;
;	File:		MMUEqu.a
;
;	Contains:	Equates relevant to the MMUs available in Macintoshes.
;
;	Written by:	Bob Herold
;
;	Copyright:	© 1988-1991, 1993 by Apple Computer, Inc., all rights reserved.
;
;	Change History (most recent first):
;
;	   <SM2>	  2/5/93	SAM		Added EMMU type for emulated MMUs.
;		 <7>	12/31/91	RB		Added writeProtectBit equate.
;		 <6>	 1/30/91	gbm		sab, #38: Change the ‘already including this file’ variable to
;									all uppercase (for security reasons)
;		 <4>	 2/20/90	CCH		Added theSRP field to MMUConfigInfo record.
;		 <3>	  1/5/90	BG		Clarification comments added to the *MMUConfigInfo* record
;									header and definitions.
;		 <2>	  1/2/90	BG		First pass at cleaning this up to deal with 68040 MMUs.  More is
;									needed.
;	   <1.1>	 5/14/89	rwh		added descrTypeMask. Apologies to all.
;	   <1.0>	 5/13/89	rwh		new today

	IF &TYPE('__INCLUDINGMMUEQU__') = 'UNDEFINED' THEN
__INCLUDINGMMUEQU__	SET	1

;-------------
; MMU Modes 
;-------------

;false32b  		EQU 		0 			; 24 bit mode
;true32b   		EQU 		1			; 32 bit mode


;-----
; MMU Configuration Info record
;-----
;	NOTE - this does not work well with the 68040, as it has FOUR Transparent Translation	<3>
;			registers: ITTO, ITT1, DTT0 and DTT1. Also, 'theCRP' is not 64 bits;  in fact,	<3>
;			there is no CRP register on the 040.  Instead, it and the SRP are replaced by	<3>
;			the SRP and URP (both 32 bits wide).  The TC register is only 16 bits wide on	<3>
;			the 040.  "This needs to be fixed."												<3>

MMUConfigInfo	RECORD	0				; MMU configuration info
theCRP			ds.l	1				;    start of the 64-bit CRP on 020/030's			<4>
theSRP			ds.l	1				;	 start of the 32-bit SRP on 040's				<4>
theTC			ds.l	1				;    the TC (Translation Control Register) value
										;	 (the lsw contains the TC on a 68040)			<3>
theTT0			ds.l	1				;    the {I}TT0 (Transparent Translation Reg 0) value
theTT1			ds.l	1				;    the {I}TT1 (Transparent Translation Reg 1) value
MMUInfoSize		equ		*-MMUConfigInfo	;    size of an MMU info record
				ENDR
			

;-----
; Possible MMU Types
;-----

NoMMU		equ		0		; No MMU chip present
HMMU		equ		1		; fake 24-bit mapper (in Mac II only)
MMB			equ		2		; --- no longer supported 
PMMU851		equ		3		; 68851 Paged Memory Management Unit (in Mac II only)
PMMU030		equ		4		; 68030 built-in Paged Memory Management Unit
PMMU040		equ		5		; 68040 built-in MMU											<2>
EMMU1		equ		6		; Emulated MMU Type 1 (Risc Emulator Based Systems)				<SM2>

;-----
; MMU Table equates
;-----

writeProtectBit	equ			2				; write protect bit in table entries	<7> rb

descrPage		equ			$01				; page descriptor type *** move these to MMUequ.a ***
descrTbl4		equ			$02				; short table type
descrTbl8		equ			$03				; long table type
descrTypeMask	equ			$03				; mask to get type field
LongStat		equ			$FC00			; status field for long table descriptors
LowLim			equ			$7FFF			; default lowest limit for long descriptors

	ENDIF	; ...already included