Volex TTX2000 S Issue 1.2: Routine at 0A37

0A37: hold_mosaics_code: Handle hold mosaics code.

Used by the routine at decode_row.
hold_mosaics_code	0A37	LD A,$01	Set hold_mosaics_flag.
	0A39	LD (hold_mosaics_flag),A	Set hold_mosaics_flag.
	0A3C	LD A,(mosaics_flag)	If mosaics_flag is clear then jump to code_set_at.
	0A3F	AND A
	0A40	JP Z,code_set_at
	0A43	LD A,(hold_mosaic_character)	Else copy hold_mosaic_character to character_code and jump to apply_colours.
	0A46	LD (character_code),A
	0A49	JP apply_colours