Alien (BUGFIX 1.7): Routine at 42515

Fills the entire ZX Spectrum attribute file with the value in A. The attribute file occupies 22528-$5AFF (768 bytes). Uses a single LDIR after priming the first byte. Common attribute values: 0=black on black (hidden), 7=white ink on black paper, 32=green ink on black paper.

Input: A = attribute byte to flood-fill

Used by the routines at 38317, 42581, 42821, 43242, 43610 and 44561.

Fills the entire ZX Spectrum attribute file with the value in A. The attribute file occupies 22528-$5AFF (768 bytes). Uses a single LDIR after priming the first byte. Common attribute values: 0=black on black (hidden), 7=white ink on black paper, 32=green ink on black paper. Input: A = attribute byte to flood-fill Used by the routines at 38317, 42581, 42821, 43242, 43610 and 44561.
42515	LD HL,22528	HL = 22528 (start of attribute file)
42518	LD DE,22529	DE = $5801
42521	LD (HL),A	prime first attribute byte
42522	LD BC,767	BC = 767 remaining bytes
42525	LDIR	propagate across entire attribute file
42527	RET