Example of Passing Two-Dimensional Fixed-String Array to MASM (49400)

SUMMARY

The two programs shown below demonstrate how a Microsoft Basic program can pass a two-dimensional fixed-length string array to assembly language.

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 PDS versions 7.00 and 7.10 for MS-DOS and MS OS/2.

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:

BAS2MASM

Code Example

The following Basic program is BTWOFIX.BAS, which passes an uninitialized two-dimensional array of fixed-length strings to an assembly routine that initializes the array:

   DECLARE SUB TwoFix(BYVAL ASeg AS INTEGER, BYVAL AOff AS INTEGER)
   DIM FixArray(1 TO 2, 1 TO 3) AS STRING * 9
   CALL TwoFix(VARSEG(FixArray(1, 1)), VARPTR(FixArray(1, 1)))
   FOR row% = 1 TO 2
      FOR col% = 1 TO 3
         PRINT FixArray(row%, col%)
      NEXT
   NEXT
   END

The following program is ATWOFIX.ASM, which initializes a two-dimensional array of fixed-length strings passed from Basic:

; The following handy .MODEL MEDIUM,Basic directive is found in MASM
; 5.10 but not in earlier versions:
.MODEL MEDIUM, Basic
.DATA
        Fix11 DB 'String 11'     ; allocate string data
        Fix21 DB 'String 21'
        Fix12 DB 'String 12'
        Fix22 DB 'String 22'
        Fix13 DB 'String 13'
        Fix23 DB 'String 23'
.CODE
        PUBLIC TwoFix
TwoFix  PROC
        push bp
        mov bp, sp               ; set stack frame
        push es
        mov es, [bp+8]           ; segment of string array
        mov di, [bp+6]           ; offset of string array
        mov si, OFFSET Fix11     ; get offset to string data
        mov cx, 54               ; length of all string data
        rep movsb                ; copy string data to array
        pop es
        pop bp
        ret 4
TwoFix  ENDP
        END

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

     BC BTWOFIX.BAS;
     MASM ATWOFIX.ASM;
     LINK BTWOFIX ATWOFIX;

BTWOFIX.EXE produces the following output:

     String 11
     String 12
     String 13
     String 21
     String 22
     String 23