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0a595803 AS |
1 | /* Motorola m68k target-dependent support for GNU/Linux. |
2 | ||
d0b45d99 | 3 | Copyright 1996, 1998, 2000, 2001, 2002, 2003 Free Software Foundation, |
0a595803 AS |
4 | Inc. |
5 | ||
6 | This file is part of GDB. | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program; if not, write to the Free Software | |
20 | Foundation, Inc., 59 Temple Place - Suite 330, | |
21 | Boston, MA 02111-1307, USA. */ | |
22 | ||
23 | #include "defs.h" | |
24 | #include "gdbcore.h" | |
25 | #include "frame.h" | |
26 | #include "target.h" | |
d0b45d99 AS |
27 | #include "gdb_string.h" |
28 | #include "gdbtypes.h" | |
29 | #include "m68k-tdep.h" | |
0a595803 AS |
30 | \f |
31 | /* Check whether insn1 and insn2 are parts of a signal trampoline. */ | |
32 | ||
33 | #define IS_SIGTRAMP(insn1, insn2) \ | |
34 | (/* addaw #20,sp; moveq #119,d0; trap #0 */ \ | |
35 | (insn1 == 0xdefc0014 && insn2 == 0x70774e40) \ | |
36 | /* moveq #119,d0; trap #0 */ \ | |
37 | || insn1 == 0x70774e40) | |
38 | ||
39 | #define IS_RT_SIGTRAMP(insn1, insn2) \ | |
40 | (/* movel #173,d0; trap #0 */ \ | |
41 | (insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \ | |
42 | /* moveq #82,d0; notb d0; trap #0 */ \ | |
43 | || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40)) | |
44 | ||
45 | /* Return non-zero if PC points into the signal trampoline. For the sake | |
46 | of m68k_linux_frame_saved_pc we also distinguish between non-RT and RT | |
47 | signal trampolines. */ | |
48 | ||
49 | int | |
50 | m68k_linux_in_sigtramp (CORE_ADDR pc) | |
51 | { | |
52 | CORE_ADDR sp; | |
53 | char buf[12]; | |
54 | unsigned long insn0, insn1, insn2; | |
55 | ||
56 | if (read_memory_nobpt (pc - 4, buf, sizeof (buf))) | |
57 | return 0; | |
58 | insn1 = extract_unsigned_integer (buf + 4, 4); | |
59 | insn2 = extract_unsigned_integer (buf + 8, 4); | |
60 | if (IS_SIGTRAMP (insn1, insn2)) | |
61 | return 1; | |
62 | if (IS_RT_SIGTRAMP (insn1, insn2)) | |
63 | return 2; | |
64 | ||
65 | insn0 = extract_unsigned_integer (buf, 4); | |
66 | if (IS_SIGTRAMP (insn0, insn1)) | |
67 | return 1; | |
68 | if (IS_RT_SIGTRAMP (insn0, insn1)) | |
69 | return 2; | |
70 | ||
71 | insn0 = (insn0 << 16) | (insn1 >> 16); | |
72 | insn1 = (insn1 << 16) | (insn2 >> 16); | |
73 | if (IS_SIGTRAMP (insn0, insn1)) | |
74 | return 1; | |
75 | if (IS_RT_SIGTRAMP (insn0, insn1)) | |
76 | return 2; | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */ | |
82 | #define SIGCONTEXT_PC_OFFSET 26 | |
83 | ||
84 | /* Offset to saved PC in ucontext, from <asm/ucontext.h>. */ | |
85 | #define UCONTEXT_PC_OFFSET 88 | |
86 | ||
87 | /* Get saved user PC for sigtramp from sigcontext or ucontext. */ | |
88 | ||
89 | static CORE_ADDR | |
90 | m68k_linux_sigtramp_saved_pc (struct frame_info *frame) | |
91 | { | |
92 | CORE_ADDR sigcontext_addr; | |
93 | char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT]; | |
94 | int ptrbytes = TARGET_PTR_BIT / TARGET_CHAR_BIT; | |
