Article ID: 44409
Article Last Modified on 11/21/2006
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
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 " *inArray* " and index:
FOR i = 1 TO Size%
inArray(i).StrElem = " *inArray* "
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 "inArray: "
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 "outArray: "
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
;***********************************************************
.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
; body
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
pop bp
ret
Masm ENDP
END
Additional query words: QuickBas BasicCom
Keywords: KB44409
