grove/asm/boot.s

// AArch64 mode
.section ".text.boot"
.globl _start 
        .org 0x8000
_start:
	mrc p15, 0, r5, c0, c0, 5
	and r5, r5, #3
	cmp r5, #0
	bne halt
 
	ldr r5, =_start
	mov sp, r5
 
	ldr r4, =__bss_start
	ldr r9, =__bss_end
	mov r5, #0
	mov r6, #0
	mov r7, #0
	mov r8, #0
	b       2f
 
1:	stmia r4!, {r5-r8}
2:	cmp r4, r9
	blo 1b
 
	ldr r3, =kernel_main
	blx r3
 
halt:
	wfe
	b halt