;ST-68017 source code - ported from Run68017 on the Amiga by Kamran Karimi
;X68-68017 source code - ported from ST_68017 on the Atari ST by Dan Hollis
;
;emulates 30.5 (!) 68020 instructions.
;
;Instructions: bra.l, extb.l, cas, pack, unpk, link.l, movec, rtd, moves,
;              move ccr,<ea>, trapcc, mulu.l, muls.l, divu.l, divs.l,
;              divul.l, divsl.l, cas2, chk.l, chk2, cmp2, bsr.l, bfchg
;              bftst, bfset, bfclr, bfextu, bfexts, bfffo, bfins,
;          (!) bcc.l (bcc.l is emulated only if branch is taken!)
;
;Only the emulated instructions can use new 68020 addressing modes.
;--------------------------------------------------------------------------
;Atari ST Version by Dan Hollis (dhollis@bitsink.UUCP)
;2/23/93 - Original port from Amiga
;2/26/93 - Added XBRA support and error checking
;Assembled with TurboASS 1.7.1 using a standard 1040ST.
;
;X68000 Version by Seisei Yamaguchi
;7/7/94 - Original port from Atari ST
;1/8/95 - Identifier changed from 'X617' to 'ST17' (same as ST version).
;Assembled with HAS 3.05 using a modified X68000 EXPERT (17.3MHz).
;Refer to Run68017.DOC for more information.


	cpu 68000

_b~xb_id	equ	'ST17'     ;Unique identifier. Keep 'ST17' for EMULATE.
*_b~xb_id	equ	'X617'
_vct_addrerr	equ	$c/4
_vct_IllInst	equ	$10/4

	xref	keepchk

	include	doscall.mac
	include	iocscall.mac
	include	const.h
	include	pspdef.h
	include	naw.mac

	text
	even

	include	KEEPED.S	;keeped routine


MYSIZE		equ	EndIllegal-KEEP_begin+500

*---------------------

Addr		equ	BeginAddr-KEEP_begin+PSPSIZ
Inst		equ	BeginIllegal-KEEP_begin+PSPSIZ
PATCH1		equ	baxb_oldvec-KEEP_begin+PSPSIZ
PATCH2		equ	bixb_oldvec-KEEP_begin+PSPSIZ

*  These routines are located after ">PART 'Address exception handler'"
*and ">PART 'Block Storage Space'" for Human68K by S.Yamaguchi.

begin:
	m	<clr.l -(sp)>,	<pea.l (a0)>,	<BSR keepchk>	*既に常駐しているか
	m	<addq.l	#8,sp>,	<move.b	d0,d7>

	M	<BSR CHECK_ARG>,	<tst.b __rflag>,	<bNE REMOVE>

*
*	常駐、または、文字列データ更新
*
keep:
		tst.b	d7
		bNE	error3

keepmain:
		lea.l	regsav(pc),a1
		movem.l	a0/sp,(a1)

		*pea     installit(PC)   ;Address of routine
                *move.w  #38,-(SP)       ;Supexec
                *trap    #14
                *addq.l  #6,SP           ;Fix stack
		m	sSUPER,	<BSR installit>, sUSER

                *cmpi.l  #1,error        ;Error occurred?
                *beq.s   crap_out        ;Yup, then exit without install

                *pea     title(PC)       ;Address of titlescreen
                **move.w  #$09,-(SP)      ;GEMDOS Print Line
                **trap    #1              ;Call GEMDOS
		*DOS	_PRINT
                *addq.l  #4,sp		*6,SP           ;Fix stack

		m	<pea title(pc)>,	<DOS _PRINT>
		pea.l	crlfms(pc)	*kpms1(pc)
print:
		DOS	_PRINT
		addq.l	#8,sp

                clr.w   -(SP)           ;Null word	*What is '+500' ? (From S.Y.)
                *move.l  #(EndIllegal-begin)+500,-(SP) ;Length of mem to protect
		move.l	#MYSIZE,-(sp)
                *move.w  #$31,-(SP)      ;Termres function
                *trap    #1              ;Call GEMDOS
		DOS	_KEEPPR

crap_out:       pea     error_title(PC) ;Address of error screen
                *move.w  #$09,-(SP)      ;GEMDOS Print Line
                *trap    #1              ;Call GEMDOS
		DOS	_PRINT
                addq.l  #4,sp		*6,SP           ;Fix stack

                *clr.w   -(SP)           ;GEMDOS term
                *trap    #1              ;Call GEMDOS
		DOS	_EXIT


                *>PART 'Install ST_68017'
*--------------------
installit:
                *movea.l $0C,A0          ;Check for previous installation
                **cmpi.l  #"ST17",-8(A0)  ;Already installed?
		*cmpi.l  #_b~xb_id,-8(A0)	;Already installed?
                *beq.s   no_install      ;Yup, then exit!

		pea.l	kbreak(pc)		*ON ERROR GOTO kbreak
		move.w	#_CTRLVC,-(sp)
		DOS	_INTVCS
		move.w	#_ERRJVC,(sp)
		DOS	_INTVCS
		addq.l	#6,sp

                *lea     $0C,A0
                *move.l  (A0),baxb_oldvec ;save original 'address error' vector
                *move.l  4(A0),bixb_oldvec ;save original illegal inst. vector

		move.w	#_vct_addrerr,-(sp)
		DOS	_INTVCG			*Get BEFORE vector
		move.l	d0,PATCH1(a0)
		addq.l	#2,sp

		move.w	#_vct_IllInst,-(sp)
		DOS	_INTVCG			*Get BEFORE vector
		move.l	d0,PATCH2(a0)
		addq.l	#2,sp

		kretry:

                *move.l  #BeginAddr,(A0) ;put our new routines in!
                *move.l  #BeginIllegal,4(A0)


		pea.l	Addr(a0)
		move.w	#_vct_addrerr,-(sp)
		DOS	_INTVCS
		addq.l	#6,sp

		pea.l	Inst(a0)
		move.w	#_vct_IllInst,-(sp)
		DOS	_INTVCS
		addq.l	#6,sp


	lea.l	donflg(pc),a1
	st.b	(a1)
                *clr.l   error           ;No error
	bra	kdone

kbreak:
	movem.l	regsav(pc),a0/sp
	lea.l	donflg(pc),a1
	tst.b	(a1)
	beq	kretry

kdone:
                rts

*no_install:     move.l  #1,error        ;installation failure (already installed)
*                rts
*                *ENDPART
*--------------------
REMOVE
                *movea.l $0C,A0			;Check for previous installation
		*cmpi.l  #_b~xb_id,-8(A0)	;Already installed?

	tst.b	d7
	beq	error1

	lea.l	Addr(a0),a1
	move.w	#_vct_addrerr,-(sp)
	DOS	_INTVCG
	cmp.l	a1,d0			*Is vector already changed by other program ?
	bne	error2

	lea.l	Inst(a0),a1
	move.w	#_vct_IllInst,-(sp)
	DOS	_INTVCG
	cmp.l	a1,d0			*Is vector already changed by other program ?
	bne	error2

	lea.l	regsav(pc),a1
	movem.l	a0/sp,(a1)

	pea.l	rretry(pc)
	move.w	#_CTRLVC,-(sp)
	DOS	_INTVCS
	move.w	#_ERRJVC,(sp)
	DOS	_INTVCS
	addq.l	#6,sp

rretry:
	move.l	PATCH1(a0),-(sp)
	move.w	#_vct_addrerr,-(sp)
	DOS	_INTVCS
	addq.l	#6,sp

	move.l	PATCH2(a0),-(sp)
	move.w	#_vct_IllInst,-(sp)
	DOS	_INTVCS
	addq.l	#6,sp

	pea.l	MPSIZ(a0)
	DOS	_MFREE
	addq.l	#4,sp

	st.b	donflg
	bra	rdone

rbreak:
	movem.l	regsav(pc),a0/sp
	tst.b	donflg
	beq	rretry

rdone:
	pea.l	__mes__removed(pc)
	DOS	_PRINT
	addq.l	#4,sp

	DOS	_EXIT

*-------------------
CHECK_ARG
	tst.b	(a2)+			*a2 is cmd line pointer at Human68K
	bEQ	EXIT__CHECK_ARG

arglp:
	BSR	skipsp
	tst.b	d0
	beq	EXIT__CHECK_ARG

	cmpi.b	#'-',d0
	beq	chkopt
	cmpi.b	#'/',d0
	beq	chkopt
	BRA	usage

EXIT__CHECK_ARG	RTS ()

chkopt:
	addq.l	#1,a2
	move.b	(a2)+,d0
	beq	usage
	ori.b	#$20,d0
	cmpi.b	#'r',d0
	seq	__rflag
	beq	EXIT__CHECK_ARG
	bra	usage
*--------
skipsp:
		move.b	(a2)+,d0
	cmpi.b	#' ',d0
	beq	skipsp
	cmpi.b	#7,d0	*tab
	beq	skipsp

	subq.l	#1,a2
RTS ( d0 )
*---------------------
*
*	エラー処理
*
error1:
	lea.l	__mes__no_keeped(pc),a0
	bra	@F
error2:
	lea.l	errms2(pc),a0
	bra	@F
error3:
	lea.l	error_title(pc),a0
	bra	@F
usage:
	lea.l	__mes__usage(pc),a0
	bra	@F

	@@:
	move.w	#STDERR,-(sp)
	pea.l	(a0)
	DOS	_FPUTS
	addq.l	#6,sp

	move.w	#1,-(sp)
	DOS	_EXIT2
*------------------------------

	data


__rflag	dc.b	0

                *>PART 'Text bits - title screen, etc'
					;'>PART' has the mean under TURBOASS
title:         * DC.B 27,'E',
		dc.b	$0D,$0A
                DC.B 27,'p | Emul68017 : The 680x0 emulator  | ',27,'q',$0D,$0A
                DC.B 27,'p| Original by Kamran Karimi (Amiga) |',27,'q'
		dc.b	'	Ported by Seisei Yamaguchi (X68000) v1.01',$0D,$0A
                DC.B 27,'p | Ported by Dan Hollis (Atari ST) | ',27,'q'
		dc.b	'	美術講師のメンソレさんお元気ですか',$0D,$0A,0

error_title:    DC.B 27,'E',$0D,$0A
                DC.B 27,'p |                                 | ',27,'q',$0D,$0A
                DC.B 27,'p|          <<<< ERROR >>>>          |',27,'q',$0D,$0A
                DC.B 27,'p |   Emul68017 already installed   | ',27,'q',$0D,$0A,0
                EVEN
                *ENDPART	;'ENDPART' has the mean on TURBOASS

__mes__no_keeped	dc.b	'まだ68017組み込まれてへんで',$d,$a,0
__mes__removed		dc.b	'68017の常駐を解除しました',$d,$a,0
errms2	dc.b	'Run68017以降に常駐したプログラムがある様です',CR,LF
	dc.b	'先にそのプログラムを常駐解除して下さい',CR,LF,EOS
__mes__usage		dc.b	'68017	機能:	68020の新設命令をemulateする'
			dc.b	'（オプションなしでの実行で常駐します）',$d,$a,0
crlfms:	.dc.b	CR,LF,EOS

	even
regsav:	.dc.l	0,0
donflg:	.dc.b	0

                END	begin	*Start address is `begin'