/***********************************************************************/
/* This file is part of the CA ARM C Compiler package */
/* Copyright KEIL ELEKTRONIK GmbH 2002 - 2004 */
/***********************************************************************/
/* */
/* SWI_VEC.S: Pre-defined vectored interrupt handler SWI interrupt */
/* */
/***********************************************************************/
AREA ?C?SWI, CODE, READONLY, ALIGN=2
PUBLIC SWI_Handler?A, ?SWI?Table, ?SWI?Empty
SWI_Handler?A PROC CODE32
STMFD SP!,{LR} ; Store LR register
MRS R8,SPSR
TST R8,#0x20 ; SWI call from
LDRNEH R8,[LR,#-2] ; Thumb: Load halfword instruction
ANDNE R8,R8,#0xFF ; extract SWI number
LDREQ R8,[LR,#-4] ; ARM: Load word instruction
BICEQ R8,R8,#0xFF000000 ; extract SWI number
; R4 now contains SWI number
; SWI Handler
; LDR R12,[PC,#(?SWI?Table-$-8)] ; Maximum number of interrupts
; LDR R12,[PC,#0x24] ; Maximum number of interrupts
ADR R12,?SWI?Table
LDR R12,[R12] ; load last SWI-Function-number
CMP R8,R12
BGT ?SWI?Empty ; overflow
ADR R12,?SWI?Table+4
LDR R12,[R12,R8,LSL #2]; SWI function address
MOV LR,PC ; Return address
BX R12 ; Call SWI function
LDMFD SP!,{PC}^ ; Return
?SWI?Empty:
B $ ; no existing SWI
; *** DO NOT MODIFY THIS PORTION OF THE FILE ***
?SWI?Table: ; Marker for LA Linker
;
; The LA Linker inserts at this label
; DD 0 ; <last SWI function number>
; DD ?SWI?Empty ; <entry for SWI function 0>
; DD <SWI entry 1>
; DD <SWI entry 2>
; DD :
; For non-existing SWI functions DD ?SWI?Empty is inserted
ENDP
END
=================================================
下面是官方的例子
int myfunc1 (int x, long y) __swi (8) {
return (x / y);
}
然后在main函数只能够调用
int res；
res = myfunc1 (10, 2); // call SWI functions
这样就可以得出 res = 5
=========================
但是我现在想修改IRQ的状态
请问要怎么做？
|
楼主
标题置顶
标题高亮
