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Vmem
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vmemsupp.a
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1991-12-19
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**
** VMEM - a virtual memory manager for the Amiga operating system
**
** Version 0.1 ©1990 by Edward Hutchins
** Based in part on the SetCPU program by Dave Haynie
** Authors:
**
** Edward Hutchins: eah1@cec1.wustl.edu
** Loren Rittle: l-rittle@uiuc.edu
**
** Revisions:
** 12/19/91 code released as freeware under the GNU general public license - Ed.
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 1, or (at your option)
** any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
CSECT code
**
** Global variables from VMEM.C
**
XREF _PhysicalPages ; UWORD
XREF _VirtualPages ; UWORD
XREF _ROMBase ; APTR
XREF _PhysBase ; APTR
XREF _PageTable ; PD_SHORT * (ULONG)
XREF _PhysPageDesc ; PHYS_DESC * (UBYTE)
XREF _SysBusErrHandler ; *()
XREF _PageDaemonTask ; struct Task *
XREF _PageDaemonSig ; ULONG
XREF _FastMemHeader ; struct MemHeader *
XREF _PageFaultList ; struct MinList
XREF _PendingPageFaults ; UWORD
**
** Exported functions in this module
**
XDEF _GetCPUType ; ID the CPU
XDEF _GetCACR ; Get 020/030 CACR register
XDEF _SetCACR ; Set 020/030 CACR register
XDEF _GetMMUType ; Returns the type of MMU
XDEF _GetCRP ; Gets MMU CRP register
XDEF _SetCRP ; Sets MMU CRP register
XDEF _GetTC ; Gets MMU TC register
XDEF _SetTC ; Gets MMU TC register
XDEF _GetFPUType ; Gets the FPU type
XDEF _InsertFaultHandler ; sets up the fault handler
XDEF _HandlePageFault ; make visible to the debugger
XDEF _RestartTask ; make visible to the debugger
**
** External functions
**
XREF _AbsExecBase
XREF _LVOFindTask
XREF _LVOAllocTrap
XREF _LVOFreeTrap
XREF _LVOAllocate
XREF _LVODeallocate
XREF _LVOAllocSignal
XREF _LVOFreeSignal
XREF _LVOSignal
XREF _LVOWait
XREF _LVOSupervisor
XREF _LVOForbid
XREF _LVOPermit
XREF _LVODisable
XREF _LVOEnable
**
** Macros & constants used herein...
**
CALLSYS macro *
jsr _LVO\1(A6)
endm
CIB_ENABLE equ 0
CIB_FREEZE equ 1
CIB_ENTRY equ 2
CIB_CLEAR equ 3
CIB_BURST equ 4
CDB_ENABLE equ 8
CDB_FREEZE equ 9
CDB_ENTRY equ 10
CDB_CLEAR equ 11
CDB_BURST equ 12
CDB_WALLOC equ 13
AFB_68030 equ 2
ATNFLGS equ $129
** mask off the vector information
SS_VECTOR equ $6
SS_FORMAT_MASK equ $F000
** short bus cycle fault stack frame (16 words)
SSF_SIZE equ $20
SSF_LSIZE equ $08 ; size in longwords
SSF_FORMAT equ $A000
SSF_SR equ $0
SSF_PC equ $2
SSF_VECTOR equ $6
SSF_SSR equ $A
SSF_PIPE_C equ $C
SSF_PIPE_B equ $E
SSF_DATA_ADDR equ $10
SSF_DOB equ $18
** long bus cycle fault stack frame (46 words)
LSF_SIZE equ $5C
LSF_LSIZE equ $17 ; size in longwords
LSF_FORMAT equ $B000
LSF_SR equ $0
LSF_PC equ $2
LSF_VECTOR equ $6
LSF_SSR equ $A
LSF_PIPE_C equ $C
LSF_PIPE_B equ $E
LSF_DATA_ADDR equ $10
LSF_DOB equ $18
LSF_STAGEB_ADDR equ $24
LSF_DIB equ $2C
** special status bits
SSTAT_FC equ $8000 ; fault on stage C of the instruction pipe
SSTAT_FB equ $4000 ; fault on stage B
SSTAT_RC equ $2000 ; stage C re-run
SSTAT_RB equ $1000 ; stage B re-run
SSTAT_DF equ $0100 ; data fault
SSTAT_RM equ $0080 ; read-modify-write cycle
SSTAT_RW equ $0040 ; read/write indicator
SSTAT_SIZE_MASK equ $0030 ; size of data transfer
** the size of a fault node - 1K
FAULTNODE_SIZE equ $400
FAULT_FRAME equ 80 ; Frame in FaultNode -> 8 + 15*4 + 4 + 4 + 4
**
** Need just a little more stuff
**
NOLIST
include "exec/execbase.i"
include "exec/tasks.i"
include "exec/lists.i"
