Calling DOS and BIOS Interrupts with FORTRAN and MASM

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

The text of this application note is also available in the Microsoft Software Library. Download HF0405.EXE, a self-extracting file, from the Microsoft Software Library (MSL) on the following services:

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MORE INFORMATION

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

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| Copyright 1991 Microsoft Corporation. All Rights Reserved.         |
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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.

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.

   INCLUDE 'INTERRPT.INC'

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)