<<>>
<<SymbolSegment.mesa>>
    <<Copyright Ó 1985, 1986, 1987, 1988, 1991 by Xerox Corporation.  All rights reserved.>>
    <<Satterthwaite, June 10, 1986 3:03:34 pm PDT>>
<<Russ Atkinson (RRA) March 1, 1988 6:16:35 pm PST>>

        DIRECTORY
            Literals USING [ltTag, ltType, stTag, stType],
            MobDefs USING [VersionStamp],
            SmallCards,
            Symbols USING [ISEIndex, CTXIndex, ExtensionType, seTag, seType, htTag, htType, ssType, ctxType, mdType, bodyType],
            Table USING [Base, IndexRep, Selector],
            Tree USING [Link, treeTag, treeType];
SymbolSegment: DEFINITIONS = {
    OPEN SmallCards;

    VersionID: CARDINAL = 08140;

    Base: TYPE = Table.Base;

    <<symbol table extensions>>

        ExtRecord: TYPE = MACHINE DEPENDENT RECORD [
            type (0: 0..15): Symbols.ExtensionType[$value..$default],
            pad (0: 16..31): CARD16 ¬ 0,
            sei (0: 32..63): Symbols.ISEIndex,    -- the key
            tree (0: 64..95): Tree.Link];

        ExtIndex: TYPE = Base RELATIVE LONG POINTER TO ExtRecord;
        ExtFirst: ExtIndex = LOOPHOLE[Table.IndexRep[tag: 0, highBits:0, lowBits:0]];
        ExtNull: ExtIndex = LOOPHOLE[Table.IndexRep[tag: 0]];

    <<allocation codes>>

        treeType: Table.Selector = Tree.treeType;
        seType: Table.Selector = Symbols.seType;
        htType: Table.Selector = Symbols.htType;
        ssType: Table.Selector = Symbols.ssType;
        ctxType: Table.Selector = Symbols.ctxType;
        mdType: Table.Selector = Symbols.mdType;
        bodyType: Table.Selector = Symbols.bodyType;
        ltType: Table.Selector = Literals.ltType;
        stType: Table.Selector = Literals.stType;
        extType: Table.Selector = 9;
        atType: Table.Selector = 10;        -- atom and typeId table
        constType: Table.Selector = 11;

        Tables: TYPE = Table.Selector[treeType..constType];

        biases: ARRAY Tables OF CARD = [
            LOOPHOLE[Table.IndexRep[Tree.treeTag, 0, 0]],    -- 0    treeType
            LOOPHOLE[Table.IndexRep[Symbols.seTag, 0, 0]],    -- 1    seType
            LOOPHOLE[Table.IndexRep[Symbols.htTag, 0, 0]],    -- 2    htType
            LOOPHOLE[Table.IndexRep[0, 0, 0]],        -- 3    ssType
            LOOPHOLE[Table.IndexRep[0, 0, 0]],        -- 4    ctxType
            LOOPHOLE[Table.IndexRep[0, 0, 0]],        -- 5    mdType
            LOOPHOLE[Table.IndexRep[0, 0, 0]],        -- 6    bodyType
            LOOPHOLE[Table.IndexRep[Literals.ltTag, 0, 0]],    -- 7    ltType
            LOOPHOLE[Table.IndexRep[Literals.stTag, 0, 0]],    -- 8    stType
            LOOPHOLE[Table.IndexRep[0, 0, 0]],        -- 9    extType
            LOOPHOLE[Table.IndexRep[0, 0, 0]],        -- 10    atType
            LOOPHOLE[Table.IndexRep[0, 0, 0]]];        -- 11    constType

    <<symbol segment headers>>

        WordOffset: TYPE = CARD;
        BlockDescriptor: TYPE = MACHINE DEPENDENT RECORD [offset: WordOffset, size: CARD];

        STHeader: TYPE = MACHINE DEPENDENT RECORD [
            versionIdent: CARD,
            version: MobDefs.VersionStamp,
            creator: MobDefs.VersionStamp,
            sourceVersion: MobDefs.VersionStamp,
            definitionsFile: BOOL,
            extended: BOOL,
            pad1: Card14 ¬ 0,
            pad2: Card16 ¬ 0,
            directoryCtx, importCtx, outerCtx: Symbols.CTXIndex,
            hvBlock: BlockDescriptor,
            htBlock: BlockDescriptor,
            ssBlock: BlockDescriptor,
            outerPackBlock: BlockDescriptor,
            innerPackBlock: BlockDescriptor,
            constBlock: BlockDescriptor,
            seBlock: BlockDescriptor,
            ctxBlock: BlockDescriptor,
            mdBlock: BlockDescriptor,
            bodyBlock: BlockDescriptor,
            extBlock: BlockDescriptor,
            treeBlock: BlockDescriptor,
            litBlock: BlockDescriptor,
            sLitBlock: BlockDescriptor,
            epMapBlock: BlockDescriptor,
            spareBlock: BlockDescriptor,
            fgRelBase: CARD,    -- in bytes
            fgCount: CARD];    -- in bytes

    <<fine grain table header>>

        FGHeader: TYPE = MACHINE DEPENDENT RECORD [
            offset: WordOffset,
            length: Card16 ¬ 0,
            sourceFile: PACKED SEQUENCE maxLength: Card16 OF CHAR];

    <<fine grain table declarations>>

        SourceStep: CARDINAL = Card16.LAST;
        ObjectStep: CARDINAL = Card16.LAST;

        FGTEntry: TYPE = MACHINE DEPENDENT RECORD [
            deltaObject: Card16,
            deltaSource: Card16
            ];
        }.