path: root/z180/r3init.180

	page	255
	.z80

	extrn ddtz,bpent
	extrn $stack
	extrn charini,?const,?conin

	extrn romend


	global	isv_sw

	include config.inc
	include	z180reg.inc
	include z180.lib

;CR	equ	0dh



;----------------------------------------------------------------------

	cseg

	jp start

; restart vectors

rsti	defl	1
	rept	7
	 db 0, 0, 0, 0, 0
	 jp bpent
rsti	 defl rsti+1
	endm
	 db 0, 0, 0, 0, 0

;----------------------------------------------------------------------
	
	;org	40h

	dw	0
	db	0


	if ROMSYS
$crom:	 defb c$rom		;
	else
	 db	0		;
	endif

dmclrt:				;clear ram per dma
	db	dmct_e-dmclrt-2 ;
	db	sar0l		;first port
	dw	nullbyte	;src (fixed)
nullbyte:
	db 	000h		;src
	dw	romend		;dst (inc), start after "rom" code
	db	00h		;dst
	dw 	0-romend	;count (64k)
dmct_e:

INIWAITS defl	CWAITIO
	if	ROMSYS
INIWAITS defl	INIWAITS+CWAITROM
	endif

hwini0:
	db	3		;count
	db	rcr,CREFSH	;configure DRAM refresh
	db	dcntl,INIWAITS	;wait states
	db	cbar,SYS$CBAR

;----------------------------------------------------------------------

start:
	ld	(tmpstack),sp
	ld	sp,tmpstack
	push af
	in0 a,(itc)		;Illegal opcode trap?
	jp m,??st01
	ld a,i			;I register == 0 ?
	jr z,??st02		;    yes, harware reset

??st01:
	ld	a,(syscbr)
	out0	(cbr),a
	pop af			;restore registers
	ld	sp,(tmpstack)	;
	jp bpent		;

??st02:
	di			;0058
	ld	a,CREFSH
	out0	(rcr),a		;	configure DRAM refresh
	ld	a,CWAITIO
	out0	(dcntl),a	;	wait states

	ld	a,M_NCD		;No Clock Divide
	out0	(ccr),a
;	ld	a,M_X2CM	;X2 Clock Multiplier
;	out0	(cmr),a

; search warm start mark

	ld ix,mark_55AA		;00b8	; top of common area
	ld a,SYS$CBAR		;
	out0 (cbar),a		;
	ld a,071h		;00bc
	ex af,af'		;00be	;for cbr = 0x70 downto 0x40
swsm_l:
	ex af,af'		;00bf
	dec a			;00c0
	cp 03fh			;00c1
	jr z,kstart		;00c3	;  break (mark not found)
	out0 (cbr),a		;00c5
	ex af,af'		;00c8
	ld a,0aah		;00c9
	cp (ix+000h)		;00cb
	jr nz,swsm_l		;00ce
	cp (ix+002h)		;00d0
	jr nz,swsm_l		;00d3
	cpl			;00d5
	cp (ix+001h)		;00d6
	jr nz,swsm_l		;00d9
	cp (ix+003h)		;00db
	jr nz,swsm_l		;00de
	ld sp,$stack		;00e0	mark found, check
	call checkcrc_alv	;00e3
	jp z,wstart		;00e6	check ok,

;
; ram not ok, initialize    --  kstart --

kstart:

	ld	a,088h		;00e9	0000-7fff: common 0
	out0	(cbar),a	;00eb   8000-ffff: common 1
	ld	ix,08000h	;00f3
	ld	a,0		;00f1	start at 008000 (2. phys. 32k block)
??f_0:
	out0	(cbr),a		;00f9

	ld	(ix+0),a	;0103
	cpl
	ld	(ix+1),a	;0103
	cpl
	add	a,8		;010a	next 'bank'
	cp	078h		;010c	stop at 078000
	jr	nz,??f_0	;010e

	ld	de,8000h	;0114   first block not tested, but mark as ok
	ld	a,0		;00f1	start at 008000 (2. phys. 32k block)
??cp_0:
	out0	(cbr),a		;011c
	ld	c,a
	xor	(ix+0)
	ld	b,a
	ld	a,c
	cpl
	xor	(ix+1)
	or	b
	jr	nz,??cp_1
	scf
??cp_1:
	rr	d
	rr	e
	ld	a,c
	add	a,8
	cp	078h		;	stop at 078000
	jr	nz,??cp_0

