_bigint_square:
; Destination needs space for 61 bytes during computation (But at the end, only the first 30 bytes contain valid data)
; Input: DE: Start of source, IY: Start of destination
; Output: A destroyed, B=C=0, DE: Start of destination + 10, HL: Start of destination + 9, IY: Start of destination + 31
	ld hl, -61
	call ti._frameset
	lea iy, ix - 61			; using a temp buffer for dest
	ld hl, (ix + 9)			; iy = src
	ld c,30
.byteLoop:
	ld a, (de)
	inc de
	ld b, 8
	.bitLoop:
		add hl, hl
		rla
		adc hl, hl
		djnz .bitLoop
	ld (iy), hl
	lea iy, iy + 2
	dec c
	jr nz, .byteLoop

	ld b, 29
	.reduceLoop:
		dec iy
		ld hl, (iy - 2)
		ld a, h
		rra
		ld a, l
		rra
		xor a, (iy - 31)
		ld (iy - 31), a
		add hl, hl
		lea de, iy - 21
		ld a, (de)
		xor a, h
		ld (de), a
		djnz .reduceLoop

	ld a, l
	rrca
	and a, 1
	ld (iy - 2), a
	rlca
	xor a, l
	lea hl, iy - 22
	xor a, (hl)
	ld (hl), a

	; copy tmp buffer to dest
	ld de, (ix + 6)
	lea hl, ix - 61
	ld bc, 30
	ldir

	ld sp, ix
	pop ix
	ret