[z180-stamp-cpm3.git] / cbios / mm.180

	page	255
	.z80


	global mmuinit
	global bnk2log,bnk2phy,hwl2phy

	include config.inc
	include	z180reg.inc


;----------------------------------------------------------------------
; Memory Map:
;
;	Common	CAStart ...     0FFFF
;	Bank 0	  00000 ... CAStart-1
;	Bank 1    10000 ...
;	Bank 2
;
;----------------------------------------------------------------------

	cseg

mmuinit:
	ld	a,USR$CBAR
	out0	(cbar),a
	ret

;--------------------------------------------------------------------
; Return the BBR value for the given bank number
;
; in  a: Bank number
; out a: bbr value

bnk2log:
	or	a		;
	ret	z		; Bank 0 is at physical address 0

	dec	a
	push	bc		;
	ld	b,a		;
	ld	c,CA		;
	mlt	bc		; bank size * bank number
	ld	a,c		;
	add	a,10h		; add bank0 + common
	pop	bc		;
	ret			;

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

;in  hl: Log. Address
;     a: Bank number
;
;out ahl: Phys. (linear) Address


bnk2phy:
	push	bc
	ld	c,a
	ld	a,h
	and	a,0f0h
	cp	CA*16
	ld	a,c
	pop	bc

	jr	c,b2p_banked
	xor	a		; address is in common
	jr	b2b_cont	;    base is 0
b2p_banked:
	call	bnk2log		; get address base
b2b_cont:

	; fall thru

;--------------------------------------------------------------
;
; hl: Log. Address
;  a: Bank base (bbr)
;
;	     2           0       0
;	     0   6       8       0
; hl	          hhhhhhhhllllllll
;  a	+     bbbbbbbb
;
; OP: ahl = (a<<12) + (h<<8) + l
;
;out ahl: Phys. (linear) Address

log2phy:
	push	bc		;
l2p_i:
	ld	c,a		;
	ld	b,16		;
	mlt	bc		; bc = a<<4
	ld	a,c		;
	add	a,h		;
	ld	h,a		;
	ld	a,b		;
	adc	a,0		;
	pop	bc		;
	ret			;

;--------------------------------------------------------------
;
; de: Log. Address
;
;
; OP: ahl = (bankbase<<12) + (d<<8) + e
;
;out ahl: Phys. (linear) Address


hwl2phy:
	push	bc		;
	in0	c,(cbar)	;
	ld	a,h		;
	or	00fh		; log. addr in common1?
	cp	c
	jr	c,hlp_1

	in0	a,(cbr)		; yes, cbr is address base
	jr	hl2p_x
hlp_1:
	ld	b,16		; log. address in baked area?
	mlt	bc
	ld	a,h
	cp	c
	jr	c,hlp_2
	in0	a,(bbr)		; yes, bbr is address base
	jr	hl2p_x
hlp_2:
	xor	a		; common1
hl2p_x:
	jr	nz,l2p_i

	pop	bc		; bank part is 0, no translation
	ret			;


;--------------------------------------------------------------
; Trampoline for routines in banked ram.
; Switch stack pointer to "system" stack in top ram
; Save cbar
;
	extrn	bs$stack

	cseg	; common!

	public	_b0call
_b0call:

	ld	(b0_save_hl),hl
	ld	(b0_save_de),de
	push	af
	pop	hl
	ld	(b0_save_af),hl

	pop	de			;get ptr to 'function address' in de
	ld	hl,2
	add	hl,de
	push	hl			;put return address on stack

   if 0 ; link80

	ld	hl,0
	add	hl,sp			;
	ld	a,h
	cp	high (bs$stack-bs$stack$size) ;link80 can't process this
	jr	nc,$ + 5		;skip if stack allready in common bios ram

   else

	ld	hl,bs$stack-bs$stack$size
	ld	a,h
	dec	a
	ld	hl,0
	add	hl,sp			;
	cp	h
	jr	c,$ + 5			;skip if stack allready in common bios ram
   endif
	ld	sp,bs$stack		;

	push	hl			;save	user stack pointer
	in0	h,(cbar)		;
	push	hl			;
	ld	hl,b0c_ret
	push	hl
	ld	a,SYS$CBAR		;
	out0	(cbar),a		;
	ex	de,hl			;ptr
	ld	e,(hl)			;get 'function address'
	inc	hl			;
	ld	d,(hl)			;
	push	de			;put on (switched) stack

	ld	hl,(b0_save_af)		;get back users registers
	push	hl
	pop	af
	ld	de,(b0_save_de)
	ld	hl,(b0_save_hl)
	ret				;go to function
b0c_ret:
	ld	(b0_save_hl),hl

	pop	hl			;
	out0	(cbar),h		;
	pop	hl			;
	ld	sp,hl			;
	ld	hl,(b0_save_hl)
	ret				;


b0_save_hl: dw	0
b0_save_de: dw	0
b0_save_af: dw	0


;====================================================================

  if 0

;--------------------------------------------------------------------
; Return the BBR value for the given bank number

