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Annotation of 42BSD/bin/as/assyms.h, revision 1.1

1.1     ! root        1: /*
        !             2:  *     Copyright (c) 1982 Regents of the University of California
        !             3:  *     @(#)assyms.h 4.5 6/30/83
        !             4:  */
        !             5: /*
        !             6:  *     To speed up walks through symbols defined in a particular
        !             7:  *     segment, we buil up a table of pointers into the symbol table
        !             8:  *     and a table of delimiters for each segment.  The delimiter for
        !             9:  *     the particular segment points to the first word in that segment.
        !            10:  */
        !            11: 
        !            12: extern struct  symtab  **symptrs;              /*dynamically allocated*/
        !            13: extern struct  symtab  **symdelim[NLOC + NLOC + 1];
        !            14: extern struct  symtab  **symptrub;
        !            15: extern int     nsyms;                  /*number in the symbol table*/
        !            16: extern int     njxxx;                  /*the number of jxxx entries in the table*/
        !            17: extern int     nforgotten;             /*how many entries erroneously entered*/
        !            18: extern int     nlabels;                /*how many labels in the symbol table*/
        !            19: extern int     hshused;                /*how many hash slots used*/
        !            20: 
        !            21: #define SEGITERATE(segno, start, end, copointer, walkpointer, ubpointer, direction) \
        !            22:        for(copointer = start == 0? symdelim[segno]:start,\
        !            23:            ubpointer = end == 0 ? *symdelim[segno+1] : *(symdelim[segno]-1),\
        !            24:            walkpointer = *copointer;\
        !            25:            walkpointer != ubpointer;\
        !            26:            walkpointer = * direction copointer)
        !            27: 
        !            28: #define SYMITERATE(copointer, walkpointer) \
        !            29:        for(copointer = symptrs, \
        !            30:            walkpointer = *copointer; \
        !            31:            copointer < symptrub; \
        !            32:            walkpointer = * ++ copointer)
        !            33: /*
        !            34:  *     Symbols are allocated in non contiguous chunks by extending
        !            35:  *     the data area.
        !            36:  */
        !            37: 
        !            38: #define SYMDALLOP      200
        !            39: struct         allocbox{
        !            40:        struct          allocbox        *nextalloc;
        !            41:        struct          symtab          symslots[SYMDALLOP];
        !            42: };
        !            43: 
        !            44: /*
        !            45:  *     Names are allocated in a dynamically extensible string pool.
        !            46:  */
        !            47: struct strpool{
        !            48:        struct  strpool *str_next;
        !            49:        int             str_nalloc;
        !            50:        char            str_names[STRPOOLDALLOP];
        !            51: };
        !            52: 
        !            53: extern struct  strpool *strplhead;
        !            54: 
        !            55: extern struct  allocbox        *allochead;
        !            56: extern struct  allocbox        *alloctail;
        !            57: extern struct  symtab          *nextsym;
        !            58: extern struct  allocbox        *newbox;
        !            59: extern char                    *namebuffer;
        !            60: extern int                     symsleft;
        !            61: 
        !            62: #define ALLOCQTY       sizeof (struct allocbox)
        !            63: /*
        !            64:  *     Iterate through all symbols in the symbol table in declaration
        !            65:  *     order
        !            66:  */
        !            67: #define DECLITERATE(allocwalk, walkpointer, ubpointer) \
        !            68:        for(allocwalk = allochead; \
        !            69:            allocwalk != 0; \
        !            70:            allocwalk = allocwalk->nextalloc) \
        !            71:                for (walkpointer = &allocwalk->symslots[0],\
        !            72:                        ubpointer = &allocwalk->symslots[SYMDALLOP], \
        !            73:                        ubpointer = ubpointer > ( (struct symtab *)alloctail) \
        !            74:                                 ? nextsym : ubpointer ;\
        !            75:                     walkpointer < ubpointer; \
        !            76:                     walkpointer++ )
        !            77: /*
        !            78:  *     The hash table is segmented, and dynamically extendable.
        !            79:  *     We have a linked list of hash table segments; within each
        !            80:  *     segment we use a quadratic rehash that touches no more than 1/2
        !            81:  *     of the buckets in the hash table when probing.
        !            82:  *     If the probe does not find the desired symbol, it moves to the
        !            83:  *     next segment, or allocates a new segment.
        !            84:  *
        !            85:  *     Hash table segments are kept on the linked list with the first
        !            86:  *     segment always first (that contains the reserved words) and
        !            87:  *     the last added segment immediately after the first segment
        !            88:  *     to hopefully gain something by locality of reference.
        !            89:  */
        !            90: struct hashdallop {
        !            91:        int     h_nused;
        !            92:        struct  hashdallop      *h_next;
        !            93:        struct  symtab          *h_htab[NHASH];
        !            94: };

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