supermario/base/SuperMarioProj.1994-02-09/OS/MMU/MMUPatches.a

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;
; File: MMUPatches.a
;
; Contains: patches to the MMU traps (the only one I know is SwapMMUMode)
;
; Copyright: © 1990, 1992 by Apple Computer, Inc., all rights reserved.
;
; Change History (most recent first):
;
; <5> 7/15/92 DTY #1036002 <gbm>: The InstallSwapPMMU should only be installed in
; 24 bit mode. Normally, always installing this on a Mac II is OK,
; since the Mac II normally only works in 24 bit mode. However,
; with Scruffy, the Mac II could be in 32 bit mode, and in this
; case, this InstallProc shouldnt be executed.
; <4> 2/12/92 JSM Moved this file to MMU folder, keeping all the old revisions.
; <3> 10/8/90 JDR change hasPMMUNoVM to hasPMMU and notVM
; <2> 8/18/90 dba put SwapHMMU and SwapPMMU in here
; <1> 8/2/90 dba first checked in
;
load 'StandardEqu.d'
include 'HardwarePrivateEqu.a'
include 'MMUEqu.a'
include 'LinkedPatchMacros.a'
;————————————————————————————————————————————————————————————————————————————————————————————————————
; SwapMMUMode — version for 24-bit only machines
machine mc68000
DontDoMuchSwappingOfTheMMUMode PatchProc _SwapMMUMode,(Plus,SE,Portable)
moveq #0,d0
rts
EndProc
;————————————————————————————————————————————————————————————————————————————————————————————————————
; SwapMMUMode — version for the II with HMMU
machine mc68020
ROMs II,hasHMMU,notAUX
MakePatch SwapHMMU,jSwapMMU
MakePatch SwapHMMU,_SwapMMUMode
; SwapHMMU - switches HMMU between 24 & 32 bit modes.
;
; This patch fixes the problems of losing sound interrupts when switching
; MMU modes. On HMMU Mac IIs, a bit on Via2 portB switches the MMU mode.
; Unfortunately, hitting this bit clears the CB1 interrupt flag, which is
; the ASC interrupt.
;
; Since the interrupt handlers all call SwapMMUMode to switch into 24 bit mode
; before processing interrutps, an ASC interrupt that occurs after the
; original interrupt could be lost.
;
; This patch reduces the window for losing ASC interrupts to the minimum
; possible, which is half an instruction. After switching MMU modes,
; it checks the ASCs interrupt register, and if any interrupts are present
; (but lost because the CB1 flag was cleared), it ORs the interrupt register back
; to itself. The ASC then generates a new interrupt.
;
; Entry
; d0.b 0 to set 24-bit mode, non-zero to set 32-bit mode.
;
; Exit
; MMU32Bit updated with passed value of d0
; d0.l has previous value of MMU32Bit
; MMU is switched into the desired mode
;
; Trashes:
; d1/a0
SwapHMMU Proc Export
if &type('vBase2') = 'UNDEFINED' then
vBase2: equ $50F02000 ; this Proc is for the Macintosh II only
endif
if &type('AscInt') = 'UNDEFINED' then
AscInt: equ $804 ; offset to ASCs interrupt register
endif
move.b d0,d1 ; check what mode desired, save it
bne.s @to32 ; IF we want 24 bit mode
moveq #0,d0 ; clear return register
move.b MMU32bit,d0 ; see what mode were in now
beq.s @done ; IF in 32 bit mode now
move sr,-(sp) ; save current interrupt status
ori #HiIntMask,sr ; disable interrupts during switch
andi.b #-1-(1<<vFC3),vBase2+vBufB;throw us into 24 bit mode
bra.s @common ; (re-use common code)
@to32 ; ELSE (we want 32 bit mode)
moveq #0,d0 ; clear return register
move.b MMU32bit,d0 ; see (and return) what mode were in now
bne.s @done ; IF in 24 bit mode now
move sr,-(sp) ; save current interrupt status
ori #HiIntMask,sr ; disable interrupts during switch
ori.b #1<<vFC3,VBase2+vBufB; throw us into 32 bit mode
@common move.b d1,MMU32Bit ; update global w/new mode flag
movec cacr,d1 ; get cache control register
ori.w #$0808,d1 ; set icache, dcache (in case) flush bits <1.1>
movec d1,cacr ; flush da cache, Guido
move.l ASCBase,a0 ; point to ASC
adda.w #AscInt,a0 ; point to ASC interrupt register
move.b (a0),d1 ; get ASC interrupt register
beq.s @doneASC ; IF ASC thinks interrupt is pending
tst.b vBase2+vier ; try to synch VIA so it catches the edge
or.b d1,(a0) ; re-generate interrupt to VIAs CB1
@doneASC ; ENDIF
move (sp)+,sr ; restore interrupt mask
; ENDIF
@done ; ENDIF
rts
EndProc
;————————————————————————————————————————————————————————————————————————————————————————————————————
; SwapMMUMode — version for the II with PMMU
machine mc68020
mc68851
ROMs II,hasPMMU,notVM,notAUX,using24BitHeaps
; This install code fills the MMUInfo table in from the existing MMU configuration.
