RISC-V Loop Termination

So I'm trying things out with assembly and I have a problem that involves counting set bits in a register. I have the code below but I can't seem to figure out how I'll stop this loop cause it goes on and on shifting the bits and ends up with an invalid c开发者_开发百科ount.

addi x9, x0, 0xff00
addi x10, x0, 1 # adding counter for AND function
addi x11, x0, 0 # bit counter count
addi x12, x0, 0 # to compare 0

and x13, x9, x10
#bge x10, x9, func_c             # this somehow works with positive numbers only
bne x13, x12,func_a  # go to func_a if not equal to 0
beq x13, x12, func_b # else go to funcb_b

func_a:
addi x11, x11, 1     # add one to bit count
slli x10, x10, 1     # shift left
and x13, x9, x10     # new x13
bne x13, x12, func_a # not equal to 0
beq x13, x12, func_b

func_b:
slli x10, x10, 1 # shift left
and x13, x9, x10
#jal x0, -40 # go to line 7      # this jumped to the commented `bge` instruction above
jal x0, -36 # go to line 8

func_c:
add x20, x0, x11 # store final count