c Xerox Corporation 1979Inter-Office MemorandumToDistributionDateJuly 25, 1979FromP. Deutsch, J. H. Morris, D. SwinehartLocationPalo AltoSubjectSYMS file formatOrganizationPARC/CSLXEROX File: SYMSFormat.pressThis memo summarizes the format of the SYMS files produced by BLDR. All numbers in thismemo are in octal.A SYMS file begins with a 20-word description vector. The "addresses" in this vector are wordaddresses relative to the beginning of the file.wordcontents01000 (a version number)1E, the length of the file (in words)2S, the address of the string area, currently always 203N, the address of the symbol table4R, the address of the BR file table5B, the address of the binary output file table6-170, currently unusedThe string area, starting at word S of the file, contains all the symbol names, BR file names, andbinary file names. Word S contains nS, the length of the string area (including the length worditself). Words S+1 to S+nS-1 contain BCPL strings. Their order is irrelevant, since all referencesto them are offsets relative to word S.The symbol table, starting at word N, contains one 4-word entry for each name defined in any ofthe BR files that was loaded. Word N contains nN, the number of names: the actual length of thesymbol table is therefore 4*nN+1. The format of the 4-word entry is as follows:wordcontents0the offset, relative to word S, of the symbol's name string1a type word whose bits are tttttxrbbbbbbbbb, where:t=1 for an ordinary static, 2 for a procedure, 3 for a label;x=0 if the name is external;r=1 if the name describes a relocatable (swappable) procedureb=the number of the BR file in which this name was defined (starting with 1)2the address of the static cell3the initial value loaded into the static cell%pqX]g7r{ bs]q -s7BqX ]s]q -s7Bq Ys]q-s 7BqStq P L&2 J G_X E0 B BWBBW ? =$  >:>)MATH  TIMESROMAN  TIMESROMAN TIMESROMANLOGOW j/  Osymsformat.bravo SwinehartSeptember 7, 1979 4:37 PM