ARM CPSR/SPSR 的示意圖

        ENTRY                           
	EXPORT	__main
__main
SVC_Stack
Mode_SVC	EQU	0x13
I_Bit		EQU	0x80
F_Bit		EQU	0x40

; Set up the SVC stack pointer and return to SVC mode
	MOV		R0, #Mode_SVC:OR:I_Bit:OR:F_Bit ; No interrupts
	MSR		CPSR_c, R0

	LDR		sp, =STACK_ADDR

	nop
	nop
	nop
	nop
	nop
	nop