lowlevel.s.svn-base

RT-Thread是发展中的下一代微内核嵌入式实时操作系统

/*
 * lowlevel.S - low level platform support
 */

#define STACK_END	0xfffc00

#define ENTRY(x)	.global x; .align; x##:

.section ".init", "ax"
.code 32
/* boot loader start point */
ENTRY(_start)
	b	start_vector

start_vector:
	/* set the cpu to SVC32 mode */
	mrs	r0, cpsr
	bic	r0, r0, #0x1f
	orr	r0, r0, #0x13
	msr	cpsr,r0

	/* set SVC32 stack */
	ldr	sp, =_stack_end

	/* mask all IRQs by clearing all bits in the INTMRs */
	ldr	r1, =0x3ff4008
	ldr	r0, =0xffffffff
	str	r0, [r1]

	ldr	pc, _loader_main

_loader_main: 	.word loader_main
_stack_end: 	.word STACK_END

.section ".init", "ax"
.code 32
/* start kernel */
ENTRY(start_kernel)
	bx	r0

.section .tail,"ax"
dummy:
	.byte	0xff