnes 1b | if so, skip resched, signals
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lslw #1,%d0
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jcs do_trace_exit
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jmi do_delayed_trace
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lslw #8,%d0
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jne do_signal_return
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pea resume_userspace
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jra schedule
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ENTRY(ret_from_exception)
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.Lret_from_exception:
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btst #5,%sp@(PT_OFF_SR) | check if returning to kernel
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bnes 1f | if so, skip resched, signals
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| only allow interrupts when we are really the last one on the
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| kernel stack, otherwise stack overflow can occur during
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| heavy interrupt load
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andw #ALLOWINT,%sr
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resume_userspace:
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movel %curptr@(TASK_STACK),%a1
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moveb %a1@(TINFO_FLAGS+3),%d0
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jne exit_work
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1: RESTORE_ALL
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exit_work:
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| save top of frame
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movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
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lslb #1,%d0
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jne do_signal_return
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pea resume_userspace
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jra schedule
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do_signal_return:
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|andw #ALLOWINT,%sr
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subql #4,%sp | dummy return address
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SAVE_SWITCH_STACK
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pea %sp@(SWITCH_STACK_SIZE)
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bsrl do_notify_resume
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addql #4,%sp
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RESTORE_SWITCH_STACK
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addql #4,%sp
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jbra resume_userspace
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do_delayed_trace:
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bclr #7,%sp@(PT_OFF_SR) | clear trace bit in SR
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pea 1 | send SIGTRAP
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movel %curptr,%sp@-
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pea LSIGTRAP
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jbsr send_sig
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addql #8,%sp
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addql #4,%sp
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jbra resume_userspace
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/* This is the main interrupt handler for autovector interrupts */
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ENTRY(auto_inthandler)
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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| put exception # in d0
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bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
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subw #VEC_SPUR,%d0
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movel %sp,%sp@-
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movel %d0,%sp@- | put vector # on stack
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auto_irqhandler_fixup = . + 2
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jsr do_IRQ | process the IRQ
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addql #8,%sp | pop parameters off stack
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jra ret_from_exception
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/* Handler for user defined interrupt vectors */
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ENTRY(user_inthandler)
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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| put exception # in d0
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bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
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user_irqvec_fixup = . + 2
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subw #VEC_USER,%d0
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movel %sp,%sp@-
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movel %d0,%sp@- | put vector # on stack
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jsr do_IRQ | process the IRQ
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addql #8,%sp | pop parameters off stack
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jra ret_from_exception
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/* Handler for uninitialized and spurious interrupts */
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ENTRY(bad_inthandler)
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SAVE_ALL_INT
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GET_CURRENT(%d0)
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movel %sp,%sp@-
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jsr handle_badint
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addql #4,%sp
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jra ret_from_exception
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resume:
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/*
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* Beware - when entering resume, prev (the current task) is
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* in a0, next (the new task) is in a1,so don't change these
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* registers until their contents are no longer needed.
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*/
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/* save sr */
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movew %sr,%a0@(TASK_THREAD+THREAD_SR)
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/* save fs (sfc,%dfc) (may be pointing to kernel memory) */
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movec %sfc,%d0
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movew %d0,%a0@(TASK_THREAD+THREAD_FS)
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/* save usp */
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/* it is better to use a movel here instead of a movew 8*) */
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movec %usp,%d0
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movel %d0,%a0@(TASK_THREAD+THREAD_USP)
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/* save non-scratch registers on stack */
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SAVE_SWITCH_STACK
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/* save current kernel stack pointer */
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movel %sp,%a0@(TASK_THREAD+THREAD_KSP)
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/* save floating point context */
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#ifndef CONFIG_M68KFPU_EMU_ONLY
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#ifdef CONFIG_M68KFPU_EMU
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tstl m68k_fputype
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jeq 3f
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#endif
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fsave %a0@(TASK_THREAD+THREAD_FPSTATE)
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#if defined(CONFIG_M68060)
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#if !defined(CPU_M68060_ONLY)
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btst #3,m68k_cputype+3
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beqs 1f
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#endif
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/* The 060 FPU keeps status in bits 15-8 of the first longword */
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tstb %a0@(TASK_THREAD+THREAD_FPSTATE+2)
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jeq 3f
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#if !defined(CPU_M68060_ONLY)
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jra 2f
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#endif
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#endif /* CONFIG_M68060 */
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#if !defined(CPU_M68060_ONLY)
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1: tstb %a0@(TASK_THREAD+THREAD_FPSTATE)
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jeq 3f
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#endif
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2: fmovemx %fp0-%fp7,%a0@(TASK_THREAD+THREAD_FPREG)
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fmoveml %fpcr/%fpsr/%fpiar,%a0@(TASK_THREAD+THREAD_FPCNTL)
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3:
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#endif /* CONFIG_M68KFPU_EMU_ONLY */
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/* Return previous task in %d1 */
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movel %curptr,%d1
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/* switch to new task (a1 contains new task) */
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movel %a1,%curptr
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/* restore floating point context */
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#ifndef CONFIG_M68KFPU_EMU_ONLY
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#ifdef CONFIG_M68KFPU_EMU
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tstl m68k_fputype
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jeq 4f
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#endif
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#if defined(CONFIG_M68060)
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#if !defined(CPU_M68060_ONLY)
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btst #3,m68k_cputype+3
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beqs 1f
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#endif
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/* The 060 FPU keeps status in bits 15-8 of the first longword */
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tstb %a1@(TASK_THREAD+THREAD_FPSTATE+2)
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jeq 3f
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#if !defined(CPU_M68060_ONLY)
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jra 2f
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#endif
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#endif /* CONFIG_M68060 */
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#if !defined(CPU_M68060_ONLY)
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1: tstb %a1@(TASK_THREAD+THREAD_FPSTATE)
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jeq 3f
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#endif
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2: fmovemx %a1@(TASK_THREAD+THREAD_FPREG),%fp0-%fp7
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fmoveml %a1@(TASK_THREAD+THREAD_FPCNTL),%fpcr/%fpsr/%fpiar
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3: frestore %a1@(TASK_THREAD+THREAD_FPSTATE)
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4:
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#endif /* CONFIG_M68KFPU_EMU_ONLY */
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/* restore the kernel stack pointer */
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movel %a1@(TASK_THREAD+THREAD_KSP),%sp
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/* restore non-scratch registers */
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RESTORE_SWITCH_STACK
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/* restore user stack pointer */
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movel %a1@(TASK_THREAD+THREAD_USP),%a0
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movel %a0,%usp
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/* restore fs (sfc,%dfc) */
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movew %a1@(TASK_THREAD+THREAD_FS),%a0
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movec %a0,%sfc
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movec %a0,%dfc
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/* restore status register */
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movew %a1@(TASK_THREAD+THREAD_SR),%sr
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rts
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#endif /* CONFIG_MMU && !CONFIG_COLDFIRE */
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