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
252
|
/*
* Copyright (c) 2006-2022, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2013-07-05 Bernard the first version
*/
.equ Mode_USR, 0x10
.equ Mode_FIQ, 0x11
.equ Mode_IRQ, 0x12
.equ Mode_SVC, 0x13
.equ Mode_ABT, 0x17
.equ Mode_UND, 0x1B
.equ Mode_SYS, 0x1F
.equ I_Bit, 0x80 @ when I bit is set, IRQ is disabled
.equ F_Bit, 0x40 @ when F bit is set, FIQ is disabled
.equ UND_Stack_Size, 0x00000200
.equ SVC_Stack_Size, 0x00000100
.equ ABT_Stack_Size, 0x00000000
.equ FIQ_Stack_Size, 0x00000000
.equ IRQ_Stack_Size, 0x00000100
.equ USR_Stack_Size, 0x00000100
#define ISR_Stack_Size (UND_Stack_Size + SVC_Stack_Size + ABT_Stack_Size + \
FIQ_Stack_Size + IRQ_Stack_Size)
/* stack */
.globl stack_start
.globl stack_top
.align 3
stack_start:
.rept ISR_Stack_Size
.long 0
.endr
stack_top:
/* reset entry */
.globl _reset
_reset:
/* set the cpu to SVC32 mode and disable interrupt */
mrs r0, cpsr
bic r0, r0, #0x1f
orr r0, r0, #0x13
msr cpsr_c, r0
/* setup stack */
bl stack_setup
/* clear .bss */
mov r0,#0 /* get a zero */
ldr r1,=__bss_start /* bss start */
ldr r2,=__bss_end /* bss end */
bss_loop:
cmp r1,r2 /* check if data to clear */
strlo r0,[r1],#4 /* clear 4 bytes */
blo bss_loop /* loop until done */
/* call C++ constructors of global objects */
ldr r0, =__ctors_start__
ldr r1, =__ctors_end__
ctor_loop:
cmp r0, r1
beq ctor_end
ldr r2, [r0], #4
stmfd sp!, {r0-r1}
mov lr, pc
bx r2
ldmfd sp!, {r0-r1}
b ctor_loop
ctor_end:
/* start RT-Thread Kernel */
ldr pc, _rtthread_startup
_rtthread_startup:
.word rtthread_startup
stack_setup:
ldr r0, =stack_top
@ Enter Undefined Instruction Mode and set its Stack Pointer
msr cpsr_c, #Mode_UND|I_Bit|F_Bit
mov sp, r0
sub r0, r0, #UND_Stack_Size
@ Enter Abort Mode and set its Stack Pointer
msr cpsr_c, #Mode_ABT|I_Bit|F_Bit
mov sp, r0
sub r0, r0, #ABT_Stack_Size
@ Enter FIQ Mode and set its Stack Pointer
msr cpsr_c, #Mode_FIQ|I_Bit|F_Bit
mov sp, r0
sub r0, r0, #FIQ_Stack_Size
@ Enter IRQ Mode and set its Stack Pointer
msr cpsr_c, #Mode_IRQ|I_Bit|F_Bit
mov sp, r0
sub r0, r0, #IRQ_Stack_Size
@ Enter Supervisor Mode and set its Stack Pointer
msr cpsr_c, #Mode_SVC|I_Bit|F_Bit
mov sp, r0
sub r0, r0, #SVC_Stack_Size
@ Enter User Mode and set its Stack Pointer
mov sp, r0
sub sl, sp, #USR_Stack_Size
bx lr
/* exception handlers: undef, swi, padt, dabt, resv, irq, fiq */
.align 5
.globl vector_undef
vector_undef:
sub sp, sp, #72
stmia sp, {r0 - r12} @/* Calling r0-r12 */
add r8, sp, #60
mrs r1, cpsr
mrs r2, spsr
orr r2,r2, #I_Bit|F_Bit
msr cpsr_c, r2
mov r0, r0
