% Image file creation facility
% Jonathan Mark 1982

% This version has been modified to work under both Version 2 and
% Version 3 (I hope) of VMS.

% NOTE: line 168 of this file should possibly be modified to reflect
% the location of the prototype image header (HEAD0.EXE)

% Constant(s)

10 '#WRITES CONSTANT  % number of resident sections allowed in the image

% Variables

.D @ IF 1 .D+! THEN  % make the block start on a word boundary
80 'HEAD ARRAY  % 80 longwords = 1 block
80 'BLOCKBUF ARRAY
0 'ISD VARIABLE  % pointer to section descriptors
0 'PROTO_ISD VARIABLE  % prototype to supply flags, pointers
0 'FILE_POS VARIABLE  % keeps track of the block number
0 'WRT_FLAG VARIABLE  % false means set read-only access

0 'WRITE_COUNT VARIABLE  % count of scheduled write operations
0 'FIND_COUNT VARIABLE  % count of successfully found program regions
#WRITES 4 * 'SCHED_SOURCES ARRAY  % positive->from memory; negative->from file
#WRITES 2 * 'SCHED_COUNTS ARRAY  % contains the block counts

% Characteristic access words

'ISD.SIZE : ISD @ ;  % first word is size
'ISD.PAGCNT : ISD @ 2+ ;  % second word is page count
'ISD.VPN : ISD @ 4+ ;  % second longword (low 3 bytes) is virtual page number
'ISD.FLAGS : ISD @ 8 + ;  % third is flags
'ISD.VBN : ISD @ 0C + ;  % fourth is virtual block number

% Low-level words to change image section characteristics

'SET_NOWRT :  % ISD address, SET_NOWRT
  8 + DUP @ 08 NOT AND 02 NOT AND <-  % clear isd$m_wrt and isd$m_crf
  ;

'SET_NOCRF :  % ISD address, SET_NOCRF
  8 + DUP @ 02 NOT AND <-  % clear isd$m_crf
  ;

% IMAGE word to create a new image section (copying the header from
% a prototype in RKERNEL.EXE) containing all STOIC code and data
% presently compiled

% NOTE: the prototype RKERNEL.EXE must be linked without the debugger,
% but the STOIC version running IMAGE can be linked with or without it.

'FIX_DZRO :  % amount to reduce region by, FIX_DZRO
  10 ISD +!  % advance to the uninitialized ISD
  WRT_FLAG @ NOT IF ISD @ SET_NOWRT THEN  % if read-only, go set the flag
  DUP ISD @ 4+ +!  % add region count to BVPN
  ISD @ 2+ W@ SWAP - ISD @ 2+ W!
  ;

'FIX_COUNT :
  DUP ISD @ 2+ W@ - SWAP  % find the amount added
  DUP ISD @ 2+ W!  % save the new count in the ISD
  ;

'UPDATE_POINTERS :  % sets up protected region boundaries
  .D @ USER_DATA @ - USER_DATA @ W!  % set up data length
  DICT_PNTR @ 1FF + 1FF NOT AND USER_DICTIONARY !
  CODE_PNTR @ 1FF + 1FF NOT AND USER_CODE !
  ;

'SCHEDULE_WRITE :  % start address, length in blocks, SCHEDULE_WRITE
%  "Write scheduled: " MSG DDUP = = CR
  OVER HEAD NE_IF FILE_POS @ ISD.VBN ! THEN  % if not the header, set up ISD
  DUP FILE_POS +!  % calculate where the next one will be
  WRITE_COUNT @ 2* SCHED_COUNTS + W!  % save the length
  WRITE_COUNT @ 4 * SCHED_SOURCES + !  % save the start address
  WRITE_COUNT 1+!  % increment the count
  ;

'SCHEDULE_COPY :  % old block number, length in blocks, SCHEDULE_COPY
%  "Copy scheduled: " MSG DDUP = = CR
  FILE_POS @ ISD.VBN !  % tell it where it's going to start
  DUP FILE_POS +!  % calculate where the next one will be
  WRITE_COUNT @ 2* SCHED_COUNTS + W!  % save the length
  MINUS  % negate the block number to indicate what it is
  WRITE_COUNT @ 4 * SCHED_SOURCES + !  % save it
  WRITE_COUNT 1+!  % and increment the count
  ;

% This next word looks at an ISD in the prototype header and compares
% it with the region address and length that it is given.  Note that
% the data region is a special case.  The other two regions have not
% been moved in memory, so that the values to be written into the image
% are at the address given in the ISD.  The data ISD, however, starts
% at the data prototype address--but the region to be loaded into it
% is the actual, writable data region, not the prototype.	-JM

'CHECK_ISD :  % start address, section length in bytes, CHECK_ISD
  1- 200 / 1+  % get start address, length in blocks
  OVER 200 / ISD.VPN @ FFFFFF AND
  EQ_IF  % is this the one?
    OVER DATA_0 @ EQ_IF UNDER USER_DATA @ SWAP THEN  % data is a special case
    ISD @ SET_NOWRT  % it's one of ours, so make it read-only
    DDUP SCHEDULE_WRITE  % it's going to be written from memory
    FIX_COUNT DROP FIX_DZRO DROP  % update this section and the one after it
    FIND_COUNT 1+!
    -1  % signal that we found it
  ELSE
    2DROP 0  % drop data and signal failure if it's not it
  THEN
  ;

