CPC split screen. Example demonstrates displaying the top 4 character rows starting from 0xc000, and the rest 0x8000

split-ex1.asm

	org &4000
	run &4000
	jp start

vsync
	ld b, &f5
	in a, (c)
	rra
	jr nc, vsync
	in a, (c)
	rra
	jr c, vsync
	ret

start
	di
	ld	a, &fb
	ld	(&38), a
	ld	a, &c9
	ld	(&39), a
	ei

	ld	hl, &8000
	ld	(hl), &0f
	ld	de, &8001
	ld	bc, &3fff
	ldir

frame
	call	vsync

	halt

ds 64*8*4

	ld bc, &bc00+4
	out (c), c
	ld bc, &bd00+4-1
	out (c), c

	ld bc, &bc00+12
	out (c), c
	ld bc, &bd00+&20
	out (c), c

	halt

	ld bc, &bc00+4
	out (c), c
	ld bc, &bd00+39-1-4
	out (c), c

	ld bc, &bc00+7
	out (c), c
	ld bc, &bd00+31-1-4
	out (c), c

	ld bc, &bc00+6
	out (c), c
	ld bc, &bd00+25-1-4
	out (c), c

	ld bc, &bc00+12
	out (c), c
	ld bc, &bd00+&30
	out (c), c

	jp	frame