PILEXTL4 - HP-IL EXTensions for the HP-71, by John Baker
LEX file : PILEXTL4  -- VER$ is " PILEX:e"
Documentation : None on SWAP07. Source code is 80Kbytes. See source code for
ESCAPELX & early version of PILEXT & LENTER on CHHU06 / BBS files.
Description: This LEX files provides an extensive set of keywords that
facilitate handling HP-IL peripherals, to include Printers, Mass Storage
devices, EPROM burners, ect. This file combines most HPIL extensions written
by John R. Baker for the user community. This file included for use with HP-71
programs that generate HP-41 program barcode from files stored on mass
storage. See BAR71 / INDBAR71.
NOTE : All printer control codes / escape sequences are sent directly to the
PRINTER IS device. The control sequences are for the thinkjet printer, but
they will work with most HP printers...

The EPROM burner for which the BURN keyword is intended is the Mountain
Computer HP-IL EPROM burner. See the CHHU04 disk for the improved operating
system EPROM, file MC506V19. See also the EPROM2 program by Sam Chau, and
associated files BURNLEX, BURNLEXS, PILEXTS, PILEXTLX. Caution: Token
allocations have been changed. You must copy the files to RAM, TRANSFORM them
into text.... See CHHU04 EPROM files V15514A, V15514B, V15515, V15516, and
V15521, which are copies of the HP9114 operating system EPROMs. V15521 is
for B version drives, V15516 is the latest A version EPROM. Finally, see CHHU06
files VIDEO103 (Latest video interface operating system), MCGRAPHCJH (modified
video interface character set with pseudo graphic capability).

See also CHHU06 for other versions of PILEXTLX source code (LENTERS, PILEXTLX2).

