[Info-vax] Roadmap

[Dave Froble]

On 1/6/2019 7:57 PM, Simon Clubley wrote:
> On 2019-01-06, Dave Froble <davef at tsoft-inc.com> wrote:
>>
>> Pick only one of two, performance or accuracy ....
>>
>
> Does VMS Basic support fixed point ?
>
> (I've never used VMS Basic, so I don't know the answer).
>
> Simon.
>

Please define "fixed-point".

DECIMAL is supported.

There can be user defined data types.  Perhaps not with compiler 
support, but with support provided by library routines.

Ok, no laughing, or I'll feel hurt.  There is a large amount of this in 
our app storage.

This is from RSTS days.

100     !************************************************************
         !               Map Real Number into DI String
         !************************************************************
         !
         FUNCTION STRING DIIN( Z , Z% , ERROR% )
         !
         !  Z            - Real value
         !  Z%           - Scale factor
         !  ERROR%       - Completion status
         !
         !  DIIN ret val - DI mapped string
         !
         !************************************************************
         !
         OPTION SIZE=( INTEGER WORD , REAL DOUBLE )

200     ON ERROR GOTO 900                               !  Error trapping
         ERROR% = 0%                                     !  Clear error flag
         Z0 = Z * 10^Z% + SGN(Z)*.500001                 !  Scale to an 
integer
         Z1% = Z0 / 32768.                               !  High word value
         Z2% = Z0 - 32768.*Z1%                           !  Low word value
         DIIN = CVT%$(Z1%) + CVT%$(Z2%)                  !  Map into string
         GOTO 999                                        !  Exit
                                                         !
900     ERROR% = ERR                                    !  Set error flag
         DIIN = STRING$(4%,0%)                           !  Set no value
         RESUME 999                                      !  Exit
                                                         !
999     END FUNCTION

100     !************************************************************
         !              Un-map DI String to a real number
         !************************************************************
         !
         FUNCTION DOUBLE DIOUT( Z$ , Z% )
         !
         !  Z$           - DI mapped string
         !  Z%           - Scale factor
         !
         !  DIOUT        - Real value
         !
         !************************************************************
         !
         OPTION SIZE=( INTEGER WORD , REAL DOUBLE )

200     Z = 32768. * CVT$%(Z$) + CVT$%(MID(Z$,3%,2%))   !  Unmap string
         GOTO 300 UNLESS Z%                              !  Exit if not 
scaled
         Z = Z / 10.^Z%                                  !  Scale value
         CALL NROUND( Z , Z% )                           !  Round value
                                                         !
300     DIOUT = Z                                       !  Set Fn value
                                                         !
999     END FUNCTION

-- 
David Froble                       Tel: 724-529-0450
Dave Froble Enterprises, Inc.      E-Mail: davef at tsoft-inc.com
DFE Ultralights, Inc.
170 Grimplin Road
Vanderbilt, PA  15486