; z80dasm 1.1.6
; command line: z80dasm -a -l -g 0x00 -t -v -o 2708-Patrick-PKTB.dasm TMS2708@DIP24_Patrick-PKTB.BIN
; firmware for the keyboard & printer board

P006h:	equ	I/O port 06h, used for input and output
P007h:	equ	I/O port 07h, used for output

INTCODE:	equ	4000h
NMICODE:	equ	4006h

	org	00000h

l0000h:
	im 1		;0000	ed 56 	. V 
	ld hl,l009dh		;0002	21 9d 00 	! . .  copy
	ld de,04000h		;0005	11 00 40 	. . @  last three 
	ld bc,00003h		;0008	01 03 00 	. . .  bytes to
	ldir			;000b	ed b0 	. .            4000h (RAM?)
	jp 00070h		;000d	c3 70 00 	. p . 
	
l0010h:	;; Is the next block used? Not from this EPROM
	dec c			;0010	0d 	. 
	nop			;0011	00 	. 
	sbc hl,de		;0012	ed 52 	. R 
	ld (00d75h),hl		;0014	22 75 0d 	" u . 
	ld bc,l0269h		;0017	01 69 02 	. i .  zero memory
	ld hl,00db0h		;001a	21 b0 0d 	! . .  range from
	ld (hl),000h		;001d	36 00 	6 .            0db1h - 0db1h + 0269h
	ld de,00db1h		;001f	11 b1 0d 	. . . 
	ldir		;0022	ed b0 	. . 
	ld hl,l0000h		;0024	21 00 00 	! . . 
	ld (00d69h),hl		;0027	22 69 0d 	" i . 
	ld (00d6bh),hl		;002a	22 6b 0d 	" k . 
	ld (00d61h),hl		;002d	22 61 0d 	" a . 
	ld (00d63h),hl		;0030	22 63 0d 	" c . 
	ld (ix-00bh),000h		;0033	dd 36 f5 00 	. 6 . . 
	defb	3ah

l0038h:							; target if Mode 1 interrupt
	jp 04000h		;0038	c3 00 40 	. . @ 

l003bh: ; target of the jump in RAM @4000h
	in a,(006h)		;003b	db 06 	. .  read byte from CPU
	ld d,a			;003d	57 	W    keep it
	xor a			;003e	af 	.    and write 00h
	out (006h),a		;003f	d3 06 	. .  back (status?)
	ret			;0041	c9 	. ? where is the call? Or is it a legitimate alternate for reti?
	
	ld l,a			;0042	6f 	o 
	dec c			;0043	0d 	. 
	add hl,de			;0044	19 	. 
	ld (hl),00dh		;0045	36 0d 	6 . 
	xor a			;0047	af 	. 
	ld (00d86h),a		;0048	32 86 0d 	2 . . 
	ex de,hl			;004b	eb 	. 
l004ch:
	dec de			;004c	1b 	. 
	ld hl,(00d6fh)		;004d	2a 6f 0d 	* o . 
	or a			;0050	b7 	. 
	sbc hl,de		;0051	ed 52 	. R 
	jr nc,l00a6h		;0053	30 51 	0 Q 
	ld a,(de)			;0055	1a 	. 
	cp 02fh			;0056	fe 2f 	. / 
	jr nz,l004ch		;0058	20 f2 	  . 
	ld a,00dh		;005a	3e 0d 	> . 
	ld (de),a			;005c	12 	. 
	inc de			;005d	13 	. 
	ld a,001h		;005e	3e 01 	> . 
	ld (00d86h),a		;0060	32 86 0d 	2 . . 
	ld a,(de)			;0063	1a 	. 
	inc de			;0064	13 	. 
	defb	0feh		;0065
l0066h:	
	jp 04006h		;0066	c3 06 40 	. . @ 

	cp 043h			;0069	fe 43 	. C 
	jr nz,l0071h		;006b	20 04 	  . 
	defb 0ddh,0cbh,0f5h	;006d	dd cb f5  	. . . ! garbage?
l0070h:
l0071h: ;; this lands halfway the next instruction. Is the whole block from l004ch garbage?
	ld de,00		;0070	21 00
	add a,b			;0072	80 	. 
	ld sp,hl			;0073	f9 	. 
	xor a			;0074	af 	. 
	out (007h),a		;0075	d3 07 	. . output 00h
	ld a,080h		;0077	3e 80 	> . 
	out (006h),a		;0079	d3 06 	. . output 80h
	ld hl,04003h		;007b	21 03 40 	! . @ used in next interrupt ?
	ei			;007e	fb 	. 
	halt			;007f	76 	v 
	
	ld c,d			;0080	4a 	J 
	ei			;0081	fb 	. 
	halt			;0082	76 	v 
	
	ld b,d			;0083	42 	B 
l0084h:
	ei			;0084	fb 	. 
	halt			;0085	76 	v 
	
l0086h:
	ld (hl),d			;0086	72 	r 
	inc hl			;0087	23 	# 
	dec bc			;0088	0b 	. 
	xor a			;0089	af 	. 
	cp c			;008a	b9 	. 
	jp nz,l0084h		;008b	c2 84 00 	. . . 
	cp b			;008e	b8 	. 
	jp nz,l0084h		;008f	c2 84 00 	. . . 
	ld hl,04000h		;0092	21 00 40 	! . @ 
	xor a			;0095	af 	. 
	ld (hl),a			;0096	77 	w 
	inc hl			;0097	23 	# 
	ld (hl),a			;0098	77 	w 
	di			;0099	f3 	. 
	jp 04009h		;009a	c3 09 40 	. . @ 
	
l009dh:	; moved to 4000h and used in Interrupt 1 code
	jp l003bh		;009d	c3 3b 00 	. ; . 
	rst 38h