'DO_RESIDENT :  % schedule a write for a resident section
  DATA_0 @ .D @ USER_DATA @ - CHECK_ISD  % is it the data section?
  NOT IF
    DICT_0 @ DICT_PNTR @ OVER - CHECK_ISD  % is it the dictionary section?
    NOT IF
      CODE_0 @ CODE_PNTR @ OVER - CHECK_ISD  % is it the code section?
      NOT IF
        ISD.VBN @ ISD.PAGCNT W@ SCHEDULE_COPY  % if none of these, copy it
      THEN
    THEN
  THEN
  ;

'SCHEDULE_WRITES :  % look at all the ISDs; see which ones are resident
  0 WRITE_COUNT ! 1 FILE_POS !  % no writes so far
  HEAD 1 SCHEDULE_WRITE  % we're going to have to write out the image header
  HEAD DUP W@ + ISD !  % ISD points to the first Image Section Descriptor
  BEGIN  % loop through all ISDs
    ISD.SIZE W@ 10 EQ_IF  % is it a resident section?
      DO_RESIDENT  % if it is, go process it
    THEN
    ISD.SIZE W@ ISD +!  % move on to the next one
    ISD.SIZE W@ EQZ  % end the loop if there are no more
  END
  ;

'WRITE_BLOCK :  % address, block count, WRITE_BLOCK
  200 * 6 WRITE SYSERR  % out it goes, all at once
  ;

'COPY_BLOCK :  % starting block number, block count, COPY_BLOCK
  (  % we've got to do the blocks one by one
    DUP I + BLOCKBUF 200 RANDOGET SYSERR DROP  % read it
    BLOCKBUF 200 6 WRITE SYSERR    % write it
  ) DROP  % end and drop starting block number
  ;

'WRITE_IMAGE :  % actually performs all the scheduled writes
  WRITE_COUNT @ (
    I 4 * SCHED_SOURCES + @  % get the source address of block number
    GEZ_IF  % what is it? (if negative, its absolute val. is a block number)
      UNDROP I 2 * SCHED_COUNTS + W@ WRITE_BLOCK  % it's an address; write it
    ELSE
      UNDROP MINUS I 2 * SCHED_COUNTS + W@ COPY_BLOCK  % else copy it
    THEN
  )
  FIND_COUNT @ 3 NE_IF "Error: " MSG FIND_COUNT ? 
    " image sections found; there should have been 3" MSG
  THEN
  ;

'.IMAGE :  % file name, access flag (-1 or 0), .IMAGE
  WRT_FLAG !  % save the flag value
  FIND_COUNT 0<-  % reset the image section count
  UPDATE_POINTERS  % indicate how much code the new image should protect
  "SAO$KERNEL:HEAD0.EXE" 5 ROPEN  % open prototype image file
  1 HEAD 200 RANDOGET SYSERR DROP  % read in the image header
  SCHEDULE_WRITES  % go through the ISDs
%  DUP "output file name: " MSG MSG CR
  COUNT 6 .WOPEN_NCR SYSERR  % open the file to be written
  DATE D@  % save the current image's date
  SET_REVISION  % set a new date for the new image
  WRITE_IMAGE  % write out the new image file
  DATE D!  % and restore the status of the current image
  6 CLOSE  % close the output file
  5 CLOSE  % close the prototype image file
  ;

'IMAGE : 0 .IMAGE ;  % for normal image, cause read-only access
'IMAGE_WRT : -1 .IMAGE ;  % also allow for writable images

% Word to disable copy-on-referenceness in image files

'NOCREF :  % file name, NOCREF
  COUNT 5 .OPEN SYSERR  % open for random access
  1 HEAD 200 RANDOGET SYSERR DROP  % get the header
  HEAD DUP W@ +  % get first ISD address
  BEGIN
    DUP W@ NEZ
  IF
    DUP W@ 10 EQ_IF DUP SET_NOCRF THEN  % if resident, make not copy-on-ref
    DUP W@ +  % advance to the next one
  REPEAT DROP
  1 HEAD 200 RANDOPUT SYSERR  % write the header back out
  5 CLOSE  % close the file
  ;

% Words to display image section characteristics

'DISPLAY_ISD :  % address, DISPLAY_ISD, next ISD address
  DUP <#> TYPE ": " MSG
  "SIZE=" MSG DUP W@ <#> TYPE
  "; PAGCNT=" MSG DUP 2+ W@ <#> TYPE
  "; VPN=" MSG DUP 4+ @ <#> TYPE
  "; FLAGS=" MSG DUP 8 + @ 00FFFFFF AND <#> TYPE
  DUP W@ 10 EQ_IF "; VBN=" MSG DUP 0C + @ <#> TYPE THEN
  DUP W@ +  % advance
  ;

'SHOW :  % shows all ISD's in block starting at HEAD
  HEAD DUP W@ +  % initial pointer
  BEGIN
    DUP W@ NEZ
  IF
    DISPLAY_ISD CR
  REPEAT DROP
  ;

;F