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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 *  | 0x0 | 0x4 | 0x8 | 0xc | 0x10| 0x14| 0x18| 0x1c|  *
14 *  -------------------------------------------------  *
15 *  | s16 | s17 | s18 | s19 | s20 | s21 | s22 | s23 |  *
16 *  -------------------------------------------------  *
17 *  -------------------------------------------------  *
18 *  |  8  |  9  |  10 |  11 |  12 |  13 |  14 |  15 |  *
19 *  -------------------------------------------------  *
20 *  | 0x20| 0x24| 0x28| 0x2c| 0x30| 0x34| 0x38| 0x3c|  *
21 *  -------------------------------------------------  *
22 *  | s24 | s25 | s26 | s27 | s28 | s29 | s30 | s31 |  *
23 *  -------------------------------------------------  *
24 *  -------------------------------------------------  *
25 *  |  16 |  17 |  18 |  19 |  20 |  21 |  22 |  23 |  *
26 *  -------------------------------------------------  *
27 *  | 0x40| 0x44| 0x48| 0x4c| 0x50| 0x54| 0x58| 0x5c|  *
28 *  -------------------------------------------------  *
29 *  |hiddn|  v1 |  v2 |  v3 |  v4 |  v5 |  v6 |  v7 |  *
30 *  -------------------------------------------------  *
31 *  -------------------------------------------------  *
32 *  |  24 |  25 |  26 |  27 |  28 |  29 |  30 |  31 |  *
33 *  -------------------------------------------------  *
34 *  | 0x60| 0x64| 0x68| 0x6c| 0x70| 0x74| 0x78| 0x7c|  *
35 *  -------------------------------------------------  *
36 *  |  v8 |  lr |  pc | FCTX| DATA|                 |  *
37 *  -------------------------------------------------  *
38 *                                                     *
39 *******************************************************/
40
41.file "ontop_arm_aapcs_elf_gas.S"
42.text
43.globl ontop_fcontext
44.align 2
45.type ontop_fcontext,%function
46.syntax unified
47ontop_fcontext:
48    @ save LR as PC
49    push {lr}
50    @ save hidden,V1-V8,LR
51    push {a1,v1-v8,lr}
52
53    @ prepare stack for FPU
54    sub  sp, sp, #64
55#if (defined(__VFP_FP__) && !defined(__SOFTFP__))
56    @ save S16-S31
57    vstmia sp, {d8-d15}
58#endif
59
60    @ store RSP (pointing to context-data) in A1
61    mov  a1, sp
62
63    @ restore RSP (pointing to context-data) from A2
64    mov  sp, a2
65
66    @ store parent context in A2
67    mov  a2, a1
68
69#if (defined(__VFP_FP__) && !defined(__SOFTFP__))
70    @ restore S16-S31
71    vldmia  sp, {d8-d15}
72#endif
73    @ prepare stack for FPU
74    add  sp, sp, #64
75
76    @ restore hidden,V1-V8,LR
77    pop {a1,v1-v8,lr}
78
79    @ return transfer_t from jump
80    str  a2, [a1, #0]
81    str  a3, [a1, #4]
82    @ pass transfer_t as first arg in context function
83    @ A1 == hidden, A2 == FCTX, A3 == DATA
84
85    @ skip PC
86    add  sp, sp, #4
87
88    @ jump to ontop-function
89    bx  a4
90.size ontop_fcontext,.-ontop_fcontext
91
92@ Mark that we don't need executable stack.
93.section .note.GNU-stack,"",%progbits
94