;
;  ram test found 1 or more error free blocks (32k)
;

ramok:
	ld	a,SYS$CBAR	;01c8
	out0	(cbar),a	;01ca
	ld	h,d
	ld	l,e
	ld 	c,070h		;01ce	highest block
	ld 	b,15		;01d0
??sr_1:
	add	hl,hl
	jr	c,alloc		;01d4	highest "error free" block
	ld	a,c		;01d6
	sub	008h		;01d7
	ld	c,a		;01d9
	djnz	??sr_1		;01da

	slp			;01dc	should never be reached

alloc:
	out0	(cbr),c		;01de
	ld	a,c
	ld	(syscbr),a
	ld	sp,$stack	;01e1

; Clear RAM using DMA0

	ld	hl,dmclrt	;load DMA registers
	call	io.ini.m
	ld	a,0cbh		;01ef	dst +1, src fixed, burst
	out0	(dmode),a	;01f1

	ld	b,512/64
	ld	a,062h		;01f4	enable dma0,
??cl_1:
	out0	(dstat),a	;01f9	clear (up to) 64k
	djnz	??cl_1		;	end of RAM?

; Init bank manager

	ld	hl,banktabsys	;020f
	ld	(hl),c		;	Common area
	inc	hl		;0213
	ld	(hl),c		;	System work area
	inc	hl		;0215	Point to bank 0 entry
	ld	b,BANKS		;0216
l0218h:
	ld	(hl),0ffh	;0218	Mark all banks as unassigned
	inc	hl		;021a
	djnz	l0218h		;021b

	ld	hl,memalv	;
	ld	b,8		;	8*4k ie. first 32k
??a_0:
	ld	(hl),0e0h	;	mark as sys ("rom"/monitor)
	inc	hl
	djnz	??a_0

	rr	d		;	shift out bit for block 0
	rr	e		;
	ld	c,15		;022c	15*32k remaining blocks
l022eh:
	ld	a,0feh		;	0xfe == block with error(s)
	rr	d		;
	rr	e
	adc	a,0		;	==> 0xff : block ok
	ld	b,32/4		;	32k == 8 * 4k
l0236h:
	ld	(hl),a		;
	inc	hl		;
	djnz	l0236h		;
	dec	c		;
	jr	nz,l022eh	;next 32k block

	ld	hl,memalv+0ch	;memalv+0ch
	ld	a,(banktabsys)	;
	call	add_hl_a
	ld	b,3		;
l024ah:
	ld	(hl),0ech	;alloc system ram
	inc	hl		;
	djnz	l024ah		;
	ld	(hl),0efh	;alloc common
	call	gencrc_alv

	ld	hl,0000h	;bank #
	ld	bc,0f0fh	;  size (?) (4k blocks)
	xor	a		;
	call	sub_0420h	;alloc mem for bank 0
	ld	c,l		;
	or	a		;
	call	z,sub_04b5h	;

	ld	hl,0101h	;
	ld	bc,0f0fh	;
	xor	a		;
	call	sub_0420h	;
	ld	c,l		;
	or	a		;
	call	z,sub_04b5h	;

	ld	hl,055AAh	;set warm start mark
	ld	(mark_55AA),hl	;
	ld	(mark_55AA+2),hl;

;
; crc ok       --  wstart  --
;
wstart:
	call	sysram_init	;027f
	call	ivtab_init

	call	prt0_init

	call	charini

	call	bufferinit



	im 2			;?030e
	ei			;0282

	call ?const		;0284
	call ?const		;0287
	or a			;028a
	call nz,?conin		;028d

	ld a,(banktab)		;
	ld e,a			;
	jp ddtz			;0290


	ds	8
tmpstack:
	dw	2
syscbr:	db	1

;
;----------------------------------------------------------------------
;

;TODO: Make a ringbuffer module.

