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56 lines
1.8 KiB
ArmAsm
56 lines
1.8 KiB
ArmAsm
/* Copyright (C) 1991, 1994, 1995 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <sysdep.h>
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#ifndef SYS_vfork
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#define SYS_vfork 66
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#endif
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/* Clone the calling process, but without copying the whole address space.
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The the calling process is suspended until the the new process exits or is
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replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
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and the process ID of the new process to the old process. */
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.globl ___vfork
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___vfork:
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/* Pop the return PC value into A0. */
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moveal sp@+, a0
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/* Stuff the syscall number in D0 and trap into the kernel. */
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movel #SYS_vfork, d0
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trap #0
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bcs error /* Branch forward if it failed. */
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/* It succeeded. See which fork we're in. D1 is now 0 for the
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parent and 1 for the child. Decrement it to make it -1 (all
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bits set) for the parent, and 0 (no bits set) for the child.
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Then AND it with D0, so the parent gets D0&-1==R0, and the child
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gets D0&0==0. */
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subl #1, d1
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andl d1, d0
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/* Jump to the return PC. */
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jmp a0@
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error:
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movel d0, _errno
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moveq #-1, d0
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jmp a0@
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weak_alias (__vfork, vfork)
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