swihandler.s

ARM汇编实现软中断

       AREA swihandler,CODE,READONLY
       EXPORT   SWIHandler
MAXSWI   EQU   2
SWIHandler
       STMFD	   SP!,{R0-R12,LR}   
       LDR		   R0,[LR,#-4] 
	   BIC         R0,R0,#0XFF000000
	   CMP		   R0,#MAXSWI
	   LDRLE	   PC,[PC,R0,LSL #2]
	   B           OutOfRange
SWIJumpTable
       DCD         SWIEND
       DCD         SWI1
SWI1
       LDMFD       SP!,{R0-R3}
       ADDS        R2,R0,R2           ;R2放结果的低位
       ADC         R3,R1,R3           ;R3放结果的高位
       STMFD       SP!,{R0-R3}
       B           SWIEND
OutOfRange
       NOP
SWIEND
       LDMFD       SP!,{R0-R12,PC}^
       END