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 *  |    TOC    |    R14    |    R15    |    R16    |  *
16 *  -------------------------------------------------  *
17 *  -------------------------------------------------  *
18 *  |  8  |  9  |  10 |  11 |  12 |  13 |  14 |  15 |  *
19 *  -------------------------------------------------  *
20 *  |  32 |  36 |  40 |  44 |  48 |  52 |  56 |  60 |  *
21 *  -------------------------------------------------  *
22 *  |    R17    |    R18    |     R19   |    R20    |  *
23 *  -------------------------------------------------  *
24 *  -------------------------------------------------  *
25 *  |  16 |  17 |  18 |  19 |  20 |  21 |  22 |  23 |  *
26 *  -------------------------------------------------  *
27 *  |  64 |  68 |  72 |  76 |  80 |  84 |  88 |  92 |  *
28 *  -------------------------------------------------  *
29 *  |    R21    |    R22    |    R23    |    R24    |  *
30 *  -------------------------------------------------  *
31 *  -------------------------------------------------  *
32 *  |  24 |  25 |  26 |  27 |  28 |  29 |  30 |  31 |  *
33 *  -------------------------------------------------  *
34 *  |  96 | 100 | 104 | 108 | 112 | 116 | 120 | 124 |  *
35 *  -------------------------------------------------  *
36 *  |    R25    |    R26    |    R27    |    R28    |  *
37 *  -------------------------------------------------  *
38 *  -------------------------------------------------  *
39 *  |  32 |  33 |  34 |  35 |  36 |  37 |  38 |  39 |  *
40 *  -------------------------------------------------  *
41 *  | 128 | 132 | 136 | 140 | 144 | 148 | 152 | 156 |  *
42 *  -------------------------------------------------  *
43 *  |    R29    |    R30    |    R31    |   hidden  |  *
44 *  -------------------------------------------------  *
45 *  -------------------------------------------------  *
46 *  |  40 |  41 |  42 |  43 |  44 |  45 |  46 |  47 |  *
47 *  -------------------------------------------------  *
48 *  | 160 | 164 | 168 | 172 | 176 | 180 | 184 | 188 |  *
49 *  -------------------------------------------------  *
50 *  |     CR    |     LR    |     PC    | back-chain|  *
51 *  -------------------------------------------------  *
52 *  -------------------------------------------------  *
53 *  |  48 |  49 |  50 |  51 |  52 |  53 |  54 |  55 |  *
54 *  -------------------------------------------------  *
55 *  | 192 | 196 | 200 | 204 | 208 | 212 | 216 | 220 |  *
56 *  -------------------------------------------------  *
57 *  |  cr saved |  lr saved |  compiler |   linker  |  *
58 *  -------------------------------------------------  *
59 *  -------------------------------------------------  *
60 *  |  56 |  57 |  58 |  59 |  60 |  61 |  62 |  63 |  *
61 *  -------------------------------------------------  *
62 *  | 224 | 228 | 232 | 236 | 240 | 244 | 248 | 252 |  *
63 *  -------------------------------------------------  *
64 *  | TOC saved |    FCTX   |    DATA   |           |  *
65 *  -------------------------------------------------  *
66 *                                                     *
67 *******************************************************/
68
69.file "make_ppc64_sysv_elf_gas.S"
70.globl make_fcontext
71#if _CALL_ELF == 2
72	.text
73	.align 2
74make_fcontext:
75	addis	%r2, %r12, .TOC.-make_fcontext@ha
76	addi	%r2, %r2, .TOC.-make_fcontext@l
77	.localentry make_fcontext, . - make_fcontext
78#else
79	.section ".opd","aw"
80	.align 3
81make_fcontext:
82# ifdef _CALL_LINUX
83	.quad	.L.make_fcontext,.TOC.@tocbase,0
84	.type	make_fcontext,@function
85	.text
86	.align 2
87.L.make_fcontext:
88# else
89	.hidden	.make_fcontext
90	.globl	.make_fcontext
91	.quad	.make_fcontext,.TOC.@tocbase,0
92	.size	make_fcontext,24
93	.type	.make_fcontext,@function
94	.text
95	.align 2
96.make_fcontext:
97# endif
98#endif
99    # save return address into R6
100    mflr  %r6
101
102    # first arg of make_fcontext() == top address of context-stack
103    # shift address in R3 to lower 16 byte boundary
104    clrrdi  %r3, %r3, 4
105
106    # reserve space for context-data on context-stack
107    # including 64 byte of linkage + parameter area (R1 % 16 == 0)
108    subi  %r3, %r3, 248
109
110    # third arg of make_fcontext() == address of context-function
111    # entry point (ELFv2) or descriptor (ELFv1)
112#if _CALL_ELF == 2
113    # save address of context-function entry point
114    std  %r5, 176(%r3)
115#else
116    # save address of context-function entry point
117    ld   %r4, 0(%r5)
118    std  %r4, 176(%r3)
119    # save TOC of context-function
120    ld   %r4, 8(%r5)
121    std  %r4, 0(%r3)
122#endif
123
124    # set back-chain to zero
125    li   %r0, 0
126    std  %r0, 184(%r3)
127
128#if _CALL_ELF != 2
129    # zero in r3 indicates first jump to context-function
130    std  %r0, 152(%r3)
131#endif
132
133    # load LR
134    mflr  %r0
135    # jump to label 1
136    bl  1f
1371:
138    # load LR into R4
139    mflr  %r4
140    # compute abs address of label finish
141    addi  %r4, %r4, finish - 1b
142    # restore LR
143    mtlr  %r0
144    # save address of finish as return-address for context-function
145    # will be entered after context-function returns
146    std  %r4, 168(%r3)
147
148    # restore return address from R6
149    mtlr  %r6
150
151    blr  # return pointer to context-data
152
153finish:
154    # save return address into R0
155    mflr  %r0
156    # save return address on stack, set up stack frame
157    std  %r0, 8(%r1)
158    # allocate stack space, R1 % 16 == 0
159    stdu  %r1, -32(%r1)
160
161    # exit code is zero
162    li  %r3, 0
163    # exit application
164    bl  _exit
165    nop
166#if _CALL_ELF == 2
167	.size make_fcontext, .-make_fcontext
168#else
169# ifdef _CALL_LINUX
170	.size .make_fcontext, .-.L.make_fcontext
171# else
172	.size .make_fcontext, .-.make_fcontext
173# endif
174#endif
175
176/* Mark that we don't need executable stack.  */
177.section .note.GNU-stack,"",%progbits
178