Path: utzoo!attcan!uunet!pilchuck!dataio!bright
From: bright@Data-IO.COM (Walter Bright)
Newsgroups: comp.sys.ibm.pc
Subject: Re: what can you tell me about DOS .OBJ files?
Keywords: assemblers and linkers and pigeons
Message-ID: <1570@dataio.Data-IO.COM>
Date: 15 Jun 88 17:22:08 GMT
References: <845@devon.UUCP>
Reply-To: bright@dataio.Data-IO.COM (Walter Bright)
Distribution: na
Organization: Data I/O Corporation; Redmond, WA
Lines: 18

In article <845@devon.UUCP> hermit@chessene.uucp writes:
>Can any of you kind knowledgable souls tell me where I might find
>information about the format of DOS .OBJ and .LIB files? I'm writing an
>80386 assembler, and it would be a bit easier if I didn't have to write a
>linker as well.

The DOS .OBJ file format is described in a document from Intel called
"Relocatable Object Module Format", you can call them at 800-538-3373.
Microsoft added a few extensions, they describe them in the OS/2 SDK
documentation. I've heard it's also described in the MS-DOS Encyclopedia,
but I haven't seen one.

Microsoft has tried to keep the .LIB format secret. It's not published
anywhere, but many people have figured it out.

The .OBJ format needs to be extended if 80386 code is to be assembled.
Check out how Phar Lap did this for their assembler, please avoid making
gratuitous new inventions unless absolutely necessary.