	global	buf.init

buf.init:
	ld	(ix+o.in_idx),0
	ld	(ix+o.out_idx),0
	ld	(ix+o.mask),a
	ret

;----------------------------------------------------------------------
if 0
	extrn	msginit,msg_tx_fifo,msg_rx_fifo
	extrn	msg.sout

bufferinit:

	ld	de,msg_tx_fifo
	in0	a,cbr
	call	log2phys
	ld	(40h+0),hl
	ld	(40h+2),a

;	ld	(bufdat+1),hl
;	ld	(bufdat+3),a
;	ld	a,1
;	ld	(bufdat+0),a
;	ld	hl,inimsg
;	call	msg.sout

	ld	de,msg_rx_fifo
	in0	a,cbr
	call	log2phys
	ld	(bufdat+1),hl
	ld	(bufdat+3),a
	ld	a,2
	ld	(bufdat+0),a
	ld	hl,inimsg
	call	msg.sout

	ret

inimsg:
	db	inimsg_e - $ - 1
	db	0AEh
	db	inimsg_e - $ - 1
	db	0
bufdat:
	db	0
	dw	0
	db	0
inimsg_e:

endif
;----------------------------------------------------------------------
;

	extrn	msginit,msg.sout
	extrn	mtx.fifo,mrx.fifo
	extrn	co.fifo,ci.fifo


bufferinit:
	call	 msginit

	ld	hl,buffers
	ld	b,buftablen
bfi_1:
	ld	a,(hl)
	inc	hl
	ld	(bufdat+0),a
	ld	e,(hl)
	inc	hl
	ld	d,(hl)
	inc	hl
	push	hl

	or	a
	jr	nz,bfi_2
	in0	a,cbr
	call	log2phys
	ld	(40h+0),hl
	ld	(40h+2),a
	out0	(AVRINT5),a
	jr	bfi_3	
bfi_2:
	in0	a,cbr
	call	log2phys
	ld	(bufdat+1),hl
	ld	(bufdat+3),a
	ld	hl,inimsg
	call	msg.sout
bfi_3:
	pop	hl
	djnz	bfi_1
	ret

buffers:
	db	0
	dw	mtx.fifo
	db	1
	dw	mrx.fifo
	db	2
	dw	co.fifo
	db	3
	dw	ci.fifo
buftablen equ	($ - buffers)/3

inimsg:
	db	inimsg_e - $ -1
	db	0AEh
	db	inimsg_e - $ -1
	db	0
bufdat:
	db	0
	dw	0
	db	0
inimsg_e:


;
;----------------------------------------------------------------------
;

sysram_init:
	ld hl,sysramw
	ld de,topcodsys
	ld bc,sysrame-sysramw
	ldir

	ret

;----------------------------------------------------------------------

ivtab_init:
	ld	hl,ivtab	;
	ld	a,h		;
	ld	i,a		;
	out0	(il),l		;

; Let all vectors point to spurious int routines.

	ld	d,high sp.int0
	ld	a,low  sp.int0
	ld	b,9
ivt_i1:
	ld	(hl),a
	inc	l
	ld	(hl),d
	inc	l
	add	a,sp.int.len
	djnz	ivt_i1
	ret

;----------------------------------------------------------------------

prt0_init:
	ld	a,i
	ld	h,a
	in0	a,(il)
	and	0E0h
	or	IV$PRT0
	ld	l,a
	ld	(hl),low  iprt0
	inc	hl
	ld	(hl),high iprt0
	ld	hl,prt0itab
	call	io.ini.m
	ret

prt0itab:
	db	prt0it_e-prt0itab-2
	db	tmdr0l
	dw	PRT_TC10MS
	dw	PRT_TC10MS
	db	M_TIE0+M_TDE0	;enable timer 0 interrupt and down count.
prt0it_e:


;
;----------------------------------------------------------------------
;

io.ini:
	push	bc
	ld	b,0		;high byte port adress
	ld	a,(hl)		;count
	inc	hl
ioi_1:
	ld	c,(hl)		;port address
	inc	hl
	outi
	inc	b		;outi decrements b
	dec	a
	jr	nz,ioi_1
	pop	bc
	ret

io.ini.m:
	push	bc
	ld	b,(hl)
	inc	hl
	ld	c,(hl)
	inc	hl
	otimr
	pop	bc
	ret

io.ini.l:
;

;----------------------------------------------------------------------
;

