1/*
2            Copyright Oliver Kowalke 2009.
3   Distributed under the Boost Software License, Version 1.0.
4      (See accompanying file LICENSE_1_0.txt or copy at
5          http://www.boost.org/LICENSE_1_0.txt)
6*/
7
8/*******************************************************
9 *                                                     *
10 *  -------------------------------------------------  *
11 *  |  0  |  1  |  2  |  3  |  4  |  5  |  6  |  7  |  *
12 *  -------------------------------------------------  *
13 *  |  0  |  4  |  8  |  12 |  16 |  20 |  24 |  28 |  *
14 *  -------------------------------------------------  *
15 *  |    F14    |    F15    |    F16    |    F17    |  *
16 *  -------------------------------------------------  *
17 *  -------------------------------------------------  *
18 *  |  8  |  9  |  10 |  11 |  12 |  13 |  14 |  15 |  *
19 *  -------------------------------------------------  *
20 *  |  32 |  36 |  40 |  44 |  48 |  52 |  56 |  60 |  *
21 *  -------------------------------------------------  *
22 *  |    F18    |    F19    |    F20    |    F21    |  *
23 *  -------------------------------------------------  *
24 *  -------------------------------------------------  *
25 *  |  16 |  17 |  18 |  19 |  20 |  21 |  22 |  23 |  *
26 *  -------------------------------------------------  *
27 *  |  64 |  68 |  72 |  76 |  80 |  84 |  88 |  92 |  *
28 *  -------------------------------------------------  *
29 *  |    F22    |    F23    |    F24    |    F25    |  *
30 *  -------------------------------------------------  *
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32 *  |  24 |  25 |  26 |  27 |  28 |  29 |  30 |  31 |  *
33 *  -------------------------------------------------  *
34 *  |  96 | 100 | 104 | 108 | 112 | 116 | 120 | 124 |  *
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36 *  |    F26    |    F27    |    F28    |    F29    |  *
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38 *  -------------------------------------------------  *
39 *  |  32 |  33 |  34 |  35 |  36 |  37 |  38 |  39 |  *
40 *  -------------------------------------------------  *
41 *  | 128 | 132 | 136 | 140 | 144 | 148 | 152 | 156 |  *
42 *  -------------------------------------------------  *
43 *  |    F30    |    F31    |   fpscr   |    TOC    |  *
44 *  -------------------------------------------------  *
45 *  -------------------------------------------------  *
46 *  |  40 |  41 |  42 |  43 |  44 |  45 |  46 |  47 |  *
47 *  -------------------------------------------------  *
48 *  | 160 | 164 | 168 | 172 | 176 | 180 | 184 | 188 |  *
49 *  -------------------------------------------------  *
50 *  |    R14    |    R15    |     R16   |    R17    |  *
51 *  -------------------------------------------------  *
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53 *  |  48 |  49 |  50 |  51 |  52 |  53 |  54 |  55 |  *
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55 *  | 192 | 196 | 200 | 204 | 208 | 212 | 216 | 220 |  *
56 *  -------------------------------------------------  *
57 *  |    R18    |    R19    |    R20    |    R21    |  *
58 *  -------------------------------------------------  *
59 *  -------------------------------------------------  *
60 *  |  56 |  57 |  58 |  59 |  60 |  61 |  62 |  63 |  *
61 *  -------------------------------------------------  *
62 *  | 224 | 228 | 232 | 236 | 240 | 244 | 248 | 252 |  *
63 *  -------------------------------------------------  *
64 *  |    R22    |    R23    |    R24    |    R25    |  *
65 *  -------------------------------------------------  *
66 *  -------------------------------------------------  *
67 *  |  64 |  65 |  66 |  67 |  68 |  69 |  70 |  71 |  *
68 *  -------------------------------------------------  *
69 *  | 256 | 260 | 264 | 268 | 272 | 276 | 280 | 284 |  *
70 *  -------------------------------------------------  *
71 *  |    R26    |    R27    |    R28    |    R29    |  *
72 *  -------------------------------------------------  *
73 *  -------------------------------------------------  *
74 *  |  72 |  73 |  74 |  75 |  76 |  77 |  78 |  79 |  *
75 *  -------------------------------------------------  *
76 *  | 288 | 292 | 296 | 300 | 304 | 308 | 312 | 316 |  *
77 *  -------------------------------------------------  *
78 *  -------------------------------------------------  *
79 *  |    R30    |    R31    |     CR    |     LR    |  *
80 *  -------------------------------------------------  *
81 *  -------------------------------------------------  *
82 *  |  80 |  81 |                                   |  *
83 *  -------------------------------------------------  *
84 *  | 320 | 324 |                                   |  *
85 *  -------------------------------------------------  *
86 *  |    PC     |                                   |  *
87 *  -------------------------------------------------  *
88 *                                                     *
89 *******************************************************/
90
91.globl make_fcontext
92#if _CALL_ELF == 2
93	.text
94	.align 2
95make_fcontext:
96	addis	%r2, %r12, .TOC.-make_fcontext@ha
97	addi	%r2, %r2, .TOC.-make_fcontext@l
98	.localentry make_fcontext, . - make_fcontext
99#else
100	.section ".opd","aw"
101	.align 3
102make_fcontext:
103# ifdef _CALL_LINUX
104	.quad	.L.make_fcontext,.TOC.@tocbase,0
105	.type	make_fcontext,@function
106	.text
107	.align 2
108.L.make_fcontext:
109# else
110	.hidden	.make_fcontext
111	.globl	.make_fcontext
112	.quad	.make_fcontext,.TOC.@tocbase,0
113	.size	make_fcontext,24
114	.type	.make_fcontext,@function
115	.text
116	.align 2
117.make_fcontext:
118# endif
119#endif
120    # save return address into R6
121    mflr  %r6
122
123    # first arg of make_fcontext() == top address of context-stack
124    # shift address in R3 to lower 16 byte boundary
125    clrrdi  %r3, %r3, 4
126
127    # reserve space for context-data on context-stack
128    # including 64 byte of linkage + parameter area (R1 % 16 == 0)
129    subi  %r3, %r3, 392
130
131    # third arg of make_fcontext() == address of context-function
132    # entry point (ELFv2) or descriptor (ELFv1)
133#if _CALL_ELF == 2
134    # save address of context-function entry point
135    std  %r5, 320(%r3)
136#else
137    # save address of context-function entry point
138    ld   %r4, 0(%r5)
139    std  %r4, 320(%r3)
140    # save TOC of context-function
141    ld   %r4, 8(%r5)
142    std  %r4, 152(%r3)
143#endif
144
145    # load LR
146    mflr  %r0
147    # jump to label 1
148    bl  1f
1491:
150    # load LR into R4
151    mflr  %r4
152    # compute abs address of label finish
153    addi  %r4, %r4, finish - 1b
154    # restore LR
155    mtlr  %r0
156    # save address of finish as return-address for context-function
157    # will be entered after context-function returns
158    std  %r4, 312(%r3)
159
160    # restore return address from R6
161    mtlr  %r6
162
163    blr  # return pointer to context-data
164
165finish:
166    # save return address into R0
167    mflr  %r0
168    # save return address on stack, set up stack frame
169    std  %r0, 8(%r1)
170    # allocate stack space, R1 % 16 == 0
171    stdu  %r1, -32(%r1)
172
173    # exit code is zero
174    li  %r3, 0
175    # exit application
176    bl  _exit
177    nop
178#if _CALL_ELF == 2
179	.size make_fcontext, .-make_fcontext
180#else
181# ifdef _CALL_LINUX
182	.size .make_fcontext, .-.L.make_fcontext
183# else
184	.size .make_fcontext, .-.make_fcontext
185# endif
186#endif
187
188/* Mark that we don't need executable stack.  */
189.section .note.GNU-stack,"",%progbits
190