This call returns the 8 bytes which define the 8 by 8 matrix of each character.

The call requires a 9 byte parameter block pointed to by the X and Y registers.

The first byte contains the ASCII value of the character definition to be read.

After the call the 8 byte definition is contained in bytes 1 to 8 of the parameter block, with the top row in byte 1 and the bottom row in byte 8.