FILE: HF0405.exe-Calling DOS & BIOS Interrupts w/FORTRAN & MASM

ID: Q71471

The information in this article applies to:

Microsoft FORTRAN for MS-DOS, versions 5.0, 5.1
Microsoft FORTRAN for OS/2, versions 5.0, 5.1

SUMMARY

To obtain the application note "Calling DOS and BIOS Interrupts with FORTRAN and MASM," call Microsoft Product Support Services. This application note contains preassembled versions of the MASM routines used to call DOS and BIOS interrupts.

MORE INFORMATION

The text of this application note is also available in the Microsoft Software Library.

The following file is available for download from the Microsoft Software Library:

 ~ HF0405.exe (size: 58988 bytes)

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   ARTICLE-ID: Q119591
   TITLE     : How to Obtain Microsoft Support Files from Online Services

The following is the text of the application note:

   Microsoft Product Support Services Application Note (Text File)
    HF0405: CALLING DOS AND BIOS INTERRUPTS WITH FORTRAN AND MASM

                                                   Revision Date: 8/91
                                                       1 Disk Included

This information applies to Microsoft FORTRAN versions 5.0 and 5.1.

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This application note illustrates how to access DOS interrupts without using the functions INTDOS and INTDOSX. DOS and BIOS interrupts can be called by specifying the interrupt number and the input register values within the main program. INTERRUPT and INTERRUPTX differ from the INTDOS and INTDOSX routines included with FORTRAN in that interrupts other than interrupt 21 can be called.

Included on the enclosed "Calling DOS and BIOS Interrupts with FORTRAN and MASM" disk are the following files. These files define the INTERRUPT and INTERRUPTX functions and provide two FORTRAN sample programs demonstrating how these functions are called.

File           Description
----           -----------

INTERRPT.ASM   The assembly source listing of the INTERRUPT and
               INTERRUPTX routines.

INTERRPT.INC   An include file for INTERRUPT and INTERRUPTX. This
               file contains the INTERFACE to the assembly routines
               and the register structures needed for INTERRUPT and
               INTERRUPTX.

INTERRPT.OBJ   The preassembled version of INTERRPT.ASM to be linked
               with programs calling INTERRUPT or INTERRUPTX.

INT.FOR        FORTRAN sample program that demonstrates how to use the
               INTERRUPT function call. INT.FOR uses INT 21, function
               2A hex to get the system date.

INTX.FOR       FORTRAN sample program using segment registers that
               demonstrates how to use the INTERRUPTX function call.
               INTXFOR uses INT 21, function 41 hex to delete a file.

INT.EXE        Executable version of INT.FOR example.

INTX.EXE       Executable version of INTX.FOR example.

The two assembly language routines included in INTERRPT.ASM are as follows:

1. INTERRUPT(INTNUM,INREGS,OUTREGS) invokes the interrupt specified by

   INTNUM using the values of INREGS and returns the result of the
   interrupt call in OUTREGS.

2. INTERRUPTX(INTNUM,INREGS,OUTREGS) invokes the system in the same

   manner as INTERRUPT but accepts segment register values.

To use the INTERRUPT and INTERRUPTX functions, the statement

   INCLUDE 'INTERRPT.INC'

must be located at the top of the source file where a call is made to the assembly language procedures. The two statement function definitions documented at the end of the INTERRPT.INC file must be uncommented and added to the source code of any FORTRAN program, function, or subroutine block where the assembly language procedures are called.

The statement functions documented at the end of INTERRPT.INC are shown below. These statement functions must appear before any executable statements. INTERRPT.OBJ must then be linked with the object file produced from compiling the main program.

   gethibyte (dataword) = dataword / 256
   getlobyte (dataword) = iand(dataword , 255)

Microsoft cannot guarantee that the information stated here regarding how to use INTERRUPT and INTERRUPTX will allow you to perform all MS- DOS system or BIOS calls correctly because this information has not been tested rigorously and is not considered a feature of the product.

Additional query words: Keywords : kbfile

Last Reviewed: December 10, 1998