source: src/libcfa/concurrency/CtxSwitch-i386.S @ b13fc10

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Last change on this file since b13fc10 was 7b2c2c5f, checked in by Thierry Delisle <tdelisle@…>, 8 years ago

Fixed saving and loading of control words for i386

  • Property mode set to 100644
File size: 2.8 KB
Line 
1//                               -*- Mode: Asm -*-
2//
3// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
4//
5// The contents of this file are covered under the licence agreement in the
6// file "LICENCE" distributed with Cforall.
7//
8// CtxSwitch-i386.S --
9//
10// Author           : Thierry Delisle
11// Created On       : Tue Dec 6 12:27:26 2016
12// Last Modified By : Thierry Delisle
13// Last Modified On : Tue Dec 6 12:27:26 2016
14// Update Count     : 0
15//
16// This  library is free  software; you  can redistribute  it and/or  modify it
17// under the terms of the GNU Lesser General Public License as published by the
18// Free Software  Foundation; either  version 2.1 of  the License, or  (at your
19// option) any later version.
20//
21// This library is distributed in the  hope that it will be useful, but WITHOUT
22// ANY  WARRANTY;  without even  the  implied  warranty  of MERCHANTABILITY  or
23// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
24// for more details.
25//
26// You should  have received a  copy of the  GNU Lesser General  Public License
27// along  with this library.
28//
29
30// This context switch routine depends on the fact that the stack of a new
31// thread has been set up to look like the thread has saved its context in
32// the normal manner.
33//
34// void CtxSwitch( machine_context *from, machine_context *to );
35
36// Offsets in the context structure. This needs to be synchronized with the
37// high level code a little better.
38
39#define PTR_BYTE        4
40#define SP_OFFSET       ( 0 * PTR_BYTE )
41#define FP_OFFSET       ( 1 * PTR_BYTE )
42#define PC_OFFSET       ( 2 * PTR_BYTE )
43
44.text
45        .align 2
46.globl  CtxSwitch
47CtxSwitch:
48
49        // Copy the "from" context argument from the stack to register eax
50        // Return address is at 0(%esp), with parameters following
51
52        movl 4(%esp),%eax
53
54        // Save floating & SSE control words on the stack.
55
56        sub    $8,%esp
57        stmxcsr 0(%esp)         // 4 bytes
58        fnstcw  4(%esp)         // 2 bytes
59
60        // Save volatile registers on the stack.
61
62        pushl %ebx
63        pushl %edi
64        pushl %esi
65
66        // Save old context in the "from" area.
67
68        movl %esp,SP_OFFSET(%eax)
69        movl %ebp,FP_OFFSET(%eax)
70//      movl 4(%ebp),%ebx       // save previous eip for debugger
71//      movl %ebx,PC_OFFSET(%eax)
72
73        // Copy the "to" context argument from the stack to register eax
74        // Having pushed three words (= 12 bytes) on the stack, the
75        // argument is now at 8 + 12 = 20(%esp)
76
77        movl 28(%esp),%eax
78
79        // Load new context from the "to" area.
80
81        movl SP_OFFSET(%eax),%esp
82        movl FP_OFFSET(%eax),%ebp
83
84        // Load volatile registers from the stack.
85
86        popl %esi
87        popl %edi
88        popl %ebx
89
90        // Load floating & SSE control words from the stack.
91
92        fldcw   4(%esp)
93        ldmxcsr 0(%esp)
94        add    $8,%esp
95
96        // Return to thread.
97
98        ret
99
100.text
101        .align 2
102.globl  CtxGet
103CtxGet:
104        movl %esp,SP_OFFSET(%eax)
105        movl %ebp,FP_OFFSET(%eax)
106
107        ret
108
109// Local Variables: //
110// compile-command: "make install" //
111// End: //
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