bnk2bbr:
	or	a		; 4
	ret	z		; 5/10 | 11		14

	push	bc		;11 | 11
	ld	b,a		; 4
	ld	c,CA		; 6
	mlt	bc		;17			    >45
	ld	a,c		; 4
	add	a,10h		; 6
	pop	bc		; 9 | 10
	ret			; 9 | 10		76

	push	ix		;2 / 14 | 15
	ld	ix,bnktbl	;4 / 12 | 14
	ld	($+3+2),a	;3 / 15 | 19
	ld	a,(ix+0)	;3 / 14 | 19
	pop	ix		;2 / 12 | 14
	ret			;1 /  9 | 10		15 / 76|91

	push	hl		;1 / 11 | 11
	ld	hl,bnktbl	;3 /  9 | 10
	add	a,l		;1 /  4 | 4
	ld	l,a		;1 /  4 | 4
	ld	a,0		;1 /  6 | 7
	adc	a,h		;1 /  4 | 4
	ld	h,a		;1 /  4 | 4
	ld	a,(hl)		;1 /  6 | 7
	pop	hl		;1 /  9 | 10
	ret			;1 /  9 | 10		12 / 66|71

	push	hl		;1 / 11 | 11
	add	a,low bnktbl	;2 /  6 | 7
	ld	l,a		;1 /  4 | 4
	ld	a,0		;1 /  6 | 7
	adc	a,high bnktbl	;2 /  6 | 7
	ld	h,a		;1 /  4 | 4
	ld	a,(hl)		;1 /  6 | 7
	pop	hl		;1 /  9 | 10
	ret			;1 /  9 | 10		11 / 61|67

