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101 lines
3.1 KiB
ArmAsm
101 lines
3.1 KiB
ArmAsm
/* Create new context.
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Copyright (C) 2012-2014 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 Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the 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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include "ucontext_i.h"
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ENTRY(__makecontext)
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move.l 4(%sp), %a0
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/* Get the address of the function we are supposed to run. */
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move.l 8(%sp), oPC(%a0)
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/* Compute the address of the stack. The information comes from
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to us_stack element. */
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move.l oSS_SP(%a0), %a1
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add.l oSS_SIZE(%a0), %a1
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/* Remember the number of parameters for the exit handler since
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it has to remove them. We store the number in the D7 register
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which the function we will call must preserve. */
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move.l 12(%sp), %d1
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move.l %d1, oGREGS+7*4(%a0)
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/* Make room on the new stack for the parameters.
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Room for the arguments, return address (== 1f) and
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oLINK pointer is needed. */
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neg.l %d1
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lea -8(%a1,%d1.l*4), %a1
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neg.l %d1
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/* Store the future stack pointer. */
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move.l %a1, oSP(%a0)
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/* Put the next context on the new stack (from the uc_link
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element). */
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move.l oLINK(%a0), 4(%a1,%d1.l*4)
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/* Copy all the parameters. */
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1: subq.l #1,%d1
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jmi 2f
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move.l 16(%sp,%d1.l*4), 4(%a1,%d1.l*4)
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jra 1b
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2:
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/* If the function we call returns we must continue with the
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context which is given in the uc_link element. To do this
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set the return address for the function the user provides
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to a little bit of helper code which does the magic (see
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below). */
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lea 1f(%pc), %a0
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move.l %a0, (%a1)
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/* 'makecontext' returns no value. */
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rts
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/* This is the helper code which gets called if a function which
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is registered with 'makecontext' returns. In this case we
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have to install the context listed in the uc_link element of
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the context 'makecontext' manipulated at the time of the
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'makecontext' call. If the pointer is NULL the process must
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terminate. */
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cfi_endproc
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1:
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/* This removes the parameters passed to the function given to
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'makecontext' from the stack. D7 contains the number of
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parameters (see above). */
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lea (%sp,%d7.l*4), %sp
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tst.l (%sp) /* Check the next context. */
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jeq 2f /* If it is zero exit. */
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jbsr JUMPTARGET(__setcontext)
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/* If this returns (which can happen if the syscall fails) we'll
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exit the program with the return error value (-1). */
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move.l %d0, (%sp)
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2: jbsr HIDDEN_JUMPTARGET(exit)
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/* The 'exit' call should never return. In case it does cause
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the process to terminate. */
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illegal
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cfi_startproc
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END(__makecontext)
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weak_alias (__makecontext, makecontext)
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