LIST
***********************************************************************
**
** This section contains functions that identify and operate on CPU
** things.
**
***********************************************************************
;======================================================================
;
; This function returns the type of the CPU in the system as a
; longword: 68000, 68010, 68020, or 68030. The testing must be done
; in reverse order, in that any higher CPU also has the bits set for
; a lower CPU. Also, since 1.3 doesn't recognize the 68030, if I
; find the 68020 bit set, I always check for the presence of a
; 68030.
;
; This routine should be the first test routine called under 1.2
; and 1.3.
;
; ULONG GetCPUType();
;
;======================================================================
_GetCPUType:
movem.l a4/a5,-(sp) ; Save this register
move.l _AbsExecBase,a6 ; Get ExecBase
btst.b #AFB_68030,ATNFLGS(a6) ; Does the OS think an '030 is here?
beq.s 0$
move.l #68030,d0 ; Sure does...
movem.l (sp)+,a4/a5
rts
0$ btst.b #AFB_68020,ATNFLGS(a6) ; Maybe a 68020
bne.s 2$
btst.b #AFB_68010,ATNFLGS(a6) ; Maybe a 68010?
bne.s 1$
move.l #68000,d0 ; Just a measley '000
movem.l (sp)+,a4/a5
rts
1$ move.l #68010,d0 ; Yup, we're an '010
movem.l (sp)+,a4/a5
rts
2$ move.l #68020,d0 ; Assume we're an '020
lea 3$,a5 ; Get the start of the supervisor code
CALLSYS Supervisor
movem.l (sp)+,a4/a5
rts
3$ movec cacr,d1 ; Get the cache register
move.l d1,a4 ; Save it for a minute
bset.l #CIB_BURST,d1 ; Set the inst burst bit
bclr.l #CIB_ENABLE,d1 ; Clear the inst cache bit
movec d1,cacr ; Try to set the CACR
movec cacr,d1
btst.l #CIB_BURST,d1 ; Do we have a set burst bit?
beq.s 4$
move.l #68030,d0 ; It's a 68030
bset.b #AFB_68030,ATNFLGS(a6)
4$ move.l a4,d1 ; Restore the original CACR
movec d1,cacr
rte
;======================================================================
;
; This function returns the 68020/68030 CACR register. It assumes
; a 68020 or 68030 based system.
;
; ULONG GetCACR()
;
;======================================================================
_GetCACR:
move.l _AbsExecBase,a6 ; Get ExecBase
btst.b #AFB_68020,ATNFLGS(a6) ; Does the OS think an '020 is here?
bne.s 1$
moveq #0,d0 ; No CACR here, pal
rts
1$ move.l a5,-(sp) ; Save this register
lea 2$,a5 ; Get the start of the supervisor code
CALLSYS Supervisor
move.l (sp)+,a5 ; Give back registers
rts
2$ movec cacr,d0 ; Make CACR the return value
rte
;======================================================================
;
; This function sets the value of the 68020/68030 CACR register.
; It assumes a 68020 or 68030 based system.
