.global kernel_main, __bss, __bss_end, __stack_top

.section .rodata

hello_world: .asciz "\nHello world!\n"

.section .text

bzero:
	la t0, __bss
	la t1, __bss_end

.Lbzero_loop:
	bgt t0, t1, .Lbzero_end
	sw zero, (t0)
	addi t0, t0, 4

.Lbzero_end:
	ret

# Arguments:
# a0 - Character.
.type putchar, @function
putchar:
	li a1, 0
	li a2, 0
	li a3, 0
	li a4, 0
	li a5, 0
	li a6, 0
	li a7, 1 # sbi_console_putchar.

	ecall
	ret

.type kernel_main, @function
kernel_main:
	# Prologue.
	addi sp, sp, -32
	sw ra, 28(sp)
	sw s0, 24(sp)
	addi s0, sp, 32

	sw s1, 20(sp)

	la s1, hello_world

.Lkernel_main_if:
	lw a0, (s1)
	beqz a0, .Lkernel_main

	call putchar
	addi s1, s1, 1

	j .Lkernel_main_if

.Lkernel_main:
	j .Lkernel_main

	lw s1, 20(sp)

	# Epilogue.
	lw ra, 28(sp)
	lw s0, 24(sp)
	add sp, sp, 32
	ret

.section .text.boot
boot:
	la a0, __stack_top
	mv sp, a0 # Set the stack pointer
	call bzero
	j kernel_main