85: Vectors LDR PC, Reset_Addr ;加载Reset_Addr到寄存器PC中
0x00000000 E59FF018 LDR PC,[PC,#0x0018] ;这里是将PC+0x0018地址处的数据读出保存到PC，一开始PC=0,那么PC+0x0018后就是0x0018,就是说完成这语句后，程序要跳到0x0018该地址了，但是从LDR PC, Reset_Addr 来看，是要跳到Reset_Addr该地址处（0x00000020 00000058 DD 0x00000058）.那这样不是错了吗？
86: LDR PC, Undef_Addr
0x00000004 E59FF018 LDR PC,[PC,#0x0018]
87: LDR PC, SWI_Addr
0x00000008 E59FF018 LDR PC,[PC,#0x0018]
88: LDR PC, PAbt_Addr
0x0000000C E59FF018 LDR PC,[PC,#0x0018]
89: LDR PC, DAbt_Addr
0x00000010 E59FF018 LDR PC,[PC,#0x0018]
90: NOP ; Reserved Vector
91: ; LDR PC, IRQ_Addr
0x00000014 E1A00000 NOP
92: LDR PC, [PC, #-0x0120] ; Vector from VicVectAddr
0x00000018 E51FF120 LDR PC,[PC,#-0x0120]
93: LDR PC, FIQ_Addr
94:
95: Reset_Addr DCD Reset_Handler ;将Reset_Handler加载到当前地址Reset_Addr上
96: Undef_Addr DCD Undef_Handler
97: SWI_Addr DCD SWI_Handler
98: PAbt_Addr DCD PAbt_Handler
99: DAbt_Addr DCD DAbt_Handler
100: DCD 0xB9206E28 ; Reserved Address
101: IRQ_Addr DCD IRQ_Handler
102: FIQ_Addr DCD FIQ_Handler
103:
0x0000001C E59FF018 LDR PC,[PC,#0x0018]
0x00000020 00000058 DD 0x00000058
0x00000024 00000040 DD 0x00000040
0x00000028 00000044 DD 0x00000044
0x0000002C 00000048 DD 0x00000048
0x00000030 0000004C DD 0x0000004C
0x00000034 B9206E28 DD 0xB9206E28
0x00000038 00000050 DD 0x00000050
0x0000003C 00000054 DD 0x00000054
104: Undef_Handler B Undef_Handler
0x00000040 EAFFFFFE B 0x00000040
105: SWI_Handler B SWI_Handler
0x00000044 EAFFFFFE B 0x00000044
106: PAbt_Handler B PAbt_Handler
0x00000048 EAFFFFFE B 0x00000048
107: DAbt_Handler B DAbt_Handler
0x0000004C EAFFFFFE B 0x0000004C
108: IRQ_Handler B IRQ_Handler
0x00000050 EAFFFFFE B 0x00000050
109: FIQ_Handler B FIQ_Handler
110:
111: ; Reset Handler
112:
113: EXPORT Reset_Handler
114: Reset_Handler
115:
116: ; Setup Stack for each mode
0x00000054 EAFFFFFE B 0x00000054
117: LDR R0, =Stack_Top
118:
119: ; Enter Undefined Instruction Mode and set its Stack Pointer
0x00000058 E59F0050 LDR R0,[PC,#0x0050]
120: MSR CPSR_c, #Mode_UND:OR:I_Bit:OR:F_Bit ; :OR: Mode_UND,I_Bit,F_Bit之间按位作逻辑或操作，设置未定义模式，禁止FIQ,IRQ
0x0000005C E321F0DB MSR CPSR_c,#0x000000DB
121: MOV SP, R0 ;堆指针指向栈顶
0x00000060 E1A0D000 MOV R13,R0
122: SUB R0, R0, #UND_Stack_Size ;把减去"未定义模式的栈"大小后的地址存放在R0(那么从开始的栈顶到该地址之间的大小为未定义模式分配的栈的大小)，R0只是一个存放东西的容器，它会随着存放内容同而更新自己的值
123:
124: ; Enter Abort Mode and set its Stack Pointer
0x00000064 E2400000 SUB R0,R0,#0x00000000
125: MSR CPSR_c, #Mode_ABT:OR:I_Bit:OR:F_Bit
0x00000068 E321F0D7 MSR CPSR_c,#0x000000D7
126: MOV SP, R0 ;ABT模式的栈指针指向R0中存放的地址
0x0000006C E1A0D000 MOV R13,R0
127: SUB R0, R0, #ABT_Stack_Size ;分配ABT模式的栈大小,
128:
129: ; Enter FIQ Mode and set its Stack Pointer
0x00000070 E2400000 SUB R0,R0,#0x00000000
130: MSR CPSR_c, #Mode_FIQ:OR:I_Bit:OR:F_Bit
0x00000074 E321F0D1 MSR CPSR_c,#0x000000D1
131: MOV SP, R0
0x00000078 E1A0D000 MOV R13,R0
132: SUB R0, R0, #FIQ_Stack_Size
133:
134: ; Enter IRQ Mode and set its Stack Pointer
0x0000007C E2400000 SUB R0,R0,#0x00000000
135: MSR CPSR_c, #Mode_IRQ:OR:I_Bit:OR:F_Bit
0x00000080 E321F0D2 MSR CPSR_c,#0x000000D2
136: MOV SP, R0
0x00000084 E1A0D000 MOV R13,R0
137: SUB R0, R0, #IRQ_Stack_Size
138:
139: ; Enter Supervisor Mode and set its Stack Pointer
0x00000088 E2400C01 SUB R0,R0,#0x00000100
140: MSR CPSR_c, #Mode_SVC:OR:I_Bit:OR:F_Bit
0x0000008C E321F0D3 MSR CPSR_c,#0x000000D3
141: MOV SP, R0
0x00000090 E1A0D000 MOV R13,R0
142: SUB R0, R0, #SVC_Stack_Size ;分配管理模式堆栈的大小，R0现在存储着该堆栈的最底下地址（栈底）
143:
144: ; Enter User Mode and set its Stack Pointer
0x00000094 E2400C01 SUB R0,R0,#0x00000100
145: MSR CPSR_c, #Mode_USR
0x00000098 E321F010 MSR CPSR_c,#0x00000010
146: MOV SP, R0
0x0000009C E1A0D000 MOV R13,R0
147: SUB SL, SP, #USR_Stack_Size ;到这里，所有模式的堆栈已经分配好，SL存储着用户模式堆栈的最底下地址（栈底）
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