;
; void SetCACR(cacr)
; ULONG cacr;
;
;======================================================================
_SetCACR:
move.l 4(sp),d0 ; New CACR is on stack
move.l _AbsExecBase,a6 ; Get ExecBase
btst.b #AFB_68020,ATNFLGS(a6) ; Does the OS think an '020 is here?
bne.s 1$
rts ; No CACR here, pal
1$ move.l a5,-(sp) ; Save this register
lea 2$,a5 ; Get the start of the supervisor code
CALLSYS Supervisor
move.l (sp)+,a5 ; Give back register
rts
2$ movec d0,cacr ; Set the CACR
rte
***********************************************************************
**
** Functions that identify and operate on MMU things.
**
***********************************************************************
;======================================================================
;
; This function returns 0L if the system contains no MMU,
; 68851L if the system does contain an 68851, or 68030L if the
; system contains a 68030.
;
; This routine seems to lock up on at least some CSA 68020
; boards, though it runs just fine on those from Ronin and
; Commodore, as well as all 68030 boards it's been tested on.
;
; ULONG GetMMUType()
;
;======================================================================
_GetMMUType:
move.l _AbsExecBase,a6 ; Get ExecBase
movem.l a3/a4/a5,-(sp) ; Save this stuff
moveq #0,d0
move.l d0,a1
CALLSYS FindTask ; Call FindTask(0L)
move.l d0,a3
move.l TC_TRAPCODE(a3),a4 ; Change the exception vector
move.l #2$,TC_TRAPCODE(a3)
subq.l #4,sp ; Let's try an MMU instruction
pmove tc,(sp)
cmpi #0,d0 ; Any MMU here?
beq.s 1$
btst.b #AFB_68030,ATNFLGS(a6) ; Does the OS think an '030 is here?
beq.s 1$
move.l #68030,d0
1$ addq.l #4,sp ; Return that local
move.l a4,TC_TRAPCODE(a3) ; Reset exception stuff
movem.l (sp)+,a3/a4/a5 ; and return the registers
rts
; This is the exception code. No matter what machine we're on,
; we get an exception. If the MMU's in place, we should get a
; privilige violation; if not, an F-Line emulation exception.
2$ move.l (sp)+,d0 ; Get Amiga supplied exception #
cmpi #11,d0 ; Is it an F-Line?
beq.s 3$ ; If so, go to the fail routine
move.l #68851,d0 ; We have MMU
addq.l #4,2(sp) ; Skip the MMU instruction
rte
3$ moveq.l #0,d0 ; It dinna woik,
addq.l #4,2(sp) ; Skip the MMU instruction
rte
;======================================================================
;
; This function returns the MMU CRP register. It assumes a 68020
; system with MMU, or a 68030 based system (eg, test for MMU before
; you call this, or you wind up in The Guru Zone). Note that the
; CRP register is two longwords long.
;
; void GetCRP(ULONG *)
;
;======================================================================
_GetCRP:
move.l 4(sp),a0 ; Pointer to the CRP storage area
move.l _AbsExecBase,a6 ; Get ExecBase
move.l a5,-(sp)
lea 2$,a5 ; Get the start of the supervisor code
CALLSYS Supervisor
move.l (sp)+,a5
rts
2$ pmove crp,(a0)
rte
;======================================================================
;
; This function sets the MMU CRP register. It assumes a 68020
; system with MMU, or a 68030 based system (eg, test for MMU before
; you call this, or you wind up in The Guru Zone). Note that the
; CRP register is two longwords long.
;
; void SetCRP(ULONG *)
;
;======================================================================
_SetCRP:
move.l 4(sp),a0 ; Pointer to the CRP storage area
move.l _AbsExecBase,a6 ; Get ExecBase
move.l a5,-(sp)
lea 2$,a5 ; Get the start of the supervisor code
CALLSYS Supervisor
move.l (sp)+,a5 ; Give back registers
rts
2$ pflusha ; explicitly flush the ATC for now
pmove (a0),crp
rte
;======================================================================
;
; This function returns the MMU TC register. It assumes a 68020
; system with MMU, or a 68030 based system (eg, test for MMU before
; you call this, or you wind up in The Guru Zone).
