.section ".text.boot"

.global _start

_start:
	// read cpu id, stop slave cores
	mrs     x1, mpidr_el1
	and     x1, x1, #3
	cbz     x1, 2f
	// cpu id > 0, stop
1:  
	wfe
	b       1b
2:// cpu id == 0
	// set top of stack just before our code (stack grows to a lower address per AAPCS64)
	ldr     x1, =_start
	mov     sp, x1

	// clear bss
	ldr     x1, =__bss_start
	ldr     w2, =__bss_size
3:  
	cbz     w2, 4f
	str     xzr, [x1], #8
	sub     w2, w2, #1
	cbnz    w2, 3b

4:
	// jump to C code, should not return
	bl      main
	// for failsafe, halt this core too
	b       1b