source: trunk/firmware/STM32G0xx_Startup.s@ 12

Last change on this file since 12 was 6, checked in by f.jahn, 8 months ago
File size: 6.5 KB
Line 
1/*********************************************************************
2* SEGGER Microcontroller GmbH *
3* The Embedded Experts *
4**********************************************************************
5* *
6* (c) 2014 - 2019 SEGGER Microcontroller GmbH *
7* *
8* www.segger.com Support: support@segger.com *
9* *
10**********************************************************************
11* *
12* All rights reserved. *
13* *
14* Redistribution and use in source and binary forms, with or *
15* without modification, are permitted provided that the following *
16* conditions are met: *
17* *
18* - Redistributions of source code must retain the above copyright *
19* notice, this list of conditions and the following disclaimer. *
20* *
21* - Neither the name of SEGGER Microcontroller GmbH *
22* nor the names of its contributors may be used to endorse or *
23* promote products derived from this software without specific *
24* prior written permission. *
25* *
26* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND *
27* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, *
28* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF *
29* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE *
30* DISCLAIMED. *
31* IN NO EVENT SHALL SEGGER Microcontroller GmbH BE LIABLE FOR *
32* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR *
33* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT *
34* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; *
35* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF *
36* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT *
37* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE *
38* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH *
39* DAMAGE. *
40* *
41*********************************************************************/
42
43/*****************************************************************************
44 * Preprocessor Definitions *
45 * ------------------------ *
46 * NO_STACK_INIT *
47 * *
48 * If defined, the stack pointer will not be initialised. *
49 * *
50 * NO_SYSTEM_INIT *
51 * *
52 * If defined, the SystemInit() function will not be called. By default *
53 * SystemInit() is called after reset to enable the clocks and memories to *
54 * be initialised prior to any C startup initialisation. *
55 * *
56 * NO_VTOR_CONFIG *
57 * *
58 * If defined, the vector table offset register will not be configured. *
59 * *
60 * MEMORY_INIT *
61 * *
62 * If defined, the MemoryInit() function will be called. By default *
63 * MemoryInit() is called after SystemInit() to enable an external memory *
64 * controller. *
65 * *
66 * STACK_INIT_VAL *
67 * *
68 * If defined, specifies the initial stack pointer value. If undefined, *
69 * the stack pointer will be initialised to point to the end of the *
70 * RAM segment. *
71 * *
72 * VECTORS_IN_RAM *
73 * *
74 * If defined, the exception vectors will be copied from Flash to RAM. *
75 * *
76 *****************************************************************************/
77
78 .syntax unified
79
80 .global Reset_Handler
81 .extern _vectors
82
83 .section .init, "ax"
84 .thumb_func
85
86 .equ VTOR_REG, 0xE000ED08
87
88#ifndef STACK_INIT_VAL
89#define STACK_INIT_VAL __RAM_segment_end__
90#endif
91
92Reset_Handler:
93#ifndef NO_STACK_INIT
94 /* Initialize main stack */
95 ldr r0, =STACK_INIT_VAL
96 ldr r1, =0x7
97 bics r0, r1
98 mov sp, r0
99#endif
100
101#ifndef NO_SYSTEM_INIT
102 /* Initialize system */
103 ldr r0, =SystemInit
104 blx r0
105 .pushsection .init_array, "aw", %init_array
106 .align 2
107 .word SystemCoreClockUpdate
108 .popsection
109#endif
110
111#ifdef MEMORY_INIT
112 ldr r0, =MemoryInit
113 blx r0
114#endif
115
116#ifdef VECTORS_IN_RAM
117 /* Copy exception vectors into RAM */
118 ldr r0, =__vectors_start__
119 ldr r1, =__vectors_end__
120 ldr r2, =__vectors_ram_start__
1211:
122 cmp r0, r1
123 beq 2f
124 ldr r3, [r0]
125 str r3, [r2]
126 adds r0, r0, #4
127 adds r2, r2, #4
128 b 1b
1292:
130#endif
131
132#ifndef NO_VTOR_CONFIG
133 /* Configure vector table offset register */
134 ldr r0, =VTOR_REG
135#ifdef VECTORS_IN_RAM
136 ldr r1, =_vectors_ram
137#else
138 ldr r1, =_vectors
139#endif
140 str r1, [r0]
141#endif
142
143 /* Jump to program start */
144 b _start
145
146
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