Microsoft KB Archive/44409

= Passing Dynamic Array of User-Defined TYPE from QB to MASM 5.x =

Article ID: 44409

Article Last Modified on 11/21/2006

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APPLIES TO


 * Microsoft QuickBasic 4.0
 * Microsoft QuickBASIC 4.0b
 * Microsoft QuickBasic 4.5 for MS-DOS
 * Microsoft BASIC Compiler 6.0
 * Microsoft BASIC Compiler 6.0b
 * Microsoft BASIC Professional Development System 7.0

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This article was previously published under Q44409



SUMMARY
This article contains a code example of passing a dynamic array of user-defined TYPEs to an assembly routine that copies the array to another array that is passed back to Basic.

The assembly routine requires Microsoft Macro Assembler Version 5.00 or later.



MORE INFORMATION
The arrays being passed can be larger than 64K when the Basic program is compiled with the BC /AH option (or if the QB.EXE or QBX.EXE editor is started with the /AH option).

Code Example
'Please note that it is necessary to pass the segment and 'the offset of a dynamic array being passed to assembly using 'VARSEG and VARPTR respectively.

'The following Basic program passes two arrays to a routine called MASM. 'The MASM routine copies the first array to the second array, 'passing it back to Basic through a parameter.

REM $DYNAMIC

TYPE testType StrElem AS STRING * 11 NumElem AS INTEGER       ' Size of integer is 2 END TYPE

' The underscore character for Basic PDS 7.00 must be taken out to ' use with BC.EXE. QBX.EXE will remove the underscores at load time ' and concatenate the line.

DECLARE SUB Masm (      BYVAL TypeLength AS INTEGER,_       BYVAL Length AS INTEGER,_       BYVAL SegAddr1 AS INTEGER,_       BYVAL Addr1 AS INTEGER,_       BYVAL SegAddr2 AS INTEGER,_       BYVAL Addr2 AS INTEGER) Size% = 20%    'Size of the array (# of elements) TypeSize% = 13% 'Size of TYPEs stored in array CLS DIM inArray(1 TO Size%) AS testType DIM outArray(1 TO Size%) AS testType

'Load inArray with a 11 character string &quot; *inArray* &quot; and index: FOR i = 1 TO Size% inArray(i).StrElem = &quot; *inArray* &quot; inArray(i).NumElem = i NEXT i

' The underscore character for Basic PDS 7.00 must be taken out to ' use with BC.EXE. QBX.EXE will remove the underscores at load time ' and concatenate the line.

' Masm will copy the contents of inArray to outArray: CALL Masm(TypeSize%,_         Size%,_          VARSEG(inArray(1)),_          VARPTR(inArray(1)),_          VARSEG(outArray(1)),_          VARPTR(outArray(1)))

' Print the inArray: PRINT PRINT PRINT &quot;inArray: &quot; FOR i = 1 TO Size% PRINT inArray(i).StrElem; inArray(i).NumElem NEXT i

' Print the outArray to see that the contents of inArray ' were copied to it:

PRINT PRINT &quot;outArray: &quot; FOR i = 1 TO Size% PRINT outArray(i).StrElem; outArray(i).NumElem NEXT i END

The Assembly Routine That Copies the Array --


 * The routine 'Masm' copies a dynamic TYPE array of any
 * length to another TYPE array.
 * Warning:
 * -- Arrays must be adequately and equally dimensioned.
 * Masm takes six parameters from the Basic routine:
 * 1 - Size of TYPEs in array to be copied (BX)
 * 2 - # of elements in Array
 * 3 - Segment of source array
 * 4 - Offset of first element of source array
 * 5 - Segment of destination array
 * 6 - Offset of first element of destination array
 * 6 - Offset of first element of destination array

.MODEL MEDIUM .CODE PUBLIC Masm

Masm   PROC push  bp     mov    bp, sp

mov   bx, [bp+16]   ; Size of TYPEs in array -> bx     mov    ax, [bp+14]   ; Elements in array -> ax     mul    bx     ; multiply ax by bx and put answer in ax     mov    cx,ax  ; Number of bytes in array -> cx

mov   es, [bp+12]   ; Segment of first array (inArray) mov   bx, [bp+10]   ; Offset of first element in first ; array mov   si,0 ; initialize first array index (inArray) again: mov   al,es:[bx] ; Load byte to copy to second array ; in al     push   bx         ; save bx     push   es         ; save es     mov    es, [bp+8] ; Segment of second array (outArray) mov   bx, [bp+6] ; Offset of second arrays first ; element add   bx,si ; Get correct offset into 2nd array from ; index mov   es:[bx],al ; Move the byte into the second array pop   es ; restore es     pop    bx ; restore bx     add    bx,1 ; point to next element in first array ; (inArray) add   si,1 ; increment second array (outArray) index loop   again ; Loop until cx is 0
 * body

pop   bp     ret Masm ENDP END

Additional query words: QuickBas BasicCom

Keywords: KB44409

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