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[thirdparty/glibc.git] / sysdeps / unix / sysv / linux / i386 / setcontext.S
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4ee87ecc 1/* Install given context.
a334319f 2 Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
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3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@redhat.com>, 2001.
5
6 The GNU C Library is free software; you can redistribute it and/or
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7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
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10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
41bdb6e2 14 Lesser General Public License for more details.
4ee87ecc 15
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16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
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20
21#include <sysdep.h>
22
23#include "ucontext_i.h"
24
25
26ENTRY(__setcontext)
27 /* Load address of the context data structure. */
28 movl 4(%esp), %eax
29
30 /* Get the current signal mask. Note that we preserve EBX in case
31 the system call fails and we return from the function with an
32 error. */
33 pushl %ebx
34 xorl %edx, %edx
35 leal oSIGMASK(%eax), %ecx
36 movl $SIG_SETMASK, %ebx
37 movl $__NR_sigprocmask, %eax
097eca29 38 ENTER_KERNEL
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39 popl %ebx
40 cmpl $-4095, %eax /* Check %eax for error. */
41 jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */
42
43 /* EAX was modified, reload it. */
44 movl 4(%esp), %eax
45
46 /* Restore the floating-point context. Not the registers, only the
47 rest. */
48 movl oFPREGS(%eax), %ecx
49 fldenv (%ecx)
50
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51 /* Restore the FS segment register. We don't touch the GS register
52 since it is used for threads. */
4ee87ecc 53 movl oFS(%eax), %ecx
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54 movw %cx, %fs
55
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56 /* Fetch the address to return to. */
57 movl oEIP(%eax), %ecx
58
4ee87ecc 59 /* Load the new stack pointer. */
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60 movl oESP(%eax), %esp
61
62 /* Push the return address on the new stack so we can return there. */
63 pushl %ecx
64
65 /* Load the values of all the 32-bit registers (except ESP).
66 Since we are loading from EAX, it must be last. */
67 movl oEDI(%eax), %edi
68 movl oESI(%eax), %esi
69 movl oEBP(%eax), %ebp
70 movl oEBX(%eax), %ebx
71 movl oEDX(%eax), %edx
72 movl oECX(%eax), %ecx
73 movl oEAX(%eax), %eax
74
75 /* The following 'ret' will pop the address of the code and jump
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76 to it. */
77
78L(pseudo_end):
79 ret
80PSEUDO_END(__setcontext)
81
a334319f 82weak_alias(__setcontext, setcontext)