BSD 4 release

[unix-history] / usr / src / cmd / as / as.h

diff --git a/usr/src/cmd/as/as.h b/usr/src/cmd/as/as.h
index 58d35b9..ca6cfbc 100644 (file)
--- a/usr/src/cmd/as/as.h
+++ b/usr/src/cmd/as/as.h
@@ -1,10 +1,61 @@
-/* Copyright (c) 1979 Regents of the University of California */
+/* Copyright (c) 1980 Regents of the University of California */
+/* "@(#)as.h 4.8 11/5/80" */
+#ifdef VMS
+# define       vax     1
+# define       VAX     1
+#endif VMS
+
+#include <sys/types.h>
+#ifdef UNIX
+
+#ifdef FLEXNAMES
+#  include <a.out.h>
+#  include <stab.h>
+#else not FLEXNAMES
+#  define ONLIST
+#  include "a.out.h"
+#  include <stab.h>
+#endif FLEXNAMES
+
+#endif UNIX 
+#ifdef VMS
+
+#ifdef UNIXDEVEL
+#  include <a.out.h>
+#else not UNIXDEVEL
+#  include <aout.h>
+#endif not UNIXDEVEL
+
+#endif VMS
+

 #define readonly
 #define readonly

-#define        NINST   300
-#define        NSYM    4000
-#define        NHASH   (NSYM+1)
-#define        NLOC    4               /* number of location ctrs */
-#define        NCPS    8               /* number of characters per symbol, fixed */
+#define        NINST           300
+
+#define        NEXP            20      /* max number of expr. terms per instruction */
+#define        NARG            6       /* max number of args per instruction */
+#define        NHASH           1103    /* hash table is dynamically extended */
+#define        TNAMESIZE       32      /* maximum length of temporary file names */
+#define        NLOC            4       /* number of location ctrs */
+
+#ifdef UNIX
+# ifndef       FLEXNAMES
+#      ifndef  NCPS
+#              define  NCPS    8       /* number of characters per symbol*/
+#      endif
+# else
+#      ifdef NCPS
+#              undef   NCPS
+#      endif
+#      define  NCPS    BUFSIZ  /* needed to allocate yytext */
+# endif
+# endif UNIX
+
+# ifdef VMS
+# ifdef NCPS
+#      undef   NCPS
+# endif NCPS
+#      define  NCPS    15
+# endif VMS

 
 /*
  * Symbol types
 
 /*
  * Symbol types


@@ -14,13 +65,7 @@
 #define        XTEXT   0x4
 #define        XDATA   0x6
 #define        XBSS    0x8
 #define        XTEXT   0x4
 #define        XDATA   0x6
 #define        XBSS    0x8

-#define        XDATAO  0xA
-#define        XBSSO   0xC
-#define        XTEXTO  0xE
-#define        XABSO   0x10
-#define        XUNDEFO 0x12

 
 

-#define        XTXRN   0xA     /* external symbol */

 #define        XXTRN   0x1
 #define        XTYPE   0x1E
 
 #define        XXTRN   0x1
 #define        XTYPE   0x1E
 


@@ -34,56 +79,80 @@
 /*
  * Actual argument syntax types
  */
 /*
  * Actual argument syntax types
  */

-#define AREG   1       /* %r */
-#define ABASE  2       /* (%r) */
-#define ADECR  3       /* -(%r) */
-#define AINCR  4       /* (%r)+ */
-#define ADISP  5       /* expr(%r) */
-#define AEXP   6       /* expr */
-#define AIMM   7       /* $ expr */
-#define ASTAR  8       /* * */
-#define AINDX  16      /* [%r] */
+#define        AREG    1       /* %r */
+#define        ABASE   2       /* (%r) */
+#define        ADECR   3       /* -(%r) */
+#define        AINCR   4       /* (%r)+ */
+#define        ADISP   5       /* expr(%r) */
+#define        AEXP    6       /* expr */
+#define        AIMM    7       /* $ expr */
+#define        ASTAR   8       /* * */
+#define        AINDX   16      /* [%r] */

 
 /*
  * Argument access types used to test validity of operands to operators
  */
 
 /*
  * Argument access types used to test validity of operands to operators
  */

-#define ACCA   (8<<3)  /* address only */
-#define ACCR   (1<<3)  /* read */
-#define ACCW   (2<<3)  /* write */
-#define ACCM   (3<<3)  /* modify */
-#define ACCB   (4<<3)  /* branch displacement */
-#define ACCI   (5<<3)  /* XFC code */
+#define        ACCR    (1<<3)                          /* read */
+#define        ACCW    (2<<3)                          /* write */
+#define        ACCB    (4<<3)                          /* branch displacement */
+#define        ACCA    (8<<3)                          /* address only */
+#define        ACCM    (ACCR | ACCW)                   /* modify */
+#define        ACCI    (ACCB | ACCR)                   /* XFC code */
+
+#define ACCESSMASK     (ACCA | ACCR | ACCW | ACCB)     /* the mask */
+
+/*
+ *     Argument data types
+ *     Also used to tell outrel what it is relocating
+ *     (possibly in combination with RELOC_PCREL and TYPNONE)
+ */
+#define        TYPB            0       /* byte */
+#define        TYPW            1       /* word */
+#define        TYPL            2       /* long */
+#define        TYPQ            3       /* quad */
+#define        TYPF            4       /* floating */
+#define        TYPD            5       /* double floating */
+#define        TYPNONE         6       /* when nothing */
+#define        RELOC_PCREL     8       /* implicit argument to outrel; ==> PCREL */
+
+#define        TYPMASK 7

 
 /*
 
 /*

- * Argument data types
+ *     reference types for loader

  */
  */

-#define TYPB   0       /* byte */
-#define TYPW   1       /* word */
-#define TYPL   2       /* long */
-#define TYPQ   3       /* quad */
-#define TYPF   4       /* floating */
-#define TYPD   5       /* double floating */
-
-#define TYPMASK 7
-
-/* reference types for loader */
-#define PCREL 1
-#define LEN1 2
-#define LEN2 4
-#define LEN4 6
-#define LEN8 8
-
-#define        TMPC    7       /* offset into the string /tmp/aaaXXX for creating tmp file names*/
+#define        PCREL   1
+#define        LEN1    2
+#define        LEN2    4
+#define        LEN4    6
+#define        LEN8    8
+
+extern int     reflen[];       /* {LEN*+PCREL} ==> number of bytes */
+extern int     lgreflen[];     /* {LEN*+PCREL} ==> lg number of bytes */
+extern int     len124[];       /* {1,2,4,8} ==> {LEN1, LEN2, LEN4, LEN8} */
+extern char    mod124[];       /* {1,2,4,8} ==> {bits to construct operands */
+extern int     type_124[];     /* {1,2,4,8} ==> {TYPB, TYPW, TYPL, TYPQ} */
+extern int     ty_NORELOC[];   /* {TYPB..TYPD} ==> {1 if relocation not OK */
+extern int     ty_LEN[];       /* {TYPB..TYPD} ==> {LEN1..LEN8} */
+extern int     ty_nbyte[];     /* {TYPB..TYPD} ==> {1,2,4,8} */
+extern int     ty_nlg[];       /* {TYPB..TYPD} ==> lg{1,2,4,8} */
+
+#define        TMPC    7       

 #define        HW      01
 #define        FW      03
 #define        DW      07
 
 #define        HW      01
 #define        FW      03
 #define        DW      07
 

-#include <pagsiz.h>
+#ifdef UNIX
+#  include <pagsiz.h>
+#endif UNIX
+
+#ifdef VMS
+#  define PAGRND       0x1FFL
+#endif VMS

 
 #define        round(x,y)      (((x)+(y)) & ~(y))
 
 #define        STABTYPS        0340
 
 #define        round(x,y)      (((x)+(y)) & ~(y))
 
 #define        STABTYPS        0340

-#define STABFLAG       0200
+#define        STABFLAG        0200

 
 /*
  *     Follows are the definitions for the symbol table tags, which are
 
 /*
  *     Follows are the definitions for the symbol table tags, which are


@@ -105,19 +174,19 @@
  *                     must get turned into their long form.
  */
 
  *                     must get turned into their long form.
  */
 

-#define TAGMASK                0xFF
+#define        TAGMASK         0xFF

 
 

-#      define  JXACTIVE        0xFF    /*jxxx instruction size unknown*/
-#      define  JXNOTYET        0xFE    /*jxxx instruction size known, but not yet expanded*/
+#      define  JXACTIVE        0xFF    /*jxxx size unknown*/
+#      define  JXNOTYET        0xFE    /*jxxx size known, but not yet expanded*/

 #      define  JXALIGN         0xFD    /*align jxxx entry*/
 #      define  JXALIGN         0xFD    /*align jxxx entry*/

-#      define  JXINACTIVE      0xFC    /*jxxx instruction size known and expanded*/
+#      define  JXINACTIVE      0xFC    /*jxxx size known and expanded*/

 
 

-#define JXQUESTIONABLE         0xFB
+#define        JXQUESTIONABLE          0xFB

 
 

-#      define  JXTUNNEL        0xFA    /*jxxx instruction that jumps to another*/
+#      define  JXTUNNEL        0xFA    /*jxxx that jumps to another*/

 #      define  OBSOLETE        0xF9    /*erroneously entered symbol*/
 
 #      define  OBSOLETE        0xF9    /*erroneously entered symbol*/
 

-#define        IGNOREBOUND     0xF8    /*symbols greater than this are ignored*/
+#define        IGNOREBOUND     0xF8            /*symbols greater than this are ignored*/

 #      define  STABFLOATING    0xF7
 #      define  LABELID         0xF6
 
 #      define  STABFLOATING    0xF7
 #      define  LABELID         0xF6
 


@@ -135,62 +204,112 @@
  *     Symbol table entries are used for both user defined symbols,
  *     and symbol slots generated to create the jxxx jump from
  *     slots.
  *     Symbol table entries are used for both user defined symbols,
  *     and symbol slots generated to create the jxxx jump from
  *     slots.

+ *     Caution: the instructions are stored in a shorter version
+ *     of the struct symtab, using all fields in sym_nm and
+ *     tag.  The fields used in sym_nm are carefully redeclared
+ *     in struct Instab and struct instab (see below).
+ *     If struct nlist gets changed, then Instab and instab may
+ *     have to be changed.

  */
 
  */
 

-#define symfirstfields char    *name;  unsigned char tag, type
-

 struct symtab{
 struct symtab{

-               symfirstfields;
-#ifdef vax
-               short   ___hole;
-#endif
-      /*save*/ char    ptype;          /*tag == NAME*/
-
-#define                jxbump  ptype           /*tag == JX..., how far to expand*/
-
-     /*save*/  char    other;          /*for stab info*/
-
-     /*save*/  short   desc;           /*tag == NAME*/
-
-#define                jxfear  desc            /*how far needs to be bumped*/
-
-     /*save*/  long    value;          /*address in the segment*/
-               char    jxoveralign;    /*if a JXXX, jumped over an align*/
-               short   index;          /*which segment*/
-               struct  symtab *dest;   /*if JXXX, where going to*/
+               struct  nlist   s_nm;
+               u_char  s_tag;          /* assembler tag */
+               u_char  s_ptype;        /* if tag == NAME */
+               u_char  s_jxoveralign;  /* if a JXXX, jumped over align */
+               short   s_index;        /* which segment */
+               struct  symtab *s_dest; /* if JXXX, where going to */

 #ifdef DJXXX
 #ifdef DJXXX

-               short   jxline;         /*source line of the jump from*/
+               short   s_jxline;       /* source line of the jump from */

 #endif
 };
 #endif
 };

-
-struct instab{
-       symfirstfields;
-
-#define                opcode type             /*use the same field as symtab.type*/
-
-       char    nargs;                  /*how many arguments*/
-       char    argtype[6];             /*argument type info*/
+/*
+ *     Redefinitions of the fields in symtab for
+ *     use when the symbol table entry marks a jxxx instruction.
+ */
+#define        s_jxbump        s_ptype         /* tag == JX..., how far to expand */
+#define        s_jxfear        s_desc          /* how far needs to be bumped */
+/*
+ *     Redefinitions of fields in the struct nlist for symbols so that
+ *     one saves typing, and so that they conform 
+ *     with the old naming conventions.
+ */
+#ifdef FLEXNAMES
+#define        s_name  s_nm.n_un.n_name        /* name pointer */
+#define        s_nmx   s_nm.n_un.n_strx        /* string table index */
+#else  not FLEXNAMES
+#define        s_name  s_nm.n_name
+#endif
+#define        s_type  s_nm.n_type             /* type of the symbol */
+#define        s_other s_nm.n_other            /* other information for sdb */
+#define        s_desc  s_nm.n_desc             /* type descriptor */
+#define        s_value s_nm.n_value            /* value of the symbol, or sdb delta */
+
+struct instab{
+       struct  nlist   s_nm;           /* instruction name, type (opcode) */
+       u_char  s_tag;                  
+       char    s_pad[3];               /* round to 20 bytes */

 };
 };