BOLD ON/OFF             sets bold (double density) print mode
BURN <device>,<string>  Burn data stored in <string> on EPROM in <device>
        (sends each byte to burner with GET (Group Execute Trigger) frames.)
CKSUM (<file spec>)     See CHHU06 files AFS71 to TRYITOUT for application.
COMPRESS                sets compressed print mode
EIGHT ON/OFF            ON sets printer to 8 lines per inch, OFF ==> default.
EXPANDED                sets expanded print mode
EXPCMP                  sets expanded-compressed print mode
HALFFEED                advances thinkjet 1/2 distance of normal linefeed.
LENTER                  see below
MAXENTRY (<device>)     returns directory size of (mass storage) device
MAXSECT (<device>)      returns maximum sector of MEDIUM (formatted capacity)
NORMAL                  restores default print mode from COMPRESS,EXPANDED, ect
PERF ON/OFF             sets perforation skip printer mode
PPOLL [ (<loop #>) ]    Parallel Poll of selected loop. Must enable devices.
SETSOT [loop;] <type>,<arg>    See below
SST$ (<device>)         returns status of device as a string. Not limited to 4
                        bytes as SPOLL. returns null string if no response. 
TAPESTAT <device>       sets HP-71 to wait while (mass storage) device is busy.
UNDER ON/OFF            UNDERline thinjet printer mode
VERIFY <device>         executes DDL11 verify on 9114
VOLDATE$ (<device>)     returns date the medium in <device> was initialized.
VOLHEAD$                not implemented. Returns null string.
VOLUME$ (<device>)      returns volume label of mass storage medium in device
VOLUME <device> [,<label>]  changes volume label as specified on medium in dev.
WRAP ON/OFF             printer wrap-around mode
===============================================================================
VER$ : " PILEX:e"
===============================================================================
*      STITLE SETSOT keyword execution
**
** Purpose: set diamond sot response as a device
**   Notes: type... D=sdi, A=sai, S=sst
** This keyword would be used to emulate HP-IL peripherals with
** an HP-71. Related keywords are ON INTR, ENABLE INTR, READINTR,
** READDDC, REQUEST. Given enough memory, could emulate cassette drives,
** printer spooler (buffer), and more. Tricky but fun.
**
***********************************************************
*      STITLE LENTER execution
***********************************************************
**
** Purpose: enter bytes from device to string variable
**
** Syntax...
**        LENTER <device>;<S var>[,<T char>[,<strip list>]]
**
**       <device> is a standard HPIL device specifier
**
**       <S var> is a string variable or string array used
**              as the input list. This variable must exist
**              prior to entry or an error occurs.
**
**       <T char> is an optional terminating character. The
**              code always terminates on EOT or ENDs
**              see below for further description
**
**       <strip list> is a list of up to 2 characters to be
**              'stripped' from the end of an input string
**              typically used to strip trailing CRs & LFs
**
** System Flag -23 is used in the following manner by this
**       code. This use is not totally out of line...
**       there are two cases to be handled, Scalar & Array
**
**       When the input is to a scalar String variable then
**       EOT and END frames will always close entry & exit.
**       Likewise, if a <T char> is given, it also closes.
**       naturally, overflow closes
**       Flag -23 is ignored
**       chars are stripped by <strip list>
**
**       Input to an Array String is another story...
**       EOTs close entry and exit to NXTSTM or BSERR.
**       ENDs, <T char>s, or element overflows simply close
**       entry to that element and go to next element.
**       Naturally, when all elements are done, we exit!
**       Flag -23 works as follows...
**
**              Clear = ENDs, or <T char>s terminate all
**                     entry and exit to NXTSTM/BSERR
**                     this is like scalar operation
**
**              Set   = ENDs or <T char> only close element
**                     entry. EOT or all elements full is
**                     needed to exit to NXTSTM/BSERR.
**
** This should allow LENTER to handle most all entry
**       situations encountered. Notice that Flag -23 must
**       be set to allow array elements after the first to
**       be filled. This allows flexibility of input.
**
**       what may not be obvious is that if you want to
**       specify <strip char>s but have no <T char> active
**       then specify a null string for <T char>, i.e. ""
**       NOTE WELL..., CHR$(0) is NOT null...
**
** NOTE... I provide NO indication as to the last element
**       which was filled in an array. adding a variable to the
**       input list should be fairly easy
** Trace addr for arrays is zeroed because STMTxx conflicts
**      scalars trace because STMTxx use is finished then
**
************************************************************
*      STITLE CKSUM execution
***********************************************************
**
** Purpose: does a checksum on an arbitrary file
**
**   Notes: compute checksum starting at chain length field
**          works with any filetype however except for
**          executable files, results can be misleading
**               
**          also... for RAM based code which allocates data
**          storage within the file (BSS x), results can
**          be in error, caveat emptor!
**
***********************************************************
*      STITLE MAXENTRY execution
***********************************************************
**
** Purpose: returns the maximum number of directory entrys
**
**   Notes: converts only 2 low order bytes, ie max=2^16
**
***********************************************************
*      STITLE MAXSECT execution
***********************************************************
**
** Purpose: returns max single vector addr from sector 0
**
**   Notes: reads sector 0 for data per/M.Markov request
**          DDT7 returns 9114 drive mode info, not formatted capacity
**          of medium in drive. maximum sector count is 2^20 (HDFLT)
**
***********************************************************
*      STITLE VOLDATE$ execution
***********************************************************
**
** Purpose: return the time/date field of a media
**
**   Notes: 
**         15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
** start                S  s  N  n  H  h  D  d  M  m  Y  y
** date     3  Y  3  y  2  F  3  M  3  m  2  F  3  D  3  d
** time     3  H  3  h  3  A  3  N  3  n  3  A  3  S  3  s
**
***********************************************************
*      STITLE TAPESTAT execution
***********************************************************
**
** Purpose: wait during massmem call, errors if not busy
**
**   Notes: waits if bit 5 set, errors if 32>status>15
**          EXCEPT... if status=23d, then a new media has
**          been inserted. this is not a 'REAL' error so we
**          loop as with 'Busy'. errors are slightly
**          different for 82161 & 9114 so I defined 2 new
**          messages. the rest are from the HPIL ROM.
**
***********************************************************
*      STITLE PPOLL 
***********************************************************
**
** Purpose: parallel poll the pil
**