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comparison dyncallback/dyncall_thunk_mips.c @ 0:3e629dc19168

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initial from svn dyncall-1745
author Daniel Adler
date Thu, 19 Mar 2015 22:24:28 +0100
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children d0787f3b81fb
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-1:000000000000 0:3e629dc19168
1 /*
2
3 Package: dyncall
4 Library: dyncallback
5 File: dyncallback/dyncall_thunk_mips.c
6 Description: Thunk - Implementation for MIPS
7 License:
8
9 Copyright (c) 2013-2015 Daniel Adler <dadler@uni-goettingen.de>,
10 Tassilo Philipp <tphilipp@potion-studios.com>
11
12 Permission to use, copy, modify, and distribute this software for any
13 purpose with or without fee is hereby granted, provided that the above
14 copyright notice and this permission notice appear in all copies.
15
16 THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
17 WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
18 MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
19 ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
20 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
21 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
22 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
23
24 */
25
26 #include "dyncall_thunk.h"
27
28 unsigned short hi16(x) { return ( (unsigned short) (((unsigned int)x)>>16UL) ); }
29 unsigned short lo16(x) { return ( (unsigned short) ((unsigned int)x) ); }
30
31 void dcbInitThunk(DCThunk* p, void (*entry)())
32 {
33 /*
34
35 Thunk Register: $t4 ($12)
36 According to o32abi: $t9
37
38 'The Linux/MIPS convention is that all PIC calls use t9 to hold the address of the called function.'
39 [See MIPS Run, p.413]
40
41 mips thunk code:
42 lui $t4, %hi(p)
43 lui $t9, %hi(entry)
44 ori $t9, $t9, %lo(entry)
45 jr $t9
46 ori $t4, $t4, %lo(p)
47
48 thunk.o: file format elf32-tradbigmips
49
50
51 Disassembly of section .text:
52
53 00000000 <thunk>:
54 0: 3c0c0000 lui t4,0x0
55 4: 3c190000 lui t9,0x0
56 8: 37390000 ori t9,t9,0x0
57 c: 03200008 jr t9
58 10: 00200825 move at,at
59 14: 358c0000 ori t4,t4,0x0
60 18: 00200825 move at,at
61 1c: 00200825 move at,at
62
63 */
64
65 #if defined(DC__Endian_BIG)
66
67 p->data[0] = 0x3c0c; p->data[1] = hi16(p); /* lui $t4, hi(p) */
68 p->data[2] = 0x3c19; p->data[3] = hi16(entry); /* lui $t9, hi(entry) */
69 p->data[4] = 0x3739; p->data[5] = lo16(entry); /* ori $t9, $t9, lo(entry) */
70 p->jump = 0x03200008; /* jr $t9 */
71 p->bddt[0] = 0x358c; p->bddt[1] = lo16(p); /* ori $t4, $t4, lo(p) - branch delay slot */
72
73 #else /* defined(DC__Endian_LITTLE) */
74
75 p->data[1] = 0x3c0c; p->data[0] = hi16(p); /* lui $t4, hi(p) */
76 p->data[3] = 0x3c19; p->data[2] = hi16(entry); /* lui $t9, hi(entry) */
77 p->data[5] = 0x3739; p->data[4] = lo16(entry); /* ori $t9, $t9, lo(entry) */
78 p->jump = 0x03200008; /* jr $t9 */
79 p->bddt[1] = 0x358c; p->bddt[0] = lo16(p); /* ori $t4, $t4, lo(p) - branch delay slot */
80
81 #endif
82
83 }
84