Assembler Programming Tools

Conversion of an Assembler source program in the IBM PC / MS-DOS environment into a machine executable form requires an "Assembly" program to convert into an "object" file and then one or more "Linker" programs to convert "object" files into an "executable" program file. The standard "Assembly" program is MicroSoft's MASM; most IBM PC Assembler source programs are written to meet the MASM coding requirements. Most programs written for this standard also can be assembled with the near-compatible Turbo Assembler, TASM. For both of these Assemblers, the "object" files that they produce need to be passed through another program, Microsoft's LINK or Turbo's TLINK, to generate an .EXE-format executable program file, and then a further program, EXE2BIN, if it is desired to convert this into a .COM-style executable file.

There are several non-commercial/shareware/freeware Assembler programs and Linker programs also available. To be significantly useful, such programs need to be compatible with the "source" format expected by the MASM standard. One such Assembler is the freeware "Arrow Assembler"; the "Linker" associated with Arrow Assembler is called "VAL" which performs the functions of both LINK/TLINK and EXE2BIN.

Use of MASM in executable program generation

Sample Conversion Sequence for .EXE-style

          C:\masm>MASM
          Microsoft (R) Macro Assembler Version 5.00
          Copyright (C) Microsoft Corp 1981-1985, 1987.  All rights reserved.

          Source filename [.ASM]: GCD
          Object filename [GCD.OBJ]:
          Source listing  [NUL.LST]: GCD.LST
          Cross-reference [NUL.CRF]:

            50988 + 402788 Bytes symbol space free

                0 Warning Errors
                0 Severe  Errors


         C:\masm>LINK

         Microsoft (R) Personal Computer Linker  Version 2.40
         Copyright (C) Microsoft Corp 1983, 1984, 1985.  All rights reserved.

         Object Modules [.OBJ]: GCD.OBJ
         Run File [GCD.EXE]:
         List File [NUL.MAP]:
         Libraries [.LIB]:

         C:\masm>

- An additional step is required to convert from .EXE to .COM-style. After the LINK program has been run, the EXE2BIN program must be run to perform the .EXE to .COM conversion.
- Note that since a .COM-style program is composed of a single segment, there can be no separate stack segment. The use of a separate stack segment is desirable when dealing with .EXE programs which can support them; the LINK program therefore automatically produces an error message if it finds no separate stack segment.
  Warning: no stack segment
  For .COM-style programs this warning can safely be ignored.
- ```
          C:\masm>EXE2BIN GCD.EXE GCD.COM
          C:\masm>
```

Use of the Arrow Assembler and VAL in .EXE program execution

This freeware is locally available for FTP at ftp.algonquinc.on.ca/pub/infosystems/pincka/dat2343/arrowasm

          C:\arrowasm>ASM
          Arrowsoft Assembler
          Public Domain v2.00c (64K Model)
          Copyright (c) 1986, 1987 Arrowsoft Systems, Inc.

          Input filename  (.asm): GCD_EXE.ASM
          Object filename (GCD_EXE.obj):
          Listing filename(nul.lst): GCD_EXE.LST
          Cross-reference (nul.crf):
          Free memory=49418, Warnings=0, Errors=0

          Assembly Ended.

          C:\arrowasm>VAL
          VAL 8086 linker - Mar 27 1995
          OBJ file(s):  GCD_EXE.OBJ
          EXE file[c:\arrowasm\gcd_exe.exe]:
          LST file:
          LIB file(s):

          C:\arrowasm>

Use of the Arrow Assembler and VAL in .COM program execution

Within the Arrow-system, generation of a .COM file instead of a .EXE is only a matter of adding a switch to the VAL command

           C:\arrowasm>VAL    /CO
           VAL 8086 linker - Mar 27 1995
           OBJ file(s):  GCD.OBJ
           COM file[c:\arrowasm\gcd.com]:
           LST file:
           LIB file(s):

          C:\arrowasm>

Assembler Programming Tools

Use of MASM in executable program generation

Sample Conversion Sequence for .EXE-style

Sample MASM Conversion Sequence for .COM-style

Use of the Arrow Assembler and VAL in .EXE program execution

Use of the Arrow Assembler and VAL in .COM program execution