  endif


	end
Commit	Line	Data
ea5293bb L	1	page 255
	2	.z80
	3
	4
	5	global mmuinit
	6	global bnk2log,bnk2phy,hwl2phy
	7
	8	include config.inc
	9	include z180reg.inc
	10
	11
	12	;----------------------------------------------------------------------
	13	; Memory Map:
	14	;
	15	; Common CAStart ... 0FFFF
	16	; Bank 0 00000 ... CAStart-1
	17	; Bank 1 10000 ...
	18	; Bank 2
	19	;
	20	;----------------------------------------------------------------------
	21
	22	cseg
	23
	24	mmuinit:
	25	ld a,USR$CBAR
	26	out0 (cbar),a
	27	ret
	28
	29	;--------------------------------------------------------------------
	30	; Return the BBR value for the given bank number
	31	;
	32	; in a: Bank number
	33	; out a: bbr value
	34
	35	bnk2log:
	36	or a ;
	37	ret z ; Bank 0 is at physical address 0
	38
	39	dec a
	40	push bc ;
	41	ld b,a ;
	42	ld c,CA ;
	43	mlt bc ; bank size * bank number
	44	ld a,c ;
	45	add a,10h ; add bank0 + common
	46	pop bc ;
	47	ret ;
	48
	49	;--------------------------------------------------------------
	50
	51	;in hl: Log. Address
	52	; a: Bank number
	53	;
	54	;out ahl: Phys. (linear) Address
	55
	56
	57	bnk2phy:
1d26b866 L	58	push bc
	59	ld c,a
	60	ld a,h
	61	and a,0f0h
	62	cp CA*16
	63	ld a,c
	64	pop bc
	65
	66	jr c,b2p_banked
	67	xor a ; address is in common
	68	jr b2b_cont ; base is 0
	69	b2p_banked:
	70	call bnk2log ; get address base
	71	b2b_cont:
	72
ea5293bb L	73	; fall thru
	74
	75	;--------------------------------------------------------------
	76	;
	77	; hl: Log. Address
	78	; a: Bank base (bbr)
	79	;
	80	; 2 0 0
	81	; 0 6 8 0
	82	; hl hhhhhhhhllllllll
	83	; a + bbbbbbbb
	84	;
	85	; OP: ahl = (a<<12) + (h<<8) + l
	86	;
	87	;out ahl: Phys. (linear) Address
	88
	89	log2phy:
	90	push bc ;
	91	l2p_i:
	92	ld c,a ;
	93	ld b,16 ;
	94	mlt bc ; bc = a<<4
	95	ld a,c ;
	96	add a,h ;
	97	ld h,a ;
	98	ld a,b ;
	99	adc a,0 ;
	100	pop bc ;
	101	ret ;
	102
	103	;--------------------------------------------------------------
	104	;
	105	; de: Log. Address
	106	;
	107	;
	108	; OP: ahl = (bankbase<<12) + (d<<8) + e
	109	;
	110	;out ahl: Phys. (linear) Address
	111
	112
	113	hwl2phy:
	114	push bc ;
	115	in0 c,(cbar) ;
	116	ld a,h ;
	117	or 00fh ; log. addr in common1?
	118	cp c
	119	jr c,hlp_1
	120
	121	in0 a,(cbr) ; yes, cbr is address base
	122	jr hl2p_x
	123	hlp_1:
	124	ld b,16 ; log. address in baked area?
	125	mlt bc
	126	ld a,h
	127	cp c
	128	jr c,hlp_2
	129	in0 a,(bbr) ; yes, bbr is address base
	130	jr hl2p_x
	131	hlp_2:
	132	xor a ; common1
	133	hl2p_x:
	134	jr nz,l2p_i
	135
	136	pop bc ; bank part is 0, no translation
137	ret ;
138
139
b43b4662 L	140	;--------------------------------------------------------------
	141	; Trampoline for routines in banked ram.
	142	; Switch stack pointer to "system" stack in top ram
	143	; Save cbar
	144	;
	145	extrn bs$stack
	146
	147	cseg ; common!
	148
	149	public _b0call
	150	_b0call:
	151
	152	ld (b0_save_hl),hl
	153	ld (b0_save_de),de
	154	push af
	155	pop hl
	156	ld (b0_save_af),hl
	157
	158	pop de ;get ptr to 'function address' in de
	159	ld hl,2
	160	add hl,de
	161	push hl ;put return address on stack
	162
	163	if 0 ; link80
	164
	165	ld hl,0
	166	add hl,sp ;
	167	ld a,h
	168	cp high (bs$stack-bs$stack$size) ;link80 can't process this
	169	jr nc,$ + 5 ;skip if stack allready in common bios ram
	170
	171	else
	172
	173	ld hl,bs$stack-bs$stack$size
	174	ld a,h
	175	dec a
	176	ld hl,0
	177	add hl,sp ;
	178	cp h
	179	jr c,$ + 5 ;skip if stack allready in common bios ram
	180	endif
	181	ld sp,bs$stack ;
	182
	183	push hl ;save user stack pointer
	184	in0 h,(cbar) ;
	185	push hl ;
	186	ld hl,b0c_ret
	187	push hl
	188	ld a,SYS$CBAR ;
	189	out0 (cbar),a ;
	190	ex de,hl ;ptr
	191	ld e,(hl) ;get 'function address'
	192	inc hl ;
	193	ld d,(hl) ;
	194	push de ;put on (switched) stack
	195
	196	ld hl,(b0_save_af) ;get back users registers
	197	push hl
	198	pop af
	199	ld de,(b0_save_de)
	200	ld hl,(b0_save_hl)
	201	ret ;go to function
	202	b0c_ret:
	203	ld (b0_save_hl),hl
204
205	pop hl ;
206	out0 (cbar),h ;
207	pop hl ;
208	ld sp,hl ;
209	ld hl,(b0_save_hl)
210	ret ;
211
212
213	b0_save_hl: dw 0
214	b0_save_de: dw 0
215	b0_save_af: dw 0
216
217
218
ea5293bb L	219	;====================================================================
	220
	221	if 0
	222
	223	;--------------------------------------------------------------------
	224	; Return the BBR value for the given bank number
	225
	226	bnk2bbr:
	227	or a ; 4
	228	ret z ; 5/10 \| 11 14
	229
	230	push bc ;11 \| 11
	231	ld b,a ; 4
	232	ld c,CA ; 6
	233	mlt bc ;17 >45
	234	ld a,c ; 4
	235	add a,10h ; 6
	236	pop bc ; 9 \| 10
	237	ret ; 9 \| 10 76
	238
	239	push ix ;2 / 14 \| 15
	240	ld ix,bnktbl ;4 / 12 \| 14
	241	ld ($+3+2),a ;3 / 15 \| 19
	242	ld a,(ix+0) ;3 / 14 \| 19
	243	pop ix ;2 / 12 \| 14
	244	ret ;1 / 9 \| 10 15 / 76\|91
	245
	246	push hl ;1 / 11 \| 11
	247	ld hl,bnktbl ;3 / 9 \| 10
	248	add a,l ;1 / 4 \| 4
	249	ld l,a ;1 / 4 \| 4
	250	ld a,0 ;1 / 6 \| 7
	251	adc a,h ;1 / 4 \| 4
	252	ld h,a ;1 / 4 \| 4
	253	ld a,(hl) ;1 / 6 \| 7
	254	pop hl ;1 / 9 \| 10
	255	ret ;1 / 9 \| 10 12 / 66\|71
	256
	257	push hl ;1 / 11 \| 11
	258	add a,low bnktbl ;2 / 6 \| 7
	259	ld l,a ;1 / 4 \| 4
	260	ld a,0 ;1 / 6 \| 7
	261	adc a,high bnktbl ;2 / 6 \| 7
	262	ld h,a ;1 / 4 \| 4
	263	ld a,(hl) ;1 / 6 \| 7
	264	pop hl ;1 / 9 \| 10
	265	ret ;1 / 9 \| 10 11 / 61\|67
	266
	267	endif
	268
	269
	270	end