Does anyone know of a C++ compiler (free if possible) that can create OS-independent .COM executables for X86 (without a lot of, say, "hello I'm a windows-program"-type of code) This is because one day I want to create my own OS and/or compiler. I'd also like a modern 32-bit equivalent of the old Debug that came with dos/windows that displayed 16-bit machine code as ASM, so that I can see what the compiler creates...