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001: /* This file is derived from the GAS 2.1.4 assembler control file.
002:    The GAS product is under the GNU General Public License, version 2 or later.
003:    As such, this file is also under that license.
004: 
005:    If the file format changes in the COFF object, this file should be
006:    subsequently updated to reflect the changes.
007: 
008:    The actual loader module only uses a few of these structures. The full
009:    set is documented here because I received the full set. If you wish
010:    more information about COFF, then O'Reilly has a very excellent book.
011: */
012: 
013: #define  E_SYMNMLEN  8   /* Number of characters in a symbol name         */
014: #define  E_FILNMLEN 14   /* Number of characters in a file name           */
015: #define  E_DIMNUM    4   /* Number of array dimensions in auxiliary entry */
016: 
017: /*
018:  * These defines are byte order independent. There is no alignment of fields
019:  * permitted in the structures. Therefore they are declared as characters
020:  * and the values loaded from the character positions. It also makes it
021:  * nice to have it "endian" independent.
022:  */
023:  
024: /* Load a short int from the following tables with little-endian formats */
025: #define COFF_SHORT_L(ps) ((short)(((unsigned short)((unsigned char)ps[1])<<8)|\
026:                                   ((unsigned short)((unsigned char)ps[0]))))
027: 
028: /* Load a long int from the following tables with little-endian formats */
029: #define COFF_LONG_L(ps) (((long)(((unsigned long)((unsigned char)ps[3])<<24) |\
030:                                  ((unsigned long)((unsigned char)ps[2])<<16) |\
031:                                  ((unsigned long)((unsigned char)ps[1])<<8)  |\
032:                                  ((unsigned long)((unsigned char)ps[0])))))
033:  
034: /* Load a short int from the following tables with big-endian formats */
035: #define COFF_SHORT_H(ps) ((short)(((unsigned short)((unsigned char)ps[0])<<8)|\
036:                                   ((unsigned short)((unsigned char)ps[1]))))
037: 
038: /* Load a long int from the following tables with big-endian formats */
039: #define COFF_LONG_H(ps) (((long)(((unsigned long)((unsigned char)ps[0])<<24) |\
040:                                  ((unsigned long)((unsigned char)ps[1])<<16) |\
041:                                  ((unsigned long)((unsigned char)ps[2])<<8)  |\
042:                                  ((unsigned long)((unsigned char)ps[3])))))
043: 
044: /* These may be overridden later by brain dead implementations which generate
045:    a big-endian header with little-endian data. In that case, generate a
046:    replacement macro which tests a flag and uses either of the two above
047:    as appropriate. */
048: 
049: #define COFF_LONG(v)   COFF_LONG_L(v)
050: #define COFF_SHORT(v)  COFF_SHORT_L(v)
051: 
052: /*** coff information for Intel 386/486.  */
053: 
054: /********************** FILE HEADER **********************/
055: 
056: struct COFF_filehdr {
057:         char f_magic[2];        /* magic number                 */
058:         char f_nscns[2];        /* number of sections           */
059:         char f_timdat[4];       /* time & date stamp            */
060:         char f_symptr[4];       /* file pointer to symtab       */
061:         char f_nsyms[4];        /* number of symtab entries     */
062:         char f_opthdr[2];       /* sizeof(optional hdr)         */
063:         char f_flags[2];        /* flags                        */
064: };
065: 
066: /*
067:  *   Bits for f_flags:
068:  *
069:  *      F_RELFLG        relocation info stripped from file
070:  *      F_EXEC          file is executable  (i.e. no unresolved external
071:  *                      references)
072:  *      F_LNNO          line numbers stripped from file
073:  *      F_LSYMS         local symbols stripped from file
074:  *      F_MINMAL        this is a minimal object file (".m") output of fextract
075:  *      F_UPDATE        this is a fully bound update file, output of ogen
076:  *      F_SWABD         this file has had its bytes swabbed (in names)
077:  *      F_AR16WR        this file has the byte ordering of an AR16WR
078:  *                      (e.g. 11/70) machine
079:  *      F_AR32WR        this file has the byte ordering of an AR32WR machine
080:  *                      (e.g. vax and iNTEL 386)
081:  *      F_AR32W         this file has the byte ordering of an AR32W machine
082:  *                      (e.g. 3b,maxi)
083:  *      F_PATCH         file contains "patch" list in optional header
084:  *      F_NODF          (minimal file only) no decision functions for
085:  *                      replaced functions
086:  */
087: 
088: #define  COFF_F_RELFLG          0000001
089: #define  COFF_F_EXEC            0000002
090: #define  COFF_F_LNNO            0000004
091: #define  COFF_F_LSYMS           0000010
092: #define  COFF_F_MINMAL          0000020
093: #define  COFF_F_UPDATE          0000040
094: #define  COFF_F_SWABD           0000100
095: #define  COFF_F_AR16WR          0000200
096: #define  COFF_F_AR32WR          0000400
097: #define  COFF_F_AR32W           0001000
098: #define  COFF_F_PATCH           0002000
099: #define  COFF_F_NODF            0002000
100: 
101: #define COFF_I386MAGIC          0x14c   /* Linux's system    */
102: 
103: #if 0   /* Perhaps, someday, these formats may be used.      */
104: #define COFF_I386PTXMAGIC       0x154
105: #define COFF_I386AIXMAGIC       0x175   /* IBM's AIX system  */
106: #define COFF_I386BADMAG(x) ((COFF_SHORT((x).f_magic) != COFF_I386MAGIC) \
107:                           && COFF_SHORT((x).f_magic) != COFF_I386PTXMAGIC \
108:                           && COFF_SHORT((x).f_magic) != COFF_I386AIXMAGIC)
109: #else
110: #define COFF_I386BADMAG(x) (COFF_SHORT((x).f_magic) != COFF_I386MAGIC)
111: #endif
112: 
113: #define COFF_FILHDR     struct COFF_filehdr
114: #define COFF_FILHSZ     sizeof(COFF_FILHDR)
115: 
116: /********************** AOUT "OPTIONAL HEADER" **********************/
117: 
118: /* Linux COFF must have this "optional" header. Standard COFF has no entry
119:    location for the "entry" point. They normally would start with the first
120:    location of the .text section. This is not a good idea for linux. So,
121:    the use of this "optional" header is not optional. It is required.
122: 
123:    Do not be tempted to assume that the size of the optional header is
124:    a constant and simply index the next byte by the size of this structure.
125:    Use the 'f_opthdr' field in the main coff header for the size of the
126:    structure actually written to the file!!
127: */
128: 
129: typedef struct 
130: {
131:   char  magic[2];               /* type of file                          */
132:   char  vstamp[2];              /* version stamp                         */
133:   char  tsize[4];               /* text size in bytes, padded to FW bdry */
134:   char  dsize[4];               /* initialized   data "   "              */
135:   char  bsize[4];               /* uninitialized data "   "              */
136:   char  entry[4];               /* entry pt.                             */
137:   char  text_start[4];          /* base of text used for this file       */
138:   char  data_start[4];          /* base of data used for this file       */
139: }
140: COFF_AOUTHDR;
141: 
142: #define COFF_AOUTSZ (sizeof(COFF_AOUTHDR))
143: 
