

                 BEWARE FILE FOR APL-BASIC-20 V2(435)


                            September 1979


COPYRIGHT (C) 1976,1979 BY
DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASS.


THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND  COPIED
ONLY  IN  ACCORDANCE  WITH  THE  TERMS  OF  SUCH  LICENSE AND WITH THE
INCLUSION OF THE ABOVE COPYRIGHT NOTICE.  THIS SOFTWARE OR  ANY  OTHER
COPIES  THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY
OTHER PERSON.  NO TITLE TO AND OWNERSHIP OF  THE  SOFTWARE  IS  HEREBY
TRANSFERRED.

THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE  WITHOUT  NOTICE
AND  SHOULD  NOT  BE  CONSTRUED  AS  A COMMITMENT BY DIGITAL EQUIPMENT
CORPORATION.

DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR  RELIABILITY  OF  ITS
SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.
APL.BWR V2(435)                                                 Page 2


APL.BWR -- BEWARE File for V2(435)
September 1979


The following patches must  be  made  to  field-image  PA1050  version
3A(307)   to  allow  APL  version  2  to  function  correctly  on  the
DECSYSTEM-20:

     1.  To make a linefeed echo as a linefeed instead of  a  carriage
         return, linefeed pair, patch the CCOC word:

         FCOC2/ 52532,,565125 should be 52532,,525125

     2.  To insure that control characters echo as  "up-arrow  letter"
         on  input  but are sent to the terminal unmolested on output,
         be sure that the following instructions are present:

         TTYST0+5/ TRZA 2,300
                   TRO 2,300

     3.  TCO 4.2239 must be installed to allow  /BS/DUMP  I/O  to  mag
         tape:

         Problem:  The MTCHR.  UUO returns 0 in the left half  of  the
         AC instead of the length of the record last read.

         Diagnosis:  PA1050 was never taught to do this.

         Solution:  Get the length of the last  record  in  bytes  and
         divide  by  the  bytes  per word based on the data mode since
         MTCHR.  expects the record length in words.

         Edit 326 puts the following code in from MTCHR3-2 to MTCHR1:

         PUSH P,C           ;(326) SAVE DENSITY
         GDSTS              ;(326) GET DEVICE STATUS
MTCHR4:                     ;(326)
         HLRZS C            ;(326) RIGHT-JUSTIFY BYTE COUNT
         PUSH P,C           ;(326) SAVE BYTE COUNT
         MOVEI B,.MORDM     ;(326) READ TAPE DATA MODE (JFN ALREADY
SET)
         MTOPR              ;(326) SHOULD NEVER RETURN 0 == SYSTEM
DEFAULT
           ERJMP RETZER     ;(326) SHOULDN'T HAPPEN
         HLRZ B,TPRDMT(C)   ;(326) GET BYTES PER WORD
         POP P,C            ;(326) GET BYTE COUNT
         IDIV C,B           ;(326) CONVERT BYTES TO WORDS
         SKIPE D            ;(326) ROUND UP TO NEXT HIGHER WORD
           AOS C            ;(326) IF NEEDED
         POP P,A            ;(326) GET DENSITY
         HRL A,C            ;(326) PUT IN WORD COUNT
         JRST STOTC1        ;RETURN ANSWER
MTCHR3:  GDSTS              ;(326) GET DEVICE CHARS (JFN ALREADY SET)
         LDB B,[POINT 2,B,28] ;(326) GET DENSITY
APL.BWR V2(435)                                                 Page 3


         SKIPN B            ;(326) IS IT 0 ?
           MOVEI B,3        ;(326) YES, MAKE IT 3
         PUSH P,B           ;(326) SAVE DENSITY
         JRST MTCHR4        ;(326) C ALREADY SET BY GDSTS
MTCHR1:  MOVEI D,17         ;SEARCH FOT THIS DEV INITED

To install a patch in PA1050, do the following:

         @GET PAT   ! get PAT.EXE v3A(307)
         @DDT
         DEBUG$G    ! $ is an ESCape
         PAT$:
         FCOC2/  52532,,565125     52532,,525125
         TTYST0+5/  TRZA 2,300   ! hit linefeed
                    TRO 2,300
         MAKEPF$G
         output file: $

         <a new version of PA1050.EXE is put in your connected
         directory>


[End of APL.BWR]
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