95 | int sigcontext_offs = (2 * TARGET_INT_BIT) / TARGET_CHAR_BIT; | |
96 | ||
97 | /* Get sigcontext address, it is the third parameter on the stack. */ | |
d0b45d99 | 98 | if (get_next_frame (frame)) |
b5fc49aa | 99 | sigcontext_addr |
d0b45d99 | 100 | = read_memory_unsigned_integer (get_frame_base (get_next_frame (frame)) |
b5fc49aa AS |
101 | + FRAME_ARGS_SKIP |
102 | + sigcontext_offs, | |
103 | ptrbytes); | |
0a595803 | 104 | else |
b5fc49aa AS |
105 | sigcontext_addr |
106 | = read_memory_unsigned_integer (read_register (SP_REGNUM) | |
107 | + sigcontext_offs, | |
108 | ptrbytes); | |
0a595803 AS |
109 | |
110 | /* Don't cause a memory_error when accessing sigcontext in case the | |
111 | stack layout has changed or the stack is corrupt. */ | |
d0b45d99 | 112 | if (m68k_linux_in_sigtramp (get_frame_pc (frame)) == 2) |
0a595803 AS |
113 | target_read_memory (sigcontext_addr + UCONTEXT_PC_OFFSET, buf, ptrbytes); |
114 | else | |
115 | target_read_memory (sigcontext_addr + SIGCONTEXT_PC_OFFSET, buf, ptrbytes); | |
116 | return extract_unsigned_integer (buf, ptrbytes); | |
117 | } | |
118 | ||
119 | /* Return the saved program counter for FRAME. */ | |
120 | ||
121 | CORE_ADDR | |
122 | m68k_linux_frame_saved_pc (struct frame_info *frame) | |
123 | { | |
124 | if (get_frame_type (frame) == SIGTRAMP_FRAME) | |
125 | return m68k_linux_sigtramp_saved_pc (frame); | |
126 | ||
d0b45d99 AS |
127 | return read_memory_unsigned_integer (get_frame_base (frame) + 4, 4); |
128 | } | |
129 | ||
130 | void | |
131 | m68k_linux_extract_return_value (struct type *type, char *regbuf, char *valbuf) | |
132 | { | |
133 | if (TYPE_CODE (type) == TYPE_CODE_FLT) | |
134 | { | |
135 | REGISTER_CONVERT_TO_VIRTUAL (FP0_REGNUM, type, | |
136 | regbuf + REGISTER_BYTE (FP0_REGNUM), | |
137 | valbuf); | |
138 | } | |
139 | else if (TYPE_CODE (type) == TYPE_CODE_PTR) | |
140 | memcpy (valbuf, regbuf + REGISTER_BYTE (M68K_A0_REGNUM), | |
141 | TYPE_LENGTH (type)); | |
142 | else | |
143 | memcpy (valbuf, | |
144 | regbuf + (TYPE_LENGTH (type) >= 4 ? 0 : 4 - TYPE_LENGTH (type)), | |
145 | TYPE_LENGTH (type)); | |
146 | } | |
147 | ||
148 | void | |
149 | m68k_linux_store_return_value (struct type *type, char *valbuf) | |
150 | { | |
151 | if (TYPE_CODE (type) == TYPE_CODE_FLT) | |
152 | { | |
153 | char raw_buffer[REGISTER_RAW_SIZE (FP0_REGNUM)]; | |
154 | REGISTER_CONVERT_TO_RAW (type, FP0_REGNUM, valbuf, raw_buffer); | |
155 | deprecated_write_register_bytes (REGISTER_BYTE (FP0_REGNUM), | |
156 | raw_buffer, TYPE_LENGTH (type)); | |
157 | } | |
158 | else | |
159 | { | |
160 | if (TYPE_CODE (type) == TYPE_CODE_PTR) | |
161 | deprecated_write_register_bytes (REGISTER_BYTE (M68K_A0_REGNUM), | |
162 | valbuf, TYPE_LENGTH (type)); | |
163 | deprecated_write_register_bytes (0, valbuf, TYPE_LENGTH (type)); | |
164 | } | |
165 | } | |
166 | ||
167 | CORE_ADDR | |
168 | m68k_linux_extract_struct_value_address (char *regbuf) | |
169 | { | |
170 | return *(CORE_ADDR *) (regbuf + REGISTER_BYTE (M68K_A0_REGNUM)); | |
0a595803 | 171 | } |