draw1:	6M for draw 0,0,100,100 no repl
draw3:	4M for draw 0,0,100,100 no repl
just read src, dst - 250k
mask reading - 650k
write dst - 100k
alpha calculation - 3000k

olddraw:	10M for draw 0, 0, 1000, 1000 no repl all ldepth 3
		44M for draw 0, 0, 1000, 1000 src, mask ldepth 2 dst ldepth 3
draw4:	160M for draw 0, 0, 1000, 1000 no repl all r8g8b8
	null loop: 10k
	src, dst reading: 13-15M each
	mask reading: 30M
	alpha calculation loop: 90M
		null alpha loop: 2M
		minimal loop control +20M
		alpha calculation with divides +190M
		alpha calculation wtih shifts +70M
	writeback: 11M