Upload

Digital Research

MPM OPERATING SYSTEMS/MPM I/MPM I SOURCE/15/mpmugj-k.tex

@@ -0,0 +1,87 @@
+.MB +5
+.MT -3
+.LL 65
+.PN 148
+.HE MP/M User's Guide
+.FT   (All Information Herein is Proprietary to Digital Research.)
+.sp
+.ce
+APPENDIX J:  MP/M DDT Enhancements
+.pp
+The  following commands have been added to the MP/M  debugger
+to  provide  a  function  similar to CP/M's  SAVE  command  and  to
+simplify the task of patching and debugging PRL programs.
+.sp 2
+W:  WRITE DISK
+.pp
+The  purpose  of  the WRITE DISK command is  to  provide  the
+capability to write a patched program to disk.   A single parameter
+immediately  follows  the 'W' which is the number of  sectors  (128
+bytes/sector)  to be written.   This parameter is entered in  hexadecimal.
+.sp 2
+V:  VALUE
+.pp
+The purpose of the VALUE command is to facilitate use  of the
+WRITE DISK command by computing the parameter to follow the 'W'.  A
+single parameter immediately follows the 'V' which is the NEXT
+location following the last byte to be written to disk.
+.pp
+Normally a user would read in a file, edit it, and then write
+it back to disk.  The read command produces a value for NEXT.  This
+value  can be entered as a parameter following the 'V' command  and
+the number of sectors to be written out using the 'W' command  will
+be computed and displayed.
+.sp 2
+N:  NORMALIZE
+.pp
+The  purpose  of the NORMALIZE command is to relocate a  page
+relocatable  file which has been read into memory by the  debugger.
+To  debug  a  PRL  program the user would read it in  with  the 'R'
+command  and  then use  the 'N' command to relocate it  within  the
+memory segment the debugger is executing.
+.sp 2
+B:  BITMAP BIT SET/RESET
+.pp
+The purpose of the BITMAP BIT SET/RESET command is to  enable
+the user to update the bitmap of a page relocatable file.   To edit
+a  PRL  file the user would read the file in,  make changes to  the
+code,  and  then determine the bytes which needed relocation  (E.G.
+the  high  order  address bytes of  jump  instructions).   The  'B'
+command  would then be used to update the bit map.   There are  two
+parameters specified, the address to be modified (0100H is the base
+of the program segment),  followed by a zero or a one.   A value of
+one specifies bit setting.
+.AD
+.bp
+.sp 2
+.ce
+APPENDIX K:  Page Relocatable (PRL) File Specification
+.sp
+.pp
+Page  relocatable  files  are  stored  on  diskette  in  the
+following format:
+.li
+
+Address:    Contents:
+-------     --------
+
+0001-0002H  Program size
+
+0004-0005H  Minimum buffer requirements (additional memory)
+
+0006-00FFH  Currently unused, reserved for future allocation
+
+
+0100H + Program size  =  Start of bit map
+
+.ad
+.pp
+The  bit map is a string of bits identifying which bytes  are
+to be relocated.  There is one bit map byte per 8 bytes of program.
+The  most  significant  bit (7) of the first byte of  the  bit  map
+indicates  whether  or not the first byte of the program is  to  be
+relocated.  A bit which is on indicates that relocation is
+required.  The next bit,  bit(6),  of the first byte of the bit map
+corresponds to the second byte of the program.
+.br
+