Q49396: Example of Passing Variable-Length String from BASIC to MASM
Article: Q49396 Product(s): See article Version(s): 4.00 4.00b 4.50 Operating System(s): MS-DOS Keyword(s): ENDUSER | B_BasicCom H_MASM S_QuickASM | mspl13_basic Last Modified: 10-AUG-1990 The two programs below demonstrate how a Microsoft BASIC program passes a variable-length string to assembly language by near reference. 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, search in the Software/Data Library for the following word: BAS2MASM Code Example ------------ The following BASIC program is BSTR.BAS, which passes the offset of a variable-length string to assembly language: DECLARE SUB RString(BYVAL soff AS INTEGER) A$ = "This is the string" + "$" ' "$" terminates string for INT call CALL RString(SADD(A$)) END The following program is ASTR.ASM, which gets the address of a variable-length string and prints the string out: .MODEL MEDIUM .CODE PUBLIC RString RString PROC push bp mov bp, sp ; set stack frame mov dx, [bp+6] ; get offset to string mov ah, 9 ; DOS interrupt to print string int 21h pop bp ret 2 RString ENDP END To demonstrate these programs from an .EXE program, compile and link as follows: BC BSTR.BAS; MASM ASTR.ASM; LINK BSTR ASTR; BSTR.EXE produces the following output: This is the string
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