Q44135: BASIC Program That Passes a STATIC or DYNAMIC Array to MASM

Article: Q44135
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S890425-35 B_BasicCom H_MASM | mspl13_basic
Last Modified: 20-DEC-1989

Below is a QuickBASIC program that passes a STATIC or DYNAMIC array to
an assembly routine assembled with the Microsoft Macro Assembler
(MASM). The assembly routine assigns a 1 to each element in the array.
In the QuickBASIC program, the array can be initially defined as
DYNAMIC or STATIC, using REM $DYNAMIC or REM $STATIC.

This QuickBASIC program can be compiled with QuickBASIC Versions 4.00,
4.00b, and 4.50, Microsoft BASIC Compiler Versions 6.00 and 6.00b, and
with Microsoft BASIC PDS Version 7.00. The assembly program should be
assembled with MASM Version 5.10.

Code Examples
-------------

The following is the QuickBASIC program, MAIN.BAS, which calls the
assembly routine:

REM Program that calls an assembly routine that fills each
REM element with a 1. The segment, offset, and number of elements
REM in the array need to be passed BYVAL.
REM

DEFINT A-Z
DECLARE SUB MasmSub (BYVAL segment, BYVAL offset, BYVAL number)

'REM $DYNAMIC     'Can be either STATIC (the default) or DYNAMIC
DIM x%(1 TO 10)   'Remove comment to define array DYNAMICally

CLS
PRINT "Calling assembly routine to fill array elements..."
CALL MasmSub(VARSEG(x%(1)), VARPTR(x%(1)), 10)
PRINT "Values in array:"
FOR i = 1 TO 10
    PRINT x%(i);
NEXT
END

The following is the assembly program, MASMSUB.ASM, which assigns 1
to each array element:

;-------------------------------------------------------------------
; This assembly program loops through the array elements of an
; integer array that is passed to it via QuickBASIC and assigns a 1
; to each element. The segment, offset, and number of elements of
; the array need to be passed BYVAL from the QuickBASIC main module.
;
;-------------------------------------------------------------------

          .model medium
          .code
          public MasmSub
MasmSub   proc                 ;can use proc far here too
begin:    push bp              ;save registers for BASIC
          mov  bp,sp           ;get the stack pointer

          mov  es,[bp+10]      ;get segment of array
          mov  bx,[bp+8]       ;get offset of array

          mov  cx,[bp+6]       ;get length of array
          mov  al,1            ;fill array elements with 1's

next:     mov  es:[bx],al      ;put one in the array element
             add  bx,2   ;increment counter to next array element
                               ; -- add two bytes for integers, four bytes
                               ; -- for single precision and long integers,
                               ; -- and 8 bytes for double precision numbers
          loop next               ;loop to assign next array element
          pop  bp              ;restore bp for BASIC
          ret  6               ;restore stack
MasmSub   endp
          end

To compile and LINK each program, type the following MS-DOS commands:

   BC MAIN;
   MASM MASMSUB;
   LINK MAIN+MASMSUB;

To run the resulting executable, type the following (at the MS-DOS
prompt):

   MAIN

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