144: #define COFF_STMAGIC    0401
145: #define COFF_OMAGIC     0404
146: #define COFF_JMAGIC     0407    /* dirty text and data image, can't share  */
147: #define COFF_DMAGIC     0410    /* dirty text segment, data aligned        */
148: #define COFF_ZMAGIC     0413    /* The proper magic number for executables  */
149: #define COFF_SHMAGIC    0443    /* shared library header                   */
150: 
151: /********************** SECTION HEADER **********************/
152: 
153: struct COFF_scnhdr {
154:   char          s_name[8];      /* section name                     */
155:   char          s_paddr[4];     /* physical address, aliased s_nlib */
156:   char          s_vaddr[4];     /* virtual address                  */
157:   char          s_size[4];      /* section size                     */
158:   char          s_scnptr[4];    /* file ptr to raw data for section */
159:   char          s_relptr[4];    /* file ptr to relocation           */
160:   char          s_lnnoptr[4];   /* file ptr to line numbers         */
161:   char          s_nreloc[2];    /* number of relocation entries     */
162:   char          s_nlnno[2];     /* number of line number entries    */
163:   char          s_flags[4];     /* flags                            */
164: };
165: 
166: #define COFF_SCNHDR     struct COFF_scnhdr
167: #define COFF_SCNHSZ     sizeof(COFF_SCNHDR)
168: 
169: /*
170:  * names of "special" sections
171:  */
172: 
173: #define COFF_TEXT       ".text"
174: #define COFF_DATA       ".data"
175: #define COFF_BSS        ".bss"
176: #define COFF_COMMENT    ".comment"
177: #define COFF_LIB        ".lib"
178: 
179: #define COFF_SECT_TEXT  0      /* Section for instruction code             */
180: #define COFF_SECT_DATA  1      /* Section for initialized globals          */
181: #define COFF_SECT_BSS   2      /* Section for un-initialized globals       */
182: #define COFF_SECT_REQD  3      /* Minimum number of sections for good file */
183: 
184: #define COFF_STYP_REG     0x00 /* regular segment                          */
185: #define COFF_STYP_DSECT   0x01 /* dummy segment                            */
186: #define COFF_STYP_NOLOAD  0x02 /* no-load segment                          */
187: #define COFF_STYP_GROUP   0x04 /* group segment                            */
188: #define COFF_STYP_PAD     0x08 /* .pad segment                             */
189: #define COFF_STYP_COPY    0x10 /* copy section                             */
190: #define COFF_STYP_TEXT    0x20 /* .text segment                            */
191: #define COFF_STYP_DATA    0x40 /* .data segment                            */
192: #define COFF_STYP_BSS     0x80 /* .bss segment                             */
193: #define COFF_STYP_INFO   0x200 /* .comment section                         */
194: #define COFF_STYP_OVER   0x400 /* overlay section                          */
195: #define COFF_STYP_LIB    0x800 /* library section                          */
196: 
197: /*
198:  * Shared libraries have the following section header in the data field for
199:  * each library.
200:  */
201: 
202: struct COFF_slib {
203:   char          sl_entsz[4];    /* Size of this entry               */
204:   char          sl_pathndx[4];  /* size of the header field         */
205: };
206: 
207: #define COFF_SLIBHD     struct COFF_slib
208: #define COFF_SLIBSZ     sizeof(COFF_SLIBHD)
209: 
210: /********************** LINE NUMBERS **********************/
211: 
212: /* 1 line number entry for every "breakpointable" source line in a section.
213:  * Line numbers are grouped on a per function basis; first entry in a function
214:  * grouping will have l_lnno = 0 and in place of physical address will be the
215:  * symbol table index of the function name.
