* entry point
a000	b	@fdc0


* Called when "CO" is compiling the first variable?
* The code at @fdfc comes from the mystery sector
e2b0	blwp	@fdfc


* Read sector >13 from track >21
* transfer it to fdc0
* transfer 32 bytes from VDP@1100 to fec0
fdc0	lwpi	ff18
	li	r0,@837e
	clr	@fffc
	clr	@fffe
	li	r0,b7b2		Change entry point to b7b2 (??)
	mov	r0,@a002
	b	@fe34


* Send command to disk controller
fde4	mov	*r11+,r9
	x	r15		1000 (NOP?)
	movb	@5ff0,r10
	sla	r10,1
	sbz	1
	sbo	1
	jnc	fe00
...
fe00	movb	r9,@5ff8
	sbo	3
6 X	swpb	r5
	rt


* wait for disk controller command completion
fe14	movb	@5ff0,r9
	x	r15
	movb	r9,r0
	jlt	fe24
	src	r0,9
	joc	fe14
	rt


* setup disk controller, etc.
fe34	lwpi	ff18
	li	r12,1100
	sbo	0
	bl	@fed4		????
	mov	@ff14,r15
	ai	r15,fde0
	mov	*r15,r15
	mov	@ff14,@ff14
	jne	fe5a
fe54..fe60	sbo b,a,8,4,5,6,7
	li	r0,c80
fe66	swpb	r0
	swpb	r0
	dec	r0
	jne	fe66
	movb	@5ff2,r9	track reg
	movb	r9,@5ffa	track reg
	li	r9,2113
	x	r15		1000 (NOP?)
	movb	r9,@5ffe	data reg = 21 (track #)
	swpb	r9
	movb	r9,@5ffc	sector reg = 13
	bl	fde4		send command
	data	1e00		seek command
	bl	fe14		wait for completion
	sla	r0,13
	joc	fe24
	li	r2,8c00
	li	r0,fff
	clr	r1
	blwp	@ab4c		VSBW?
	mov	@ff14,@ff14
	jeq	feb2		read sector

* transfer the mystery sector to VDP@1000
feb2	bl	@fde4		send command
	data	8600		read sector command
	li	r6,100
	sbo	2
febe	movb	@5ff6,r9
	x	r15
	movb	r9,*r2
	dec	r6
	jne	febe
feca	sbz	2
	bl	@fe14		wait for completion
	b	@fef4


* ????
fed4	li	r0,4300
	li	r1,5000
	clr	r2
fede	a	*r0+,r2
	c	r0,r1
	jl	fede
fee4	c	r2,@ff16
	jne	fef2
...
fef2	rt


* transfer 288 bytes from vdp@1000 to @fdc0
* and jump to b29e
fef4	li	r0,1000
	li	r1,fdc0
	li	r2,120
	blwp	@ab36
	mov	@ff14,@ff14
	jne	ff0e
	sbz	b
	sbz	0
	b	@b29e		main entry point?