+/*
+ *     The fields nm.n_desc and nm.n_value total 6 bytes; this is
+ *     just enough for the 6 bytes describing the argument types.
+ *     We use a macro to define access to these 6 bytes, assuming that
+ *     they are allocated adjacently.
+ *     IF THE FORMAT OF STRUCT nlist CHANGES, THESE MAY HAVE TO BE CHANGED.
+ *
+ *     Instab is cleverly declared to look very much like the combination of
+ *     a struct symtab and a struct nlist.
+ */
+struct Instab{
+#ifdef FLEXNAMES
+       char    *I_name;
+#else not FLEXNAMES
+       char    I_name[NCPS];
+#endif
+       u_char  I_opcode;
+       char    I_nargs;
+       char    I_args[6];
+       u_char  I_s_tag;
+       char    I_pad[3];               /* round to 20 bytes */
+};
+/*
+ *     Redefinitions of fields in the struct nlist for instructions so that
+ *     one saves typing, and conforms to the old naming conventions
+ */
+#define        i_opcode        s_nm.n_type     /* use the same field as symtab.type */
+#define        i_nargs         s_nm.n_other    /* number of arguments */
+#define        fetcharg(ptr, n) ((struct Instab *)ptr)->I_args[n]

 
 struct arg {                           /*one argument to an instruction*/
 
 struct arg {                           /*one argument to an instruction*/

-       char    atype;
-       char    areg1;
-       char    areg2;
-       char    dispsize;               /*usually d124, unless have B^, etc*/
-       struct  exp *xp;
+       char    a_atype;
+       char    a_areg1;
+       char    a_areg2;
+       char    a_dispsize;             /*usually d124, unless have B^, etc*/
+       struct  exp *a_xp;

 };
 
 struct exp {
 };
 
 struct exp {

-       char    xtype;
-       char    xloc;
-       long    xvalue;
-       struct  symtab *xname;
-       union{
-               double  dvalue; 
-               struct {
-                       unsigned int doub_MSW, doub_LSW;
-               } dis_dvalue;
-       } doubval;
+       long    e_xvalue;               /* MUST be the first field (look at union Double) */
+       long    e_yvalue;               /* MUST be second field; least sig word of a double */
+       char    e_xtype;
+       char    e_xloc;
+       struct  symtab *e_xname;
+};
+
+#define doub_MSW e_xvalue
+#define doub_LSW e_yvalue
+
+union  Double {
+       struct{
+               long    doub_MSW;
+               long    doub_LSW;
+       } dis_dvalue;
+       double  dvalue;
+};
+
+struct Quad {
+       long    quad_low_long;
+       long    quad_high_long;

 };
 
 /*
 };
 
 /*


@@ -206,31 +325,19 @@ struct    exp {
  *             Is the floating point double word in xp a
  *             short literal floating point number?
  */
  *             Is the floating point double word in xp a
  *             short literal floating point number?
  */

-#define                slitflt(xp) \
-                       (    (xp->doubval.dis_dvalue.doub_LSW == 0) \
-                        && ((xp->doubval.dis_dvalue.doub_MSW & LITFLTMASK) \
-                          == xp->doubval.dis_dvalue.doub_MSW) )
-
-#define                extlitflt(xp) \
-                       xp->doubval.dis_dvalue.doub_MSW >> 4
-
+#define        slitflt(xp) \
+                       (    (xp->doub_LSW == 0) \
+                        &&  ( (xp->doub_MSW & LITFLTMASK) \
+                             == xp->doub_MSW) )

 /*
 /*

- *     Structure that appears at the head of a.out
+ *     If it is a slitflt, then extract the 6 interesting bits

  */
  */

-struct hdr {
-       long    magic;
-       long    tsize;
-       long    dsize;
-       long    bsize;
-       long    ssize;
-       long    entry;
-       long    trsize;
-       long    drsize;
-};
-
-       struct  arg     arglist[6];     /*building operands in instructions*/
-       struct  exp     explist[20];    /*building up a list of expressions*/
+#define                extlitflt(xp) \
+                       xp->doub_MSW >> 4

 
 

+       extern  struct  arg     arglist[NARG];  /*building operands in instructions*/
+       extern  struct  exp     explist[NEXP];  /*building up a list of expressions*/
+       extern  struct  exp     *xp;            /*current free expression*/

        /*
         *      Communication between the scanner and the jxxx handlers.
         *      lastnam:        the last name seen on the input
        /*
         *      Communication between the scanner and the jxxx handlers.
         *      lastnam:        the last name seen on the input


