@ boot.S (ARM, Cortex-A9 / ARMv7-A) — minimal entry for the Zynq PS.
@ QEMU 'xilinx-zynq-a9' enters at the image load address. We set a stack,
@ clear .bss, and call kmain(). Irreducible asm part for ARM.

	.section .text.boot
	.global _start
_start:
	@ Park secondary CPUs: only CPU0 continues.
	mrc	p15, 0, r1, c0, c0, 5   @ read MPIDR
	and	r1, r1, #3              @ CPU id (affinity level 0)
	cmp	r1, #0
	bne	park

	ldr	sp, =_stack_top         @ set up the stack

	@ Zero .bss: [__bss_start, __bss_end)
	ldr	r0, =__bss_start
	ldr	r1, =__bss_end
	mov	r2, #0
1:	cmp	r0, r1
	bge	2f
	str	r2, [r0], #4
	b	1b
2:
	bl	kmain

park:
	wfi
	b	park