This Function takes a byte in, and returns the byte that has reflected the bits around the x axis, such that bits 7,6,5,4,3,2,1,0 become bits 0,1,2,3,4,5,6,7.
This can be useful if you elect to make all your graphics face in one direction - you can mirror the bytes (perhaps to a buffer or a UDG) before you print them. It's faster to store them facing both ways, but you can make quite a memory saving if you just choose one way.
FUNCTION FASTCALL hMirror (number AS UBYTE) AS UBYTE ASM ld c,a ; unrolled LOOP FOR speed. Still quite small - costs 10 bytes OVER the LOOP version, AND saves OVER half the time. RR C RLA RR C RLA RR C RLA RR C RLA RR C RLA RR C RLA RR C RLA RR C RLA END ASM END FUNCTION