stmdb r8, {sp, lr} @/* Calling SP, LR */
msr cpsr_c, r1 @/* return to Undefined Instruction mode */
str lr, [r8, #0] @/* Save calling PC */
mrs r6, spsr
str r6, [r8, #4] @/* Save CPSR */
str r0, [r8, #8] @/* Save OLD_R0 */
mov r0, sp
bl rt_hw_trap_udef
ldmia sp, {r0 - r12} @/* Calling r0 - r2 */
mov r0, r0
ldr lr, [sp, #60] @/* Get PC */
add sp, sp, #72
movs pc, lr @/* return & move spsr_svc into cpsr */
.align 5
.globl vector_swi
vector_swi:
bl rt_hw_trap_swi
.align 5
.globl vector_pabt
vector_pabt:
bl rt_hw_trap_pabt
.align 5
.globl vector_dabt
vector_dabt:
sub sp, sp, #72
stmia sp, {r0 - r12} @/* Calling r0-r12 */
add r8, sp, #60
stmdb r8, {sp, lr} @/* Calling SP, LR */
str lr, [r8, #0] @/* Save calling PC */
mrs r6, spsr
str r6, [r8, #4] @/* Save CPSR */
str r0, [r8, #8] @/* Save OLD_R0 */
mov r0, sp
bl rt_hw_trap_dabt
ldmia sp, {r0 - r12} @/* Calling r0 - r2 */
mov r0, r0
ldr lr, [sp, #60] @/* Get PC */
add sp, sp, #72
movs pc, lr @/* return & move spsr_svc into cpsr */
.align 5
.globl vector_resv
vector_resv:
b .
.align 5
.globl vector_fiq
vector_fiq:
stmfd sp!,{r0-r7,lr}
bl rt_hw_trap_fiq
ldmfd sp!,{r0-r7,lr}
subs pc,lr,#4
.globl rt_interrupt_enter
.globl rt_interrupt_leave
.globl rt_thread_switch_interrupt_flag
.globl rt_interrupt_from_thread
.globl rt_interrupt_to_thread
.globl rt_current_thread
.globl vmm_thread
.globl vmm_virq_check
.globl vector_irq
vector_irq:
stmfd sp!, {r0-r12,lr}
bl rt_interrupt_enter
bl rt_hw_trap_irq
bl rt_interrupt_leave
@ if rt_thread_switch_interrupt_flag set, jump to
@ rt_hw_context_switch_interrupt_do and don't return
ldr r0, =rt_thread_switch_interrupt_flag
ldr r1, [r0]
cmp r1, #1
beq rt_hw_context_switch_interrupt_do
ldmfd sp!, {r0-r12,lr}
subs pc, lr, #4
rt_hw_context_switch_interrupt_do:
mov r1, #0 @ clear flag
str r1, [r0]
ldmfd sp!, {r0-r12,lr}@ reload saved registers
stmfd sp, {r0-r2} @ save r0-r2
mrs r0, spsr @ get cpsr of interrupt thread
sub r1, sp, #4*3
sub r2, lr, #4 @ save old task's pc to r2
@ switch to SVC mode with no interrupt
msr cpsr_c, #I_Bit|F_Bit|Mode_SVC
stmfd sp!, {r2} @ push old task's pc
stmfd sp!, {r3-r12,lr}@ push old task's lr,r12-r4
ldmfd r1, {r1-r3} @ restore r0-r2 of the interrupt thread
stmfd sp!, {r1-r3} @ push old task's r0-r2
stmfd sp!, {r0} @ push old task's cpsr
ldr r4, =rt_interrupt_from_thread
ldr r5, [r4]
str sp, [r5] @ store sp in preempted tasks's TCB
ldr r6, =rt_interrupt_to_thread
ldr r6, [r6]
ldr sp, [r6] @ get new task's stack pointer
ldmfd sp!, {r4} @ pop new task's cpsr to spsr
msr spsr_cxsf, r4
ldmfd sp!, {r0-r12,lr,pc}^ @ pop new task's r0-r12,lr & pc, copy spsr to cpsr
|