@@ -239,30 +346,35 @@ struct    hdr {
         */
        extern  struct  symtab  *lastnam;
        extern  struct  symtab  *lastjxxx;      
         */
        extern  struct  symtab  *lastnam;
        extern  struct  symtab  *lastjxxx;      

+
+#ifdef VMS
+       extern  char    *vms_obj_ptr;           /* object buffer pointer */
+       extern  char    sobuf[];                /* object buffer         */
+       extern  int     objfil;                 /* VMS object file descriptor */
+#endif VMS
+

        /*
        /*

-        *      For each of the named .text .data segments
-        *      (introduced by .text <expr>), we maintain
-        *      the current value of the dot, and the Files where
-        *      the information for each of the segments is salted
-        *      away.
-        *
-        *      Use of rulesfile and usefile is unclear
-        */
-       extern  struct  exp     usedot[NLOC+NLOC];
-       extern          FILE    *usefile[NLOC+NLOC];
-       extern          FILE    *rusefile[NLOC+NLOC];
-       /*
-        *      Strings used to construct the temporary files
-        *      for each of the named segments in pass 2.
+        *      Lgensym is used to make up funny names for local labels.
+        *      lgensym[i] is the current funny number to put after
+        *      references to if, lgensym[i]-1 is for ib.
+        *      genref[i] is set when the label is referenced before
+        *      it is defined (i.e. 2f) so that we can be sure these
+        *      labels are always defined to avoid weird diagnostics
+        *      from the loader later.

         */
         */

-       extern  char    *tmpn2;                 /* /tmp/aaaXXXX */
-       extern  char    *tmpn3;                 /* /tmp/aabXXX */
+       extern  int     lgensym[10];
+       extern  char    genref[10];

 
 

-       extern  struct  exp     *dotp;          /*the current dot location*/
+       extern  char    tmpn1[TNAMESIZE];       /* Interpass temporary */
+       extern  struct  exp     *dotp;          /* the current dot location */

        extern  int     loctr;
        extern  int     loctr;

-       extern  long    tsize;                  /* total text size */
-       extern  long    dsize;                  /* total data size */
-       extern  long    datbase;                /* base of the data segment */
+
+       extern  struct  exec    hdr;            /* a.out header */
+       extern  u_long  tsize;                  /* total text size */
+       extern  u_long  dsize;                  /* total data size */
+       extern  u_long  trsize;                 /* total text relocation size */
+       extern  u_long  drsize;                 /* total data relocation size */
+       extern  u_long  datbase;                /* base of the data segment */

        /*
         *      Bitoff and bitfield keep track of the packing into 
         *      bytes mandated by the expression syntax <expr> ':' <expr>
        /*
         *      Bitoff and bitfield keep track of the packing into 
         *      bytes mandated by the expression syntax <expr> ':' <expr>


@@ -280,19 +392,18 @@ struct    hdr {
         */
        extern  int     lineno;                 /*the line number*/
        extern  char    *dotsname;              /*the name of the as source*/
         */
        extern  int     lineno;                 /*the line number*/
        extern  char    *dotsname;              /*the name of the as source*/

-       /*extern FILE   stdin*;*/               /*the as source input*/

 
 

-       extern  FILE    *txtfil;                /* file for text*/

        extern  FILE    *tmpfil;                /* interpass communication*/
        extern  FILE    *tmpfil;                /* interpass communication*/

-       extern  FILE    *relfil;                /* holds relocation informtion*/

 
        extern  int     passno;                 /* 1 or 2 */
 
        extern  int     anyerrs;                /*errors assembling arguments*/
        extern  int     silent;                 /*don't mention the errors*/
        extern  int     savelabels;             /*save labels in a.out*/
 
        extern  int     passno;                 /* 1 or 2 */
 
        extern  int     anyerrs;                /*errors assembling arguments*/
        extern  int     silent;                 /*don't mention the errors*/
        extern  int     savelabels;             /*save labels in a.out*/

-               int     orgwarn;                /* questionable origin ? */
-               int     useVM;                  /*use virtual memory temp file*/
+       extern  int     orgwarn;                /* questionable origin ? */
+       extern  int     useVM;                  /*use virtual memory temp file*/
+       extern  int     jxxxJUMP;               /*use jmp instead of brw for jxxx */
+       extern  int     readonlydata;           /*initialized data into text space*/