; compute crc
; hl: start adr
; bc: len
; bc returns crc val

do_crc16:
	ld	de,0FFFFh
crc1:
	ld	a,(hl)
	xor	e
	ld	e,a
	rrca
	rrca
	rrca
	rrca
	and	0Fh
	xor	e
	ld	e,a
	rrca
	rrca
	rrca
	push	af
	and	1Fh
	xor	d
	ld	d,a
	pop	af
	push	af
	rrca
	and	0F0h
	xor	d
	ld	d,a
	pop	af
	and	0E0h
	xor	e
	ld	e,d
	ld	d,a
	cpi
	jp	pe,crc1
	or	e		;z-flag
	ret


gencrc_alv:
	push hl			;03f6
	push de			;03f7
	push bc
	push af			;03f8
	ld hl,banktabsys	;03f9
	ld bc,crc_len		;03fc
	call do_crc16		;03ff
	ld (hl),e
	inc hl
	ld (hl),d
	pop af			;0406
	pop bc
	pop de			;0407
	pop hl			;0408
	ret			;0409

checkcrc_alv:
	push hl			;040a
	push de
	push bc			;040b
	ld hl,banktabsys	;040d
	ld bc,crc_len+2		;0410
	call do_crc16		;0413
	pop bc			;041d
	pop de
	pop hl			;041e
	ret			;041f

;----------------------------------------------------------------------

;
;  alloc
;
;	h:	max bank #
;	l:	min bank #
;	b:	max size
;	c:	min size
;
;    ret:
;	a: 	0  == ok
;		1  ==
;		2  == no bank # in requested range
;		ff == crc error
;

sub_0420h:
	call checkcrc_alv	;0420
	jr nz,l049ch		;0424	crc error, tables corrupt

	call sub_049dh		;0427	bank # in req. range available?
	jr c,l0499h		;042a
	push ix			;042c
	push iy			;042e
	push de			;0430
	push hl			;0431
	push bc			;0432
	ld c,b			;0433
	ld b,alv_len+1		;0434
	ld d,0			;0436
	ld hl,memalv-1		;0438
	jr l0441h		;043b

; find free blocks

l043dh:
	ld a,(hl)		;043d
	inc a			;043e	free blocks are marked 0ffh
	jr z,l0446h		;043f
l0441h:
	inc hl			;0441
	djnz l043dh		;0442
	jr l0464h		;0444
l0446h:
	push hl			;0446
	pop ix			;0447	free blocks start here
	ld e,000h		;0449
	jr l0451h		;044b
l044dh:				;	count free blocks
	ld a,(hl)		;044d
	inc a			;044e
	jr nz,l0457h		;044f
l0451h:
	inc e			;0451
	inc hl			;0452
	djnz l044dh		;0453
	jr l0464h		;0455

; end of free blocks run.

l0457h:
	ld a,d			;0457
	cp e			;0458	nr of blocks >= requested ?
	jr nc,l0441h		;0459

	ld d,e			;045b
	push ix			;045c
	pop iy			;045e
	ld a,d			;0460
	cp c			;0461
	jr c,l0441h		;0462
l0464h:
	pop bc			;0464
	ld a,d			;0465
	cp b			;0466
	jr c,l046ch		;0467
	ld d,b			;0469
	jr l0471h		;046a
l046ch:
	cp c			;046c
	jr nc,l0471h		;046d
	ld d,000h		;046f
l0471h:
	ld a,d			;0471
	push iy			;0472
	pop hl			;0474
	ld de,memalv		;0475
	or a			;0478
	sbc hl,de		;0479
	ld b,l			;047b
	ld c,a			;047c
	pop hl			;047d
l047eh:
	or a			;047e
	jr z,l0489h		;047f
	ld (iy+0),l		;0481
	inc iy			;0484
	dec a			;0486
	jr l047eh		;0487
l0489h:
	pop de			;0489
	pop iy			;048a
	pop ix			;048c
	call gencrc_alv		;048e
	ld a,c			;0491
	or a			;0492
	ld a,000h		;0493
	ret nz			;0495
	or 001h			;0496
	ret			;0498

l0499h:
	ld a,2			;0499
l049ch:
	or a
	ret			;049c


; search a free bank number in range
;	h: max #
;	l: min #
;    ret:
;	l: bank number available
;	nc, if found, bank nr. in l
;	cy, if none found

sub_049dh:
	push de			;049d
	push bc			;049e
	ex de,hl		;049f
	dec e			;04a0
l04a1h:
	inc e			;04a1	test next #
	ld a,d			;04a2
	cp e			;04a3
	jr c,l04b1h		;04a4
	ld a,e			;04a6
	ld hl,memalv		;04a7
	ld bc,alv_len		;04aa
	cpir			;04ad	bank# allready allocated?
	jr z,l04a1h		;04af	if yes, search for next
l04b1h:
	ex de,hl		;04b1
	pop bc			;04b2
	pop de			;04b3
	ret			;04b4


sub_04b5h:
	ld a,l			;04b5
	cp 012h			;04b6
	ccf			;04b8
	ret c			;04b9
	push hl			;04ba
	ld hl,banktab		;04bb
	call add_hl_a
	ld (hl),b		;04c3
	call gencrc_alv		;04c4
	pop hl			;04c7
	or a			;04c8	clear carry
	ret			;04c9