;
; Possible optimizations of the MMU setup might be to use the tt0 & tt1 registers
; on 68030 based machines.
InstallSwapPMMU InstallProc
Import MMUInfo
With MMUConfigInfo
lea MMUInfo,a0 ; point at buffer for config info
pmove crp,theCRP(a0) ; get current 24 bit mode CRP
pmove tc,theTC(a0) ; get current 24 bit mode tc
moveq #true32b,d0 ; where were going
_SwapMMUMode ; switch to 32 bit mode
pmove crp,MMUInfoSize+theCRP(a0) ; get current 32 bit mode CRP
pmove tc,MMUInfoSize+theTC(a0) ; get current 32 bit mode tc
_SwapMMUMode ; go back to old mode
move sr,-(sp) ; save interrupt mask
ori #HiIntMask,sr ; no interrupts while changing lowmems
move.l a0,MMU24Info ; save ptr to 24 bit mode info
lea MMUInfoSize(a0),a0 ; point at 32 bit mode info
move.l a0,MMU32Info ; save ptr to 32 bit mode info
move (sp)+,sr ; restore interrupt mask
rts
EndWith
EndProc
MakePatch SwapPMMU,jSwapMMU
MakePatch SwapPMMU,_SwapMMUMode
; SwapPMMU - switches PMMU between 24 & 32 bit modes.
;
; This patch is just a more efficient version of SwapMMUMode that ONLY deals with
; PMMUs. It eliminates the ROM versions overhead of checking for the HMMU.
;
; Entry
; d0.b 0 to set 24-bit mode, non-zero to set 32-bit mode.
;
; Exit
; MMU32Bit updated with passed value of d0
; d0.l has previous value of MMU32Bit
; MMU is switched into the desired mode
;
; Trashes:
; d1/a0
SwapPMMU Proc Export
Entry MMUInfo
With MMUConfigInfo
move.b d0,d1 ; check what mode we are going to, set up d1
bne.s @to32 ; IF we want 24 bit mode
moveq #0,d0 ; clear return register
move.b MMU32bit,d0 ; see what mode were in now
beq.s @endif ; IF in 32 bit mode now
move.l MMU24Info,a0 ; get ptr to 24 bit mode info
bra.s @swap ; go to common swap code
; ENDIF
@to32 ; ELSE (we want 32 bit mode)
moveq #0,d0 ; clear return register
move.b MMU32bit,d0 ; see what mode were in now
bne.s @endif ; IF in 24 bit mode
move.l MMU32Info,a0 ; get ptr to 32 bit mode info
@swap move sr,-(sp) ; save current interrupt status
ori #HiIntMask,sr ; disable interrupts during switch
pmove theCRP+2(a0),tc ; disable translation temporarily
pmove theCRP(a0),crp ; set crp
pmove theTC(a0),tc ; fire up the TC
move.b d1,MMU32Bit ; update global w/new mode flag
movec cacr,d1 ; get cache control register
ori.w #$0808,d1 ; set 'flush' bits
movec d1,cacr ; flush both caches
move (sp)+,sr ; restore interrupt mask
; ENDIF
@endif ; ENDIF
rts
MMUInfo dcb.l MMUInfoSize*2,0 ; place for MMU config info
EndWith
EndProc
;————————————————————————————————————————————————————————————————————————————————————————————————————
End