Dos Programmer'S Ref(Que)

 BBS: Inland Empire Archive
Date: 07-06-92 (20:13)             Number: 208
From: MATT HART                    Refer#: NONE
  To: RICHARD VANNOY                Recvd: NO  
Subj: Dos Programmer'S Ref(Que)      Conf: (2) Quik_Bas

 RV> I'm working on how to get assembler code into QB/PDS.
 RV> Comments and advice appreciated.

Here's a full assembler routine for QB that compiles under
MASM 5.x.  Also under MASM 6.0 by using C:\>ml /c memcopy
or by using the MASM pre-processor (which slows everything
down).

' In .BAS program:
     DEFINT A-Z
     CALL MemCopy (FSeg, FAdd, TSeg, TAdd, NumBytes)
' -------------

     Actually this routine can be improved quite easily.  I wrote it before I
started using the BYVAL keyword, which passes parameters by
value rather than by reference.  So the assembler commands:

    MOV  BX,FAdr           ;FAdr pointer
    MOV  SI,[BX]           ;Put into SI register

can be accomplished with:

    MOV  SI,FAdr

a single move and a much better time savings.  You cannot
pass a value BACK to the basic program when all parameters
are passed by value, but you can easily make all non-
changing parameters by value and the one you need to change
passed by reference:
     CALL Routine(BYVAL Param1, Ecode)
where Param1 is passed by value and Ecode by reference, so
it can receive something coming back.  Also, if NumBytes
was NOT even, you could do a single move byte and then use
MOVSW which moves two bytes at a time, much faster than
MOVSB.

After compiling, you have MEMCOPY.OBJ.  Just put the CALL into your program
wherever, and link with it:

     LINK Myprog + Memcopy,,,brt71enr;

This is VERY useful - copy blocks of memory up to 64K in
size from one area to another.  For greater than 32767, use
negative numbers with:
     NumBytes = CINT( 35&*1024& - 64&*1024& )
With this, you can do fixed length arrays (strings, TYPE,
numeric) deletes and inserts.  Copy multiple screens to
integer arrays.  All this stuff is practically
instantaneous.

;MEMCOPY.ASM
;All parameters must be integers
.Model Medium,BASIC
.Code
MemCopy PROC USES DS ES SI DI, FSeg:Ptr, FAdr:Ptr,
TSeg:Ptr, TAdr:Ptr, \
NumBytes:Ptr
    CLD                    ;Forward move

    MOV  BX,FAdr           ;FAdr pointer
    MOV  SI,[BX]           ;Put into SI register
    MOV  BX,TSeg           ;TSeg pointer
    MOV  ES,[BX]           ;Put into ES register
    MOV  BX,TAdr           ;TAdr pointer
    MOV  DI,[BX]           ;Put into DI register
    MOV  BX,NumBytes       ;NumBytes pointer
    MOV  CX,[BX]           ;Put into CX register
    MOV  BX,FSeg           ;FSeg pointer

    PUSH DS                ;Save DS to restore after move
    MOV  DS,[BX]           ;Put FSeg into DS register
    REP  Movsb             ;Move DS,SI to ES,DI
    POP  DS                ;Restore DS

    RET                    ;return to BASIC

MemCopy ENDP
END
~~
---
 * Origin: Midnight Micro!  V.32/REL  (918)451-3306 (1:170/600)