Optimizations

[dac514]

Have you seen this fork?

https://github.com/sj-i/php-terminal-nes-emulator/tree/optimize

I've gone from 5fps to 10fps just like that.

[hasegawa-tomoki]

Thanks for your information.
Yes, I know that and I tried.
But I can't see fps gain with super Mario bros.
So, now, I want to keep code readability.