1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the Netscape Portable Runtime (NSPR).
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998-2000 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License Version 2 or later (the
* "GPL"), in which case the provisions of the GPL are applicable
* instead of those above. If you wish to allow use of your
* version of this file only under the terms of the GPL and not to
* allow others to use your version of this file under the MPL,
* indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by
* the GPL. If you do not delete the provisions above, a recipient
* may use your version of this file under either the MPL or the
* GPL.
*/
! ======================================================================
!
! Atomically add a new element to the top of the stack
!
! usage : PR_StackPush(listp, elementp);
!
! -----------------------
! Note on REGISTER USAGE:
! as this is a LEAF procedure, a new stack frame is not created.
!
! So, the registers used are:
! %o0 [input] - the address of the stack
! %o1 [input] - the address of the element to be added to the stack
! -----------------------
.section ".text"
.global PR_StackPush
PR_StackPush:
pulock: ld [%o0],%o3 !
cmp %o3,-1 ! check if stack is locked
be pulock ! loop, if locked
mov -1,%o3 ! use delay-slot
swap [%o0],%o3 ! atomically lock the stack and get
! the pointer to stack head
cmp %o3,-1 ! check, if the stack is locked
be pulock ! loop, if so
nop
st %o3,[%o1]
retl ! return back to the caller
st %o1,[%o0] !
.size PR_StackPush,(.-PR_StackPush)
! end
! ======================================================================
! ======================================================================
!
! Atomically remove the element at the top of the stack
!
! usage : elemep = PR_StackPop(listp);
!
! -----------------------
! Note on REGISTER USAGE:
! as this is a LEAF procedure, a new stack frame is not created.
!
! So, the registers used are:
! %o0 [input] - the address of the stack
! %o1 [input] - work register (top element)
! -----------------------
.section ".text"
.global PR_StackPop
PR_StackPop:
polock: ld [%o0],%o1 !
cmp %o1,-1 ! check if stack is locked
be polock ! loop, if locked
mov -1,%o1 ! use delay-slot
swap [%o0],%o1 ! atomically lock the stack and get
! the pointer to stack head
cmp %o1,-1 ! check, if the stack is locked
be polock ! loop, if so
nop
tst %o1 ! test for empty stack
be,a empty ! is empty
st %g0,[%o0]
ld [%o1], %o2 ! load the second element
st %o2,[%o0] ! set stack head to second
st %g0,[%o1] ! reset the next pointer; for
! debugging
empty:
retl ! return back to the caller
mov %o1, %o0 ! return the first element
.size PR_StackPop,(.-PR_StackPop)
! end
! ======================================================================
|
