Fix aoff &= ~BMPC_BUFSZ and a little optimize
Fix aoff &= ~BMPC_BUFSZ and a little optimize

pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable