Date   : Thu, 22 Aug 1985 20:35:25 PDT
From   : blc@JPL-VLSI.ARPA
Subject: dBaseII machine language interface

From:  VLSIDC::BLC          22-AUG-1985 20:33
To:    BLC
Subj:  dBase II machine query

Here is a sample dBaseII file which loads and calls a machine
language program.

* dBase II file to read diskcat files into dBase format
* 85.0212 BLC
*--!---!---!---!
* modified to load and use diread.z80
* 85.0403 BLC
* uses variable for catalog name, to allow several catalogs
* 85.0405 BLC
set delete on
set talk off
accept 'Date' to today
set date to &today
load diread
accept 'Catalog to Use' to diskcat
use &diskcat
do while T
text
options are:
   <D>isk ID order
   <E>xtention order
   <F>ull Printout
   <N>ame order
   <Q>ualified Printout
   <S>earch for File
   <U>pdate catalog
endtext
wait to command
store !(command) to command
if command='D'
   index on disk:id+name+ext to disk
endif
if command='E'
   index on ext+name+disk:id to ext
endif
if command='F'
   store 'T' to qual
   do printout
endif
if command='N'
   index on name+ext+disk:id to name
endif
if command='Q'
   accept 'Selection Function? ' to qual
   store !(qual) to qual
   do printout
endif
if command='S'
   accept 'Search for? ' to qual
   find &qual
   disp
endif
if command='U'
* directory read
* 85.0403 BLC
? 'Put new disk in B and press <return>'
wait
reset
copy stru to dir
use dir
store 'UNKNOWN' to d:id
store 'xxxxxxxxxxx' to entry
set call to 41984
call entry
set call to 41987
do while entry # 'NO DATA'
   if $(entry,9,3)="DID"
      store $(entry,1,8) to d:id
   else
      append blank
      replace name with $(entry,1,8)
      replace ext with $(entry,9,3)
      replace cat:date with date()
   endif
   call entry
enddo
   if d:id = 'UNKNOWN'
       ? 'No ID present'
       use &diskcat
   else
      replace all disk:id with d:id
      use &diskcat
      delete all for disk:id=d:id
      append from dir
   endif
enddo



The machine language program is created by:

; diread.z80
; directory reading program to call from dBase
; 85.0403 BLC
;---!---!---!---!
; buffer added
; 85.0403 BLC
    public one, two
    cseg
    .z80
bdos    equ 5
findf   equ 17  ;find first funct
findn   equ 18  ;  "   next   "
dmaf    equ 26
one:    jp first    ;a400h=41984
two:    jp next     :a403h=41987
fcb:    db 2        ; code for drive B
        db  "???????????"  ;for name and ext
        ds  24,0    ;rest of fcb all zeroed
psave:  dw 0        ;save the passed parameter
empty:  db  "NO DATA    "
buffer: ds  128     ;reserve a buffer
first:  ld  c,findf
        jp endup
next:   ld  c,findn
endup:  inc hl           ;skip the length byte of dBase string
        ld  (psave),hl   ;save the address
        push    bc       ;save the function
        ld  de,buffer    ;set dma to buffer
        ld  c,dmaf
        call    bdos
        pop bc           ; first or next back
        ld  de,fcb
        call bdos
        cp 255            ;flag for no match
        jp z,nomore
                         ;A has directory code
                         ;file name is at buffer+1+32*A
        ld  hl,buffer+1
        ld  de,32
again:  and a            ;to set z flag
        jp z,gotit
        dec a
        add hl,de
        jp again
gotit:  ld  de,(psave)   ;address of dBase string
        ld  bc,11        ;length of name+extention
        ldir             ;move it into the string
        ret
nomore: ld  hl,empty     ;no data message
        ld  de,(psave)
        ld  bc,11
        ldir
        ret
        end



After assembly, (with M80) the HEX file is created by linking 
such that,the laod address is A400H (41984, above the limit of 
memory used by dBase) as follows:

L80 /PA400,DIREAD,DIREAD/X/N/E


This is a pretty primative example, but it does exercise the
dBase machine language interface functions.

If anybody has any information regarding the defaults,
I would also be interested.


Bruce Conroy (BLC@JPL-VLSI.ARPA)