#define 	PID_OFT		0
#define	STATE_OFT		4
#define	COUNT_OFT		8
#define	PRIORITY_OFT	12
#define	CONTENT_OFT	 	16
#define	KERNELSP_OFT	96
#define	KERNELSTACK_OFT	100

#define	MAX_SWI_NUM		3	
	
@ 虛擬地址=物理地址	
#define	SDRAM_BASE		0x30000000
#define	SDRAM_SIZE		0x04000000		

.extern 	swi_table
.text	
.global HandleSWI
HandleSWI:
	stmdb	sp!,{ r0-r12,lr }	@ 保存使用到的寄存器和返回地址,不必保存那么多，以后要提高實時性時再改吧
	ldr	r4, [lr,#-4]	@ lr-4為指令"swi n"的地址,此指令低24位就是n
	bic	r4, r4,#0xff000000	
	cmp	r4, #3
	ldrls	r5, =swi_table	@ swi跳轉表基址
	ldrls	lr, =swi_return	@ 返回地址
	ldrls	pc, [r5,r4,lsl #2]	@ 跳轉到相應匯編處理函數
	mov	r0, #-1		@ 出錯，返回-1
swi_return:		
	ldmia	sp!,{ r0-r12,pc }^	@ 中斷返回, ^表示將spsr的值復制到cpsr

@ 進程退出處理函數,比如處理main函數退出
.text
.global sys_exit		
sys_exit:
	@ 將調用C函數do_exit(int error_code)
	@ r0=error_code
	ldr	pc, =do_exit	@ do_exit返回到swi_return

.text
.global sys_sleep		
sys_sleep:		
	@ 將調用C函數int sleep(int time)
	@ r0=sleep time
	ldr	pc, =do_sleep	@ do_exit返回到swi_return

.text
.global sys_write		
sys_write:		
	@ 將調用C函數int write(char *str)
	@ r0=sleep time
	ldr	pc, =do_write	@ do_exit返回到swi_return