OEL TTX2000 Issue 2.3: Routine at 1243

1243: display_header_row: Decode and display the header row.

Used by the routines at wait_and_decode_page, enter_page, enter_subcode_and_clear, select_channel, hold_page, clear_header and copy_to_header.
display_header_row	1243	PUSH HL	Preserve registers.
	1244	PUSH AF	Preserve registers.
	1245	LD A,(bright_attr)	Add 7 (white ink) to bright_attr and store the result in colour_attr.
	1248	ADD A,$07
	124A	LD (colour_attr),A
	124D	XOR A	Set row_number to 0.
	124E	LD (row_number),A	Set row_number to 0.
	1251	CALL force_decode_row	Decode and display row_number.
	1254	POP AF	Restore registers and return.
	1255	POP HL
	1256	RET