Q64105: Example of Assembly Function Returning Long Integer to BASIC

Article: Q64105
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | H_MASM S_QUICKASM B_BasicCom SR# S900718-16 | mspl13_basic
Last Modified: 10-AUG-1990

The two programs below demonstrate how an assembly language function
can return a long integer to a Microsoft BASIC program.

This information about interlanguage calling applies to QuickBASIC
versions 4.00, 4.00b, and 4.50 for MS-DOS, to Microsoft BASIC Compiler
versions 6.00 and 6.00b for MS-DOS and MS OS/2, and to Microsoft BASIC
Professional Development System (PDS) versions 7.00 and 7.10 for
MS-DOS and MS OS/2.

For more information about passing other types of parameters between
BASIC and MASM, query in the Knowledge Base or the Software/Data
Library for the following word:

   BAS2MASM

Code Example
------------

The following BASIC program is IFUNC.BAS, which displays a long
integer returned from an assembly language function:

   DECLARE FUNCTION QPrint&

   FOR i% = 1 to 5
      PRINT QPrint&
   NEXT

The following program is AINT.ASM, which will return a long integer
parameter when called:

; The following handy .MODEL MEDIUM,BASIC directive is found in
; MASM 5.10 but not in earlier versions:
.MODEL MEDIUM, BASIC
.DATA
        longnum dd 12345

.CODE
        PUBLIC QPrint
QPrint  PROC
        mov ax, WORD PTR longnum        ; return value in ax and
        mov dx, WORD PTR longnum + 2    ;   dx registers
        ret
QPrint  ENDP
        END

To demonstrate these programs from an .EXE program, compile and link
as follows:

   BC IFUNC.BAS;
   MASM AINT.ASM;
   LINK IFUNC AINT;

IFUNC.EXE produces the following output:

   12345
   12345
   12345
   12345
   12345

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