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
|
/*
* FreeRTOS Kernel V10.3.0
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/* Including FreeRTOSConfig.h here will cause build errors if the header file
contains code not understood by the assembler - for example the 'extern' keyword.
To avoid errors place any such code inside a #ifdef __ICCARM__/#endif block so
the code is included in C files but excluded by the preprocessor in assembly
files (__ICCARM__ is defined by the IAR C compiler but not by the IAR assembler. */
#include <FreeRTOSConfig.h>
RSEG CODE:CODE(2)
thumb
EXTERN pxCurrentTCB
EXTERN vTaskSwitchContext
EXTERN vPortSVCHandler_C
PUBLIC xPortPendSVHandler
PUBLIC vPortSVCHandler
PUBLIC vPortStartFirstTask
PUBLIC vPortEnableVFP
PUBLIC vPortRestoreContextOfFirstTask
PUBLIC xIsPrivileged
PUBLIC vResetPrivilege
/*-----------------------------------------------------------*/
xPortPendSVHandler:
mrs r0, psp
isb
/* Get the location of the current TCB. */
ldr r3, =pxCurrentTCB
ldr r2, [r3]
/* Is the task using the FPU context? If so, push high vfp registers. */
tst r14, #0x10
it eq
vstmdbeq r0!, {s16-s31}
/* Save the core registers. */
mrs r1, control
stmdb r0!, {r1, r4-r11, r14}
/* Save the new top of stack into the first member of the TCB. */
str r0, [r2]
stmdb sp!, {r0, r3}
mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY
msr basepri, r0
dsb
isb
bl vTaskSwitchContext
mov r0, #0
msr basepri, r0
ldmia sp!, {r0, r3}
/* The first item in pxCurrentTCB is the task top of stack. */
ldr r1, [r3]
ldr r0, [r1]
/* Move onto the second item in the TCB... */
add r1, r1, #4
dmb /* Complete outstanding transfers before disabling MPU. */
ldr r2, =0xe000ed94 /* MPU_CTRL register. */
ldr r3, [r2] /* Read the value of MPU_CTRL. */
bic r3, r3, #1 /* r3 = r3 & ~1 i.e. Clear the bit 0 in r3. */
str r3, [r2] /* Disable MPU. */
/* Region Base Address register. */
ldr r2, =0xe000ed9c
/* Read 4 sets of MPU registers. */
ldmia r1!, {r4-r11}
/* Write 4 sets of MPU registers. */
stmia r2!, {r4-r11}
ldr r2, =0xe000ed94 /* MPU_CTRL register. */
ldr r3, [r2] /* Read the value of MPU_CTRL. */
orr r3, r3, #1 /* r3 = r3 | 1 i.e. Set the bit 0 in r3. */
str r3, [r2] /* Enable MPU. */
dsb /* Force memory writes before continuing. */
/* Pop the registers that are not automatically saved on exception entry. */
ldmia r0!, {r3-r11, r14}
msr control, r3
/* Is the task using the FPU context? If so, pop the high vfp registers
too. */
tst r14, #0x10
it eq
vldmiaeq r0!, {s16-s31}
msr psp, r0
isb
bx r14
/*-----------------------------------------------------------*/
vPortSVCHandler:
#ifndef USE_PROCESS_STACK /* Code should not be required if a main() is using the process stack. */
tst lr, #4
ite eq
mrseq r0, msp
mrsne r0, psp
#else
mrs r0, psp
#endif
b vPortSVCHandler_C
/*-----------------------------------------------------------*/
vPortStartFirstTask:
/* Use the NVIC offset register to locate the stack. */
ldr r0, =0xE000ED08
ldr r0, [r0]
ldr r0, [r0]
/* Set the msp back to the start of the stack. */
msr msp, r0
/* Clear the bit that indicates the FPU is in use in case the FPU was used
before the scheduler was started - which would otherwise result in the
unnecessary leaving of space in the SVC stack for lazy saving of FPU
registers. */
mov r0, #0
msr control, r0
/* Call SVC to start the first task. */
cpsie i
cpsie f
dsb
isb
svc 0
/*-----------------------------------------------------------*/
vPortRestoreContextOfFirstTask:
/* Use the NVIC offset register to locate the stack. */
ldr r0, =0xE000ED08
ldr r0, [r0]
ldr r0, [r0]
/* Set the msp back to the start of the stack. */
msr msp, r0
/* Restore the context. */
ldr r3, =pxCurrentTCB
ldr r1, [r3]
/* The first item in the TCB is the task top of stack. */
ldr r0, [r1]
/* Move onto the second item in the TCB... */
add r1, r1, #4
dmb /* Complete outstanding transfers before disabling MPU. */
ldr r2, =0xe000ed94 /* MPU_CTRL register. */
ldr r3, [r2] /* Read the value of MPU_CTRL. */
bic r3, r3, #1 /* r3 = r3 & ~1 i.e. Clear the bit 0 in r3. */
str r3, [r2] /* Disable MPU. */
/* Region Base Address register. */
ldr r2, =0xe000ed9c
/* Read 4 sets of MPU registers. */
ldmia r1!, {r4-r11}
/* Write 4 sets of MPU registers. */
stmia r2!, {r4-r11}
ldr r2, =0xe000ed94 /* MPU_CTRL register. */
ldr r3, [r2] /* Read the value of MPU_CTRL. */
orr r3, r3, #1 /* r3 = r3 | 1 i.e. Set the bit 0 in r3. */
str r3, [r2] /* Enable MPU. */
dsb /* Force memory writes before continuing. */
/* Pop the registers that are not automatically saved on exception entry. */
ldmia r0!, {r3-r11, r14}
msr control, r3
/* Restore the task stack pointer. */
msr psp, r0
mov r0, #0
msr basepri, r0
bx r14
/*-----------------------------------------------------------*/
vPortEnableVFP:
/* The FPU enable bits are in the CPACR. */
ldr.w r0, =0xE000ED88
ldr r1, [r0]
/* Enable CP10 and CP11 coprocessors, then save back. */
orr r1, r1, #( 0xf << 20 )
str r1, [r0]
bx r14
/*-----------------------------------------------------------*/
xIsPrivileged:
mrs r0, control /* r0 = CONTROL. */
tst r0, #1 /* Perform r0 & 1 (bitwise AND) and update the conditions flag. */
ite ne
movne r0, #0 /* CONTROL[0]!=0. Return false to indicate that the processor is not privileged. */
moveq r0, #1 /* CONTROL[0]==0. Return true to indicate that the processor is privileged. */
bx lr /* Return. */
/*-----------------------------------------------------------*/
vResetPrivilege:
mrs r0, control /* r0 = CONTROL. */
orr r0, r0, #1 /* r0 = r0 | 1. */
msr control, r0 /* CONTROL = r0. */
bx lr /* Return to the caller. */
/*-----------------------------------------------------------*/
END
|