 #ifdef DEBUG
        extern  int     debug;
        extern  int     toktrace;
 #ifdef DEBUG
        extern  int     debug;
        extern  int     toktrace;


@@ -300,33 +411,66 @@ struct    hdr {
        /*
         *      Information about the instructions
         */
        /*
         *      Information about the instructions
         */

-       struct  instab  *itab[NINST];           /*maps opcodes to instructions*/
-       extern  readonly struct instab instab[];
+       extern  struct  instab  *itab[NINST];   /*maps opcodes to instructions*/
+       extern  readonly struct Instab instab[];

 
 

-       int     curlen;                         /*current storage size*/
+       extern  int     curlen;                 /*current literal storage size*/
+       extern  int     d124;                   /*current pointer storage size*/

        
        struct  symtab  **lookup();             /*argument in yytext*/
        struct  symtab  *symalloc();
 
        
        struct  symtab  **lookup();             /*argument in yytext*/
        struct  symtab  *symalloc();
 

-#ifdef METRIC
-       int     outcounters;                    /*should we print them?*/
-       int     nhcollision;
-       int     nhashed;
-       int     nentered;
-       int     lgtmpfile;
-       int     jxxxiterate;
-       int     jxxxtunnel;                     /*how many tunnel jumps done*/
-       int     jxdeadlock;
-       int     nbadjxsegs;
-#endif
-
+#define outb(val) {dotp->e_xvalue++; if (passno==2) bputc((val), (txtfil));}

 
 

-#define outb(val) {dotp->xvalue++; if (passno==2) putc((val), txtfil);}
-
-#define outs(cp, lg) dotp->xvalue += (lg); if (passno == 2) fwrite((cp), 1, (lg), txtfil)
+#define outs(cp, lg) dotp->e_xvalue += (lg); if (passno == 2) bwrite((cp), (lg), (txtfil))

 
 /*
  *     Most of the time, the argument to flushfield is a power of two constant,
  *     the calculations involving it can be optimized to shifts.
  */
 #define flushfield(n) if (bitoff != 0)  Flushfield( ( (bitoff+n-1) /n ) * n)
 
 /*
  *     Most of the time, the argument to flushfield is a power of two constant,
  *     the calculations involving it can be optimized to shifts.
  */
 #define flushfield(n) if (bitoff != 0)  Flushfield( ( (bitoff+n-1) /n ) * n)

+
+/*
+ * The biobuf structure and associated routines are used to write
+ * into one file at several places concurrently.  Calling bopen
+ * with a biobuf structure sets it up to write ``biofd'' starting
+ * at the specified offset.  You can then use ``bwrite'' and/or ``bputc''
+ * to stuff characters in the stream, much like ``fwrite'' and ``fputc''.
+ * Calling bflush drains all the buffers and MUST be done before exit.
+ */
+struct biobuf {
+       short   b_nleft;                /* Number free spaces left in b_buf */
+/* Initialize to be less than BUFSIZ initially, to boundary align in file */
+       char    *b_ptr;                 /* Next place to stuff characters */
+       char    b_buf[BUFSIZ];          /* The buffer itself */
+       off_t   b_off;                  /* Current file offset */
+       struct  biobuf *b_link;         /* Link in chain for bflush() */
+};
+#define        bputc(c,b) ((b)->b_nleft ? (--(b)->b_nleft, *(b)->b_ptr++ = (c)) \
+                      : bflushc(b, c))
+#define BFILE  struct biobuf
+
+       extern  BFILE   *biobufs;       /* head of the block I/O buffer chain */
+       extern  int     biofd;          /* file descriptor for block I/O file */
+       extern  off_t   boffset;        /* physical position in logical file */
+
+       /*
+        *      For each of the named .text .data segments
+        *      (introduced by .text <expr>), we maintain
+        *      the current value of the dot, and the BFILE where
+        *      the information for each of the segments is placed
+        *      during the second pass.
+        */
+       extern  struct  exp     usedot[NLOC + NLOC];
+       extern          BFILE   *usefile[NLOC + NLOC];
+       extern          BFILE   *txtfil;/* file for text and data: into usefile */
+       /*
+        *      Relocation information for each segment is accumulated
+        *      seperately from the others.  Writing the relocation
+        *      information is logically viewed as writing to one
+        *      relocation saving file for  each segment; physically
+        *      we have a bunch of buffers allocated internally that
+        *      contain the relocation information.
+        */
+       struct  relbufdesc      *rusefile[NLOC + NLOC];
+       struct  relbufdesc      *relfil;