# Conv24ToGrey(dst:r3:PTR TO chunky,src:r4:PTR TO chunky32)


	.text
	.global	_Conv24ToGrey

_Conv24ToGrey:
	mfctr	r9

	lwz	r5,4(r3)
	lwz	r0,0(r3)
	mullw	r5,r5,r0
	lwz	r3,8(r3)		# get dst data address
	lwz	r4,8(r4)		# get src data address
	subi	r3,r3,1
	subi	r4,r4,4

	mtctr	r5
	li	r0,3
.loop:	lwzu	r6,4(r4)
	srwi	r7,r6,8
	srwi	r8,r6,16
	andi.	r6,r6,0xff
	andi.	r7,r7,0xff
	andi.	r8,r8,0xff
	add	r6,r6,r7
	add	r6,r6,r8
	divw	r6,r6,r0
	stbu	r6,1(r3)

	bdnz	.loop

	mtctr	r9
	blr