;
; ULONG GetTC()
;
;======================================================================
_GetTC:
move.l _AbsExecBase,a6 ; Get ExecBase
move.l a5,-(sp)
subq.l #4,sp ; Make a place to dump TC
move.l sp,a0
lea 2$,a5 ; Get the start of the supervisor code
CALLSYS Supervisor
move.l (sp),d0 ; Here's the result
addq.l #4,sp
move.l (sp)+,a5
rts
2$ pmove tc,(a0)
rte
;======================================================================
;
; This function sets the MMU TC register. It assumes a 68020
; system with MMU, or a 68030 based system (eg, test for MMU before
; you call this, or you wind up in The Guru Zone).
;
; void SetTC(ULONG)
;
;======================================================================
_SetTC:
lea 4(sp),a0 ; Get address of our new TC value
move.l _AbsExecBase,a6 ; Get ExecBase
move.l a5,-(sp)
lea 2$,a5 ; Get the start of the supervisor code
CALLSYS Supervisor
move.l (sp)+,a5
rts
2$ pflusha ; explicitly flush the ATC for now
pmove (a0),tc
rte
***********************************************************************
**
** This section contains functions that identify and operate on
** FPU things.
**
***********************************************************************
;======================================================================
;
; This function returns the type of the FPU in the system as a
; longword: 0 (no FPU), 68881, or 68882.
;
; ULONG GetFPUType();
;
;======================================================================
_GetFPUType:
move.l a5,-(sp) ; Save this register
move.l _AbsExecBase,a6 ; Get ExecBase
btst.b #AFB_68881,ATNFLGS(a6) ; Does the OS think an FPU is here?
bne.s 1$
moveq.l #0,d0 ; No FPU here, dude
move.l (sp)+,a5 ; Give back the register
rts
1$ lea 2$,a5 ; Get the start of the supervisor code
CALLSYS Supervisor
move.l (sp)+,a5 ; Give back registers
rts
2$ move.l #68881,d0 ; Assume we're a 68881
fsave -(sp) ; Test and check
moveq.l #0,d1
move.b 1(sp),d1 ; Size of this frame
cmpi #$18,d1
beq 3$
move.l #68882,d0 ; It's a 68882
3$ frestore (sp)+ ; Restore the stack
rte
***********************************************************************
**
** Here come the page fault exception handlers
**
***********************************************************************
;======================================================================
;
; InsertFaultHandler - trap the system buserr vector (VBR + $
;
;======================================================================
_InsertFaultHandler:
move.l a5,-(sp) ; save a5
move.l _AbsExecBase,a6 ; get ExecBase
lea 1$,a5 ; get the start of the supervisor code
CALLSYS Supervisor
move.l (sp)+,a5 ; restore a5
rts
1$ movec VBR,a0 ; get the vector base register
lea 8(a0),a0 ; BUSERR exception vector
move.l (a0),_SysBusErrHandler ; save the current bus err handler
move.l #_HandlePageFault,(a0) ; install ourself
rte
;======================================================================
;
; HandlePageFault - determine whether a bus error was caused by
; a page fault, and handle it if it was.
; (for now, assume this is a page fault)
;
;======================================================================
_HandlePageFault:
movem.l d0-d7/a0-a6,-(sp) ; save registers on system stack
move.l _AbsExecBase,a6 ; Get ExecBase
CALLSYS Disable ; just to be sure
move.l _FastMemHeader,a0 ; allocate a fault node
move.l #FAULTNODE_SIZE,d0
CALLSYS Allocate
tst.l d0 ; did it work?
bne.s 1$
movem.l (sp)+,d0-d7/a0-a6 ; allocation failed, GURU time!
4$ move.l a0,-(sp) ; save a spot on the stack
move.l a0,-(sp) ; save the register
move.l _SysBusErrHandler,a0 ; normal bus error
move.l a0,4(sp) ; set the return address
move.l (sp)+,a0 ; restore register
rts ; jump to the big guru error
1$ move.l d0,a5 ; point at the memory block
add.l #FAULTNODE_SIZE,d0 ; point to the end of the node
move.l d0,a4 ; a4 is the fake user stack pointer
lea _PageFaultList,a0 ; where the faults are queued up
move.l a5,a1 ; this node
ADDTAIL ; add this FaultNode to the tail of the queue
addq.w #1,_PendingPageFaults ; count number of faults
lea 8(a5),a3 ; save the registers in the fault node
moveq #14,d0 ; number of registers - 1
2$ move.l (sp)+,(a3)+ ; copy a longword
dbra d0,2$ ; do it 15 times
move usp,a0 ; get the real user stack pointer
move.l a0,(a3)+ ; save it
move.l #_RestartTask,-(a4) ; put the fake return address on the stack
move a4,usp ; fake in the user stack pointer
moveq #0,d0
move.l d0,a1 ; NULL task name
CALLSYS FindTask ; find ourselves
move.l d0,(a3)+ ; save it
moveq #-1,d7 ; don't care which signal
move.l d7,d0
CALLSYS AllocSignal ; this is the wake up signal
cmp.l d0,d7 ; did we get one?
