cvw/tests/testsBP/zsbl/bios.s

PERIOD = 11000000
#PERIOD = 20

.section .init
.global _start
.type _start, @function

		
_start:
	  # Initialize global pointer
	.option push
	.option norelax
	1:auipc gp, %pcrel_hi(__global_pointer$)
	addi  gp, gp, %pcrel_lo(1b)
	.option pop
	
	li x1, 0
	li x2, 0
	li x4, 0
	li x5, 0
	li x6, 0
	li x7, 0
	li x8, 0
	li x9, 0
	li x10, 0
	li x11, 0
	li x12, 0
	li x13, 0
	li x14, 0
	li x15, 0
	li x16, 0
	li x17, 0
	li x18, 0
	li x19, 0
	li x20, 0
	li x21, 0
	li x22, 0
	li x23, 0
	li x24, 0
	li x25, 0
	li x26, 0
	li x27, 0
	li x28, 0
	li x29, 0
	li x30, 0
	li x31, 0


	# set the stack pointer to the top of memory - 8 bytes (pointer size)
	li sp, 0x87FFFFF8

	jal ra, main
	
	fence.i
	# now toggle led so we know the copy completed.

	# write to gpio
	li	t2, 0xFF
	la	t3, 0x1006000C
	li	t4, 5

loop:

	# delay
	li	t0, PERIOD/2
delay1:	
	addi	t0, t0, -1
	bge	t0, x0, delay1
	sw	t2, 0x0(t3)

	li	t0, PERIOD/2
delay2:	
	addi	t0, t0, -1
	bge	t0, x0, delay2
	sw	x0, 0x0(t3)

	addi	t4, t4, -1
	bgt	t4, x0, loop


	# now that the card is copied and the led toggled we
	# jump to the copied contents of the sd card.

jumpToLinux:
	csrr a0, mhartid
        li s0, 0x80000000
        la a1, _dtb
        jr s0
end_of_bios:	



.section .dtb
.globl _dtb
.align 4, 0
_dtb:
.incbin "wally-vcu118.dtb"