;--------------------------------------------------------------
;
; de: Log. Address
;  a: Bank number
;
;out ahl: Phys. (linear) Address


bnk2phys:
	push	hl
	ld	hl,banktab
	call	add_hl_a
	ld	a,(hl)
	pop	hl

	; fall thru
;--------------------------------------------------------------
;
; de: Log. Address
;  a: Bank (bbr)
;
; OP: ahl = (a<<12) + (d<<8) + e
;
;out ahl: Phys. (linear) Address


log2phys:
	push	bc		;
	ld	c,a		;
	ld	b,16		;
	mlt	bc		;bc = a<<4
	ld	l,d		;
	ld	h,0		;
	add	hl,bc		;bc + d == a<<4 + d
	ld	a,h		;
	ld	h,l		;
	ld	l,e		;
	pop	bc		;
	ret			;


;--------------------------------------------------------------
;
;return:
; hl = hl + a
; Flags undefined
;

add_hl_a:
	add a,l
	ld l,a
	ret nc
	inc h
	ret

; ---------------------------------------------------------

sysramw:

	.phase isvsw_loc
topcodsys:

; Trampoline for interrupt routines in banked ram.
; Switch stack pointer to "system" stack in top ram
; Save cbar

isv_sw:				;
	ex (sp),hl		;	save hl, return adr in hl
	push de			;
	push af			;
	ex de,hl		;
	ld hl,0			;
	add hl,sp		;
	ld a,h			;
	cp 0f8h			;
	jr nc,isw_1		;
	ld sp,$stack		;
isw_1:
	push hl			;
	in0 h,(cbar)		;
	push hl			;
	ld a,SYS$CBAR		;
	out0 (cbar),a		;
	ex de,hl		;
	ld e,(hl)		;
	inc hl			;
	ld d,(hl)		;
	ex de,hl		;
	push bc			;
	call jphl		;

	pop bc			;
	pop hl			;
	out0 (cbar),h		;
	pop hl			;
	ld sp,hl		;
	pop af			;
	pop de			;
	pop hl			;
	ei			;
	ret			;
jphl:
	jp (hl)			;

; ---------------------------------------------------------


iprt0:
	push	af
	push	hl
	in0	a,(tcr)
	in0	a,(tmdr0l)
	in0	a,(tmdr0h)
	ld	a,(tim_ms)
	inc	a
	cp	100
	jr	nz,iprt_1
	xor	a
	ld	hl,(tim_s)
	inc	hl
	ld	(tim_s),hl
iprt_1:
	ld	(tim_ms),a
	pop	hl
	pop	af
	ei
	ret

; ---------------------------------------------------------

sp.int0:
	ld	a,0d0h
	jr	sp.i.1
sp.int.len equ	$-sp.int0
	ld	a,0d1h
	jr	sp.i.1
	ld	a,0d2h
	jr	sp.i.1
	ld	a,0d3h
	jr	sp.i.1
	ld	a,0d4h
	jr	sp.i.1
	ld	a,0d5h
	jr	sp.i.1
	ld	a,0d6h
	jr	sp.i.1
	ld	a,0d7h
	jr	sp.i.1
	ld	a,0d8h
sp.i.1:
;	out	(80h),a
	halt

curph	defl	$
	.dephase
sysrame:
	.phase curph
tim_ms:	db	0
tim_s:	dw	0
	.dephase

;-----------------------------------------------------

	dseg

	ds	1
banktabsys:
	ds	1	;0c001h
	ds	1	;0c002h
banktab:
	ds	BANKS	;0c003h
memalv:
	ds	512/4		;Number of 4k blocks
alv_len	equ	$-memalv
crc_len	equ	$-banktabsys

crc_memalv:
	ds	2	;

	cseg

	;.phase	0ffc0h
;ivtab	equ	0ffc0h		; 0ffc0h	;int vector table
	;.dephase

	;.phase	0fffch
mark_55AA equ 0fffch
	;ds	4		; 0fffch
	;.dephase


	end