start:	ld 100,x1
	ld end,xC
	jmp sqrt
end:	out x8,!0xe
	out x0,!0xe
	hlt

; Binary search for square root of x1. Will only take 16 iterations at most.
; x1 is unsigned. Rounds down to integer. Return value in x8.
sqrt:	ld 0x8000,xA ; Bit to test.
	ld -1,x9     ; For shifting xA.
	xor x0,x0,x8 ; Accumulator.
	; Test this bit.
sqrtl:	or xA,x8,x8
	mul x8,x8,xB
	xor xB,x1,x0
	jnf xC       ; Exact result found; x1 is a square number.
	sub xB,x1,x0
	jnf keepbit
	xor xA,x8,x8
keepbit:
	shf xA,x9,xA
	xor xA,x0,x0
	jf sqrtl
	jmp xC