beq.s 4$ ; nope, GURU time!
move.l d0,d7 ; save this for later
move.b d0,(a3)+ ; save the signal number
addq.l #3,a3 ; padding
move.w SS_VECTOR(sp),d0 ; get the frame vector and type
andi.w #SS_FORMAT_MASK,d0 ; mask off the format bits
cmpi.w #SSF_FORMAT,d0 ; short?
bne.s 3$
moveq #SSF_LSIZE-1,d0 ; size in longwords - 1
bra.s 5$
3$ cmpi.w #LSF_FORMAT,d0 ; long?
bne 4$ ; GURU time again... (not a short branch)
moveq #LSF_LSIZE-1,d0 ; size in longwords - 1
5$ move.l (sp)+,(a3)+ ; copy the fault stack frame
dbra d0,5$
move.w #0,-(sp) ; create a fake exception frame
lea _LVOSignal(a6),a0 ; where to return to
move.l a0,-(sp) ; push it
move sr,d0 ; get the status register
andi.w #$DFFF,d0 ; clear the supervisor bit
move.w d0,-(sp) ; push the new status
move.l _PageDaemonTask,a1 ; the daemon to wake
move.l _PageDaemonSig,d0 ; signal to wake the daemon
rte ; do it!
;======================================================================
;
; RestartTask - restore the state information in the fault node,
; free the fault node, and restart the faulted task.
;
; on entry, a6 -> ExecBase, a5 -> FaultNode, d7 = WakeSigNum
;
;======================================================================
_RestartTask:
moveq.l #1,d0
lsl.l d7,d0 ; signal to wait for
CALLSYS Wait ; wait till we're paged in
move.l d7,d0 ; we no longer need the signal
CALLSYS FreeSignal
move.l a5,a4 ; Supervisor clobbers a5
lea 1$,a5 ; where to continue...
CALLSYS Supervisor ; drop into supervisor mode
1$ addq #8,sp ; pop the fake frame from the sys stack
move.l a4,a5 ; a5 -> FaultNode again
lea FAULT_FRAME(a5),a4 ; point at the fault frame
move.w SS_VECTOR(a4),d0 ; get the frame vector and type
andi.w #SS_FORMAT_MASK,d0 ; mask off the format bits
cmpi.w #SSF_FORMAT,d0 ; short?
bne.s 2$
moveq #SSF_LSIZE-1,d0 ; size in longwords - 1
lea SSF_SIZE(a4),a4 ; point at the end
bra.s 3$
2$ moveq #LSF_LSIZE-1,d0 ; assume long (size in longwords - 1)
lea LSF_SIZE(a4),a4 ; point at the end
3$ move.l -(a4),-(sp) ; copy the fault stack frame back
dbra d0,3$
subq.l #8,a4 ; skip SigNum and Task *
move.l -(a4),a0 ; real user stack pointer
move a0,usp ; fix the user stack
moveq #14,d0 ; number of registers - 1
4$ move.l -(a4),-(sp) ; copy the saved registers (FPx are ok)
dbra d0,4$
move.l _FastMemHeader,a0 ; free the fault node (we're unlinked)
move.l a5,a1 ; the node address
move.l #FAULTNODE_SIZE,d0 ; how big it is
CALLSYS Deallocate
pflusha ; flush all ATC registers for now...
CALLSYS Enable ; turn multitasking back on
movem.l (sp)+,d0-d7/a0-a6 ; restore the registers
rte ; and we're off!
end