To: DECUS "C" Users                       From: Jim Conroy X2346
     
                                               Dept: Automation Tools and
                                                     Technology - U2N27
     
                                               Date: 4/21/87
     
     cc:                                       Subj: Modifications to
                                                     DECUS "C" Compiler
     
     
     We  recently  had a need to segment a very large program into instruc-
     tion and data space.  We encountered some problems in the compiler and
     libraries  which  we were able to fix.  All programs that were changed
     are listed below and are included on this tape in the UICs listed  be-
     low.   Only programs that were modified are included with this submis-
     sion.  

     The  new "C" compiler, assembler and runtime libraries support I and D
     space.  It was built from the DECUS Fall '85 RSX SIG tape  (11-SP-90).
     Added  to  it  were the Australian submissions for split I and D space
     from the Spring '86 tape (11-SP-92).  The Australian  changes  can  be
     found in UICs [272,34], [272,35], and [272,37] on that tape.  Only the
     changes for I and D space were used.  The double-precision  arithmetic
     changes  were  not  included.   The merging of these two tapes has re-
     sulted in the use of these UICs:  

          1. [5,4] - compiler and assembler modules.
          2. [5,15] and [5,16] - C.OLB library routines.
          3. [5,24] - CX.OLB library routines.

     The resultant compiling system did not work well and we were forced to
     modify several programs.  Specific changes to each program are  listed
     in  the  edit  history  at the beginning of the program.  The programs
     changed were:  
     
          [5,4]CC200.MAC       [5,24]APCSV.MAC       [5,16]IOV.MAC
          [5,15]C5TA.MAC       [5,24]GMCR.MAC        [5,16]KBIN.MAC
          [5,15]ASCR50.MAC     [5,24]SETFNB.MAC      [5,16]KBINR.MAC
          [5,15]CALLER.MAC     [5,24]TLOG.MAC        [5,16]MEMDMP.MAC
          [5,15]CALLTR.MAC     [5,16]SUPORT.MAC      [5,16]PRMT.MAC
          [5,15]CTIME.MAC      [5,16]ABORT.MAC       [5,16]PROFIL.MAC
          [5,15]LOCALT.MAC     [5,16]ATOD.MAC        [5,16]RTIME.MAC
          [5,15]LTOA.MAC       [5,16]ATOF.MAC        [5,16]SCREEN.MAC
          [5,15]MALINK.MAC     [5,16]DOPRNT.MAC      [5,16]SETCC.MAC
          [5,15]MALLOC.MAC     [5,16]DOSCAN.MAC      [5,16]SLEEP.MAC
          [5,15]MAMCHK.MAC     [5,16]DTOA.MAC        [5,16]TIME.MAC
          [5,15]NARG.MAC       [5,16]ERROR.MAC       [5,16]TRAPS.MAC
          [5,15]PCSV.MAC       [5,16]EXIT.MAC        [5,16]PERROR.MAC
          [5,15]RAND.MAC       [5,16]FWILD.MAC       [5,16]IOPUT.MAC
          [5,15]RCTIME.MAC     [5,16]IOCSI.MAC       [5,16]PUTCHA.MAC
          [5,15]UNWIND.MAC     [5,16]IOFOPA.MAC      [5,16]FOPEN.MAC
          [5,15]ITOAX.MAC      [5,16]IOGET.MAC       [5,16]DTOAD.MAC
          [5,15]CTYPE.MAC      [5,16]IOGETC.MAC      [5,16]INIT.MAC
          [5,15]IOGETC.MAC     [5,16]IOFOPT.MAC      [5,16]IOFLSH.MAC
                               [5,16]DOUTAB.MAC      [5,16]UTIME.MAC
                                                                     Page 2



                               [5,16]ATOFD.MAC       [5,16]ATODD.MAC
     
     The changes to these programs can be summarized as follows:  

          1.  Change the compiler(CC200.MAC) to use a default psect type of
              d(data) on psects C$DATA and C$MWCN.  
          2.  Change library routines to use psect types of d on C$DATA and
              C$MWCN psects.  
          3.  Move  data from C$STRN to C$DATA since data is loaded at even
              addresses and string variables are concatenated at  the  next
              byte address.  This eliminates odd address traps.  
          4.  Fix MALLOC.  The Get Partition Parameters ESR in INIT.MAC was
              returning the total length of the task(I-space plus  D-space)
              rather than the length of D-space only.  This set up variable
              $$MEND incorrectly for MALLOC.  

     With  these  changes,  you  can  use instruction APRs by compiling and
     task-building in the normal way.  Use of instruction and data APRs  is
     turned  on by the /ID switch on the task-build.  The compiler has been
     used at three UNISYS  sites  for  about  four  months  with  no  major
     problems.  These changes come with the standard DECUS warranty.  





     James M. Conroy 
     Mail Station U2N27
     UNISYS Corporation
     P.O. Box 64525
     St. Paul, Mn. 55164-0525
     
     Phone: (612)456-2346