216:  */
217: 
218: struct COFF_lineno {
219:   union {
220:     char l_symndx[4];   /* function name symbol index, iff l_lnno == 0*/
221:     char l_paddr[4];    /* (physical) address of line number    */
222:   } l_addr;
223:   char l_lnno[2];       /* line number          */
224: };
225: 
226: #define COFF_LINENO     struct COFF_lineno
227: #define COFF_LINESZ     6
228: 
229: /********************** SYMBOLS **********************/
230: 
231: #define COFF_E_SYMNMLEN  8      /* # characters in a short symbol name  */
232: #define COFF_E_FILNMLEN 14      /* # characters in a file name          */
233: #define COFF_E_DIMNUM    4      /* # array dimensions in auxiliary entry */
234: 
235: /*
236:  *  All symbols and sections have the following definition
237:  */
238: 
239: struct COFF_syment 
240: {
241:   union {
242:     char e_name[E_SYMNMLEN];    /* Symbol name (first 8 characters) */
243:     struct {
244:       char e_zeroes[4];         /* Leading zeros */
245:       char e_offset[4];         /* Offset if this is a header section */
246:     } e;
247:   } e;
248: 
249:   char e_value[4];              /* Value (address) of the segment */
250:   char e_scnum[2];              /* Section number */
251:   char e_type[2];               /* Type of section */
252:   char e_sclass[1];             /* Loader class */
253:   char e_numaux[1];             /* Number of auxiliary entries which follow */
254: };
255: 
256: #define COFF_N_BTMASK   (0xf)   /* Mask for important class bits */
257: #define COFF_N_TMASK    (0x30)  /* Mask for important type bits  */
258: #define COFF_N_BTSHFT   (4)     /* # bits to shift class field   */
259: #define COFF_N_TSHIFT   (2)     /* # bits to shift type field    */
260: 
261: /*
262:  *  Auxiliary entries because the main table is too limiting.
263:  */
264:   
265: union COFF_auxent {
266: 
267: /*
268:  *  Debugger information
269:  */
270: 
271:   struct {
272:     char x_tagndx[4];           /* str, un, or enum tag indx */
273:     union {
274:       struct {
275:         char  x_lnno[2];        /* declaration line number */
276:         char  x_size[2];        /* str/union/array size */
277:       } x_lnsz;
278:       char x_fsize[4];          /* size of function */
279:     } x_misc;
280: 
281:     union {
282:       struct {                  /* if ISFCN, tag, or .bb */
283:         char x_lnnoptr[4];      /* ptr to fcn line # */
284:         char x_endndx[4];       /* entry ndx past block end */
285:       } x_fcn;
286: 
287:       struct {                  /* if ISARY, up to 4 dimen. */
288:         char x_dimen[E_DIMNUM][2];
289:       } x_ary;
290:     } x_fcnary;
291: 
292:     char x_tvndx[2];    /* tv index */
293:   } x_sym;
294: 
295: /*
296:  *   Source file names (debugger information)
297:  */
298: 
299:   union {
300:     char x_fname[E_FILNMLEN];
301:     struct {
302:       char x_zeroes[4];
303:       char x_offset[4];
304:     } x_n;
305:   } x_file;
306: 
307: /*
308:  *   Section information
309:  */
310: 
311:   struct {
312:     char x_scnlen[4];   /* section length */
313:     char x_nreloc[2];   /* # relocation entries */
314:     char x_nlinno[2];   /* # line numbers */
315:   } x_scn;
316: 
317: /*
318:  *   Transfer vector (branch table)
319:  */
320:   
321:   struct {
322:     char x_tvfill[4];   /* tv fill value */
323:     char x_tvlen[2];    /* length of .tv */
324:     char x_tvran[2][2]; /* tv range */
325:   } x_tv;               /* info about .tv section (in auxent of symbol .tv)) */
326: };
327: 
328: #define COFF_SYMENT     struct COFF_syment
329: #define COFF_SYMESZ     18      
330: #define COFF_AUXENT     union COFF_auxent
331: #define COFF_AUXESZ     18
332: 
333: #define COFF_ETEXT      "etext"
334: 
335: /********************** RELOCATION DIRECTIVES **********************/
336: 
337: struct COFF_reloc {
338:   char r_vaddr[4];        /* Virtual address of item    */
339:   char r_symndx[4];       /* Symbol index in the symtab */
340:   char r_type[2];         /* Relocation type            */
341: };
342: 
343: #define COFF_RELOC struct COFF_reloc
344: #define COFF_RELSZ 10
345: 
346: #define COFF_DEF_DATA_SECTION_ALIGNMENT  4
347: #define COFF_DEF_BSS_SECTION_ALIGNMENT   4
348: #define COFF_DEF_TEXT_SECTION_ALIGNMENT  4
349: 
350: /* For new sections we haven't heard of before */
351: #define COFF_DEF_SECTION_ALIGNMENT       4
352: 

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