DIRECTORYPrincOpsUtils USING[ LongCOPY ],PrincOps USING[ BytePC, InstWord, op, zBRK ],VM USING[ PageNumberForAddress, MakeReadOnly, MakeReadWrite, PageNumber, State ],WorldVM USING[ Address, LocalWorld, World ],WVMPrivate USING[ GetPage, PageData, PageHandle, PageNumber, pageSize, ReleasePage, WriteAndReleasePage ];WVMImpl: MONITOR-- mutual exclusion on making code pages writable(!) --IMPORTS PrincOpsUtils, VM, WorldVM, WVMPrivateEXPORTS WorldVM, WVMPrivate =BEGINOPEN WorldVM;local: WorldVM.World = WorldVM.LocalWorld[];Read: PUBLIC PROC[world: World, addr: Address] RETURNS[ i: CARDINAL ] =BEGINn: WVMPrivate.PageNumber;w: [0..WVMPrivate.pageSize);h: WVMPrivate.PageHandle;d: REF WVMPrivate.PageData;IF world = localTHEN RETURN[LOOPHOLE[addr, LONG POINTER TO CARDINAL]^];[n, w, h, d] _ PageFromAddr[world, addr];i _ d[w];WVMPrivate.ReleasePage[h];END;Write: PUBLIC PROC[world: World, addr: Address, value: CARDINAL] =BEGINn: WVMPrivate.PageNumber;w: [0..WVMPrivate.pageSize);h: WVMPrivate.PageHandle;d: REF WVMPrivate.PageData;IF world = localTHEN { LOOPHOLE[addr, LONG POINTER TO CARDINAL]^ _ value; RETURN };[n, w, h, d] _ PageFromAddr[world, addr];d[w] _ value;WVMPrivate.WriteAndReleasePage[h];END;LongRead: PUBLIC PROC[world: World, addr: Address] RETURNS[ i: LONG CARDINAL ] =BEGINn: WVMPrivate.PageNumber;w: [0..WVMPrivate.pageSize);h: WVMPrivate.PageHandle;d: REF WVMPrivate.PageData;IF world = localTHEN RETURN[LOOPHOLE[addr, LONG POINTER TO LONG CARDINAL]^];[n, w, h, d] _ PageFromAddr[world, addr];IF w = WVMPrivate.pageSize-1THEN { WVMPrivate.ReleasePage[h]; CopyRead[world,addr,SIZE[LONG CARDINAL],@i] }ELSE BEGINi _ LOOPHOLE[@d[w],LONG POINTER TO LONG CARDINAL]^;WVMPrivate.ReleasePage[h];END;END;LongWrite: PUBLIC PROC[world: World, addr: Address, value: LONG CARDINAL] =BEGINn: WVMPrivate.PageNumber;w: [0..WVMPrivate.pageSize);h: WVMPrivate.PageHandle;d: REF WVMPrivate.PageData;IF world = localTHEN { LOOPHOLE[addr, LONG POINTER TO LONG CARDINAL]^ _ value; RETURN };[n, w, h, d] _ PageFromAddr[world, addr];IF w = WVMPrivate.pageSize-1THEN { WVMPrivate.ReleasePage[h];CopyWrite[world,@value,SIZE[LONG CARDINAL],addr] }ELSE BEGINLOOPHOLE[@d[w],LONG POINTER TO LONG CARDINAL]^ _ value;WVMPrivate.WriteAndReleasePage[h];END;END;CopyRead: PUBLIC PROC[world: World, from: Address, nwords: INT,to: LONG POINTER] =BEGINn: WVMPrivate.PageNumber;w: [0..WVMPrivate.pageSize);h: WVMPrivate.PageHandle;d: REF WVMPrivate.PageData;IF world = localTHEN { PrincOpsUtils.LongCOPY[from: LOOPHOLE[from], nwords: nwords, to: to]; RETURN };WHILE nwords > 0DO amount: (0..WVMPrivate.pageSize];[n, w, h, d] _ PageFromAddr[world, from];amount _ MIN[nwords,WVMPrivate.pageSize-w];PrincOpsUtils.LongCOPY[from: @d[w], to: to, nwords: amount];nwords _ nwords - amount; from _ from + amount; to _ to + amount;WVMPrivate.ReleasePage[h];ENDLOOP;END;CopyWrite: PUBLIC PROC[world: World, from: LONG POINTER, nwords: INT,to: Address] =BEGINn: WVMPrivate.PageNumber;w: [0..WVMPrivate.pageSize);h: WVMPrivate.PageHandle;d: REF WVMPrivate.PageData;IF world = localTHEN { PrincOpsUtils.LongCOPY[from: from, nwords: nwords, to: LOOPHOLE[to]]; RETURN };WHILE nwords > 0DO amount: [0..WVMPrivate.pageSize);[n, w, h, d] _ PageFromAddr[world, to];amount _ MIN[nwords,WVMPrivate.pageSize-w];PrincOpsUtils.LongCOPY[from: from, to: @d[w], nwords: amount];nwords _ nwords - amount; from _ from + amount; to _ to + amount;WVMPrivate.WriteAndReleasePage[h];ENDLOOP;END;PageFromAddr: PROC[world: WorldVM.World, addr: WorldVM.Address]RETURNS[n: WVMPrivate.PageNumber, w: [0..WVMPrivate.pageSize),h: WVMPrivate.PageHandle, d: REF WVMPrivate.PageData] =BEGINn _ addr / WVMPrivate.pageSize;w _ addr - n * LONG[WVMPrivate.pageSize];[d, h] _ WVMPrivate.GetPage[world, n];END;SetBreak: PUBLIC PROC[world: World, addr: Address, offset: PrincOps.BytePC]RETURNS[ oldByte: PrincOps.op ] =BEGINoldByte _ Patch[world, addr+offset/2, offset MOD 2, PrincOps.zBRK];IF oldByte = PrincOps.zBRK THEN ERROR IllegalPatch;END;ClearBreak: PUBLIC PROC[world: World, addr: Address,offset: PrincOps.BytePC,oldByte: PrincOps.op] =BEGINbrk: PrincOps.op = Patch[world, addr+offset/2, offset MOD 2, oldByte];IF brk # PrincOps.zBRK THEN ERROR IllegalPatch;END;IllegalPatch: PUBLIC ERROR = CODE;Patch: PUBLIC ENTRY PROC[world: World, addr: Address,offset: [0..1], byte: PrincOps.op]RETURNS[oldByte: PrincOps.op] =BEGINENABLE UNWIND => NULL;value: PrincOps.InstWord _ LOOPHOLE[Read[world, addr]]; -- new memory word contents --oldByte _ IF offset=0 THEN value.evenbyte ELSE value.oddbyte;IF offset=0 THEN value.evenbyte _ byte ELSE value.oddbyte _ byte;IF world = localTHEN BEGINptr: LONG POINTER = LOOPHOLE[addr];page: VM.PageNumber = VM.PageNumberForAddress[ptr];readOnly: BOOL = VM.State[page].readOnly;IF readOnly THEN VM.MakeReadWrite[[page: page, count: 1]];ptr^ _ value;IF readOnly THEN VM.MakeReadOnly[[page: page, count: 1]];ENDELSE BEGINn: WVMPrivate.PageNumber;w: [0..WVMPrivate.pageSize);h: WVMPrivate.PageHandle;d: REF WVMPrivate.PageData;[n, w, h, d] _ PageFromAddr[world, addr];d[w] _ LOOPHOLE[value];WVMPrivate.WriteAndReleasePage[h];END;END;END.   Ф  Cedar Remote Debugging: word-level implementationWVMImpl.mesaAndrew Birrell  August 1, 1983 12:57 pmPaul Rovner, August 10, 1983 12:05 pm Э╩Ц  Ш JЪЬ1Щ1JЪЬЩJЪЬ'Щ'JЪЬ%Щ%JШ Ъ╧k	Ш	JЪЬЭЬШ JЪЬ	ЭЬШ-JЪЭЬЭЬIШQJЪЬЭЬШ,JЪЬЭЬZШjЧJШ ЪЬ	Э╧c7ШGJЪЭЬЭЬШ.JЪЭЬШЧJШ JЪЭШJШ JЪЭЬ	ШJШ JШ,JШ Ъ
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