1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
|
/* Copyright (c) 2012-2015 Red Hat, Inc. All rights reserved.
This copyrighted material is made available to anyone wishing to use, modify,
copy, or redistribute it subject to the terms and conditions of the BSD
License. This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY expressed or implied, including the implied warranties
of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. A copy of this license
is available at http://www.opensource.org/licenses. Any Red Hat trademarks that
are incorporated in the source code or documentation are not subject to the BSD
License and may only be used or replicated with the express permission of
Red Hat, Inc.
*/
#include "memmodel.h"
;; The linker links all .crt_* sections in asciibetical order at the
;; same place. So, the four digits in .crt_NNNN_xxx name created by
;; the START_CRT_FUNC macro determine the link order, so, keep them
;; in sequential order here. The first two digits are set here, the
;; second two allow users to insert code between code fragments here.
#if L0
.section ".resetvec", "a"
__msp430_resetvec_hook:
.word __crt0_start
;; Here we provide weak definitions of the symbols used in the
;; init_highbss and move_highdata blocks, in case they are not
;; provided by the linker script. They are defined here because
;; this block is always included in every executable, and because
;; if there were defined in the blocks that need them their values
;; would be used without giving the linker script a chance to
;; override them.
;;
;; The weak definitions are needed if the user targets an MCU
;; without high memory - and hence uses a linker script without
;; a definition of the .upper.bss or .upper.data sections - and
;; they have compiled their code with the -mdata-region=either
;; command line option. That option causes the assembler to
;; define the __crt0_move_highdata and/or crt0_init_highbss
;; symbols, which in turn forces the inclusion of the
;; move_highdata and/or init_highbss blocks in the startup code,
;; regardless of the fact that the sections are not present in
;; the linker script.
WEAK_DEF __upper_data_init
WEAK_DEF __rom_highdatacopysize
WEAK_DEF __high_datastart
WEAK_DEF __rom_highdatastart
WEAK_DEF __high_bssstart
WEAK_DEF __high_bsssize
START_CRT_FUNC 0000 start
.refsym __msp430_resetvec_hook
.refsym __crt0_call_main
mov_ #__stack, R1
END_CRT_FUNC start
#endif
;; The CRT functions below will only be present in the final linked
;; executable if the assembler decides they are needed. The assembler will
;; only define the symbol necessary to prevent them being garbage collected
;; by the linker if the file being assembled has a specific section,
;; or some other criteria is met.
;; The exception to this is __crt0_call_exit. GCC will include this function
;; if it detects that main() has an epilogue. For example, if main() has a
;; while(1) loop at the end, GCC will not generate an epilogue (since it won't
;; return) and __crt0_call_exit won't be included.
#if Lbss
;; This function is responsible for initializing the contents of the
;; .bss section.
START_CRT_FUNC 0100 init_bss
mov_ #__bssstart, R12
clr.w R13
mov_ #__bsssize, R14
#ifdef __MSP430X_LARGE__
clr.w R15 ; We assume that __bsssize is never > 64K
#endif
call_ #memset
END_CRT_FUNC init_bss
#endif /* Lbss */
#ifdef __MSP430X_LARGE__
#if Lhigh_bss
;; This function is responsible for initializing the contents of the
;; .upper.bss section.
START_CRT_FUNC 0200 init_highbss
mov_ #__high_bssstart, R12
mov.w #0, R13
mov_ #__high_bsssize, R14
;; If __high_bsssize is zero then skip the call to memset.
;; This can happen if all of the bss data was placed into .either.bss.
cmp.w #0, R14
jeq 1f
call_ #memset
1:
END_CRT_FUNC init_highbss
#endif /* Lhigh_bss */
#endif /* __MSP430X_LARGE__ */
#if Lmovedata
;; This function is responsible for copying the
;; contents of the .data section from its load address (in ROM) to
;; its run-time address (in RAM).
START_CRT_FUNC 0300 movedata
mov_ #__datastart, R12
mov_ #__romdatastart, R13
;; memmove and memcpy do not currently work when src == dst
cmp_ R12, R13
jeq 1f
mov_ #__romdatacopysize, R14
call_ #memmove
1:
END_CRT_FUNC movedata
#endif /* Lmovedata */
#ifdef __MSP430X_LARGE__
#if Lmove_highdata
;; This function is responsible for making sure that the
;; contents of the .upper.data section have their correct startup values.
;; If a copy of the .upper.data section is stored in ROM then this means
;; copying the contents into HIFRAM. If a copy of .upper.data is stored in a
;; shadow section in HIFRAM then this means copying from the shadow section
;; into the real section.
START_CRT_FUNC 0400 move_highdata
;; __rom_highdatacopysize may be zero. Test this first because
;; its value may come from the weak definitions above and we do
;; not want to access the memory at address 0 pointed to by the
;; weak definition of __upper_data_init.
mov.w #__rom_highdatacopysize, R14
cmp.w #0, R14
jeq 3f
/* Test our status word. */
cmpx.w #0, &__upper_data_init
jeq 1f
/* Status word is non-zero - copy from shadow into upper. */
mov_ #__high_datastart, R12
mov_ #__rom_highdatastart, R13
jmp 2f
1: /* Status word is zero. Copy from upper to shadow and change status word. */
movx.w #1, &__upper_data_init
mov_ #__rom_highdatastart, R12
mov_ #__high_datastart, R13
2: ;; __rom_highdatacopysize may be zero. memmove should cope.
mov.w #__rom_highdatacopysize, R14
call_ #memmove
3:
END_CRT_FUNC move_highdata
#endif /* Lmove_highdata */
#endif /* __MSP430X_LARGE__ */
#if Lrun_preinit_array
;; This function is responsible for setting up the arguments
;; required for __crt0_run_array, to run the functions in .preinit_array.
START_CRT_FUNC 0500 run_preinit_array
mov_ #__preinit_array_start, R4
mov_ #__preinit_array_end, R5
mov_ #PTRsz, R6
call_ #__crt0_run_array
END_CRT_FUNC run_preinit_array
#endif /* Lrun_preinit_array */
#if Lrun_init_array
;; This function is responsible for setting up the arguments
;; required for __crt0_run_array, to run the functions in .init_array.
START_CRT_FUNC 0600 run_init_array
mov_ #__init_array_start, R4
mov_ #__init_array_end, R5
mov_ #PTRsz, R6
call_ #__crt0_run_array
END_CRT_FUNC run_init_array
#endif /* Lrun_init_array */
#if Lmain
;; This function is always included and calls main().
START_CRT_FUNC 0800 call_main
clr.w R12 ; Set argc == 0
call_ #main
END_CRT_FUNC call_main
#endif /* Lmain */
#if Lcallexit
;; This function is responsible for calling exit once main has finished.
START_CRT_FUNC 0900 call_exit
call_ #_exit
END_CRT_FUNC call_exit
#endif /* Lcallexit */
;----------------------------------------
#if Lrun_fini_array
;; This function is responsible for setting up the arguments
;; required for __crt0_run_array, to run the functions in .fini_array.
START_CRT_FUNC 1000 run_fini_array
mov_ #__fini_array_start, R4
mov_ #__fini_array_end, R5
mov_ #-PTRsz, R6
call_ #__crt0_run_array
END_CRT_FUNC run_fini_array
#endif /* Lrun_fini_array */
#if Lrun_array
;; Note - this section is only included in the startup code of the application
;; if it is needed by one of the above run_*_array functions.
START_CRT_FUNC 1100 run_array
cmp_ R4, R5
jeq _msp430_run_done
mov_ @R4, R7
add_ R6, R4
call_ R7
br_ #__crt0_run_array
END_CRT_FUNC run_array
_msp430_run_done:
ret_
#endif /* Lrun_array */
|
