Example Passing Numerics from Basic to MASM by Near Reference (49383)

MORE INFORMATION

For more information about passing other types of parameters between Basic and MASM, search in the Microsoft Knowledge Base using the following word:

Code Example

The following Basic program is BNUMNEAR.BAS, which passes standard numeric types (by near reference) to assembly language routines:

 DECLARE SUB Numint(i%)
   DECLARE SUB Numlong(l&)
   DECLARE SUB Numsng(s!)
   DECLARE SUB Numdbl(d#)
   i% = 2                   ' Initialize values
   l& = 4
   s! = 3.4
   d# = 5.6
   CLS
   PRINT "         BEFORE","AFTER"
   PRINT "Integer: ";i%,,
   CALL Numint(i%)
   PRINT i%

   PRINT "Long   : ";HEX$(l&),,
   CALL Numlong(l&)
   PRINT HEX$(l&)

   PRINT "Single : ";s!,
   CALL Numsng(s!)
   PRINT s!

   PRINT USING "Double : ##.####            ";d#,
   CALL Numdbl(d#)
   PRINT USING "##.####"; d#

   END
				

The following assembler program is ANUMNEAR.ASM, which accepts standard numerics by near reference and alters their values:

; The following handy .MODEL MEDIUM,Basic directive is found in MASM
; 5.10 but not in earlier versions:
.MODEL MEDIUM, Basic
.CODE
        PUBLIC Numint, Numlong, Numsng, Numdbl
Numint  PROC
        push bp
        mov bp, sp        ; set stack frame
        mov bx, [bp+6]
        mov ax, [bx]   ; get integer
        shl ax, 1         ; multiply by 2
        mov [bx], ax   ; put new value back
        pop bp
        ret 2
Numint  ENDP

Numlong PROC
        push bp
        mov bp, sp        ; set stack frame
        mov bx, [bp+6]
        mov cx, [bx]   ; get long
        mov ax, [bx+2] ; switch high and low words
        mov [bx+2], cx ; put new value back
        mov [bx], ax
        pop bp
        ret 2
Numlong ENDP

Numsng  PROC
        push bp
        mov bp, sp        ; set stack frame
        mov bx, [bp+6]
        or byte ptr [bx+2],80h   ; Set sign bit
        pop bp
        ret 2
Numsng  ENDP

Numdbl  PROC
        push bp
        mov bp, sp         ; set stack frame
        mov bx, [bp+6]
        or byte ptr [bx+6],80h  ; Set sign bit
        pop bp
        ret 2
Numdbl  ENDP

        END
				

To demonstrate these programs from an .EXE program, compile and link as follows: BNUMNEAR.EXE produces the following output:

           BEFORE     AFTER
   Integer:  2          4
   Long   :  4          40000
   Single :  3.4       -3.4
   Double :  5.6000    -5.6000