ARM Macro Assembler    Page 1 


    1 00000000 00000080 
                       I_Bit   EQU              0x80
    2 00000000 00000010 
                       USR32Mode
                               EQU              0x10
    3 00000000 00000013 
                       SVC32Mode
                               EQU              0x13
    4 00000000 0000001F 
                       SYS32Mode
                               EQU              0x1f
    5 00000000 00000012 
                       IRQ32Mode
                               EQU              0x12
    6 00000000 00000011 
                       FIQ32Mode
                               EQU              0x11
    7 00000000         
    8 00000000                 CODE32
    9 00000000         
   10 00000000                 AREA             IRQ,CODE,READONLY
   11 00000000         
   12 00000000                 MACRO
   13 00000000         $IRQ_Label
                               HANDLER          $IRQ_Exception_Function
   14 00000000         
   15 00000000                 EXPORT           $IRQ_Label  ; The label for exp
                                                            orts 輸出的標號
   16 00000000                 IMPORT           $IRQ_Exception_Function ; The i
                                                            mported labels 引用
                                                            的外部標號
   17 00000000         
   18 00000000         $IRQ_Label
   19 00000000                 SUB              LR, LR, #4  ; Calculate the ret
                                                            urning address 計算
                                                            返回地址
   20 00000000                 STMFD            SP!, {R0-R3, R12, LR} ; Protect
                                                            s the task environm
                                                            ents 保存任務環境
   21 00000000                 MRS              R3, SPSR    ; Protects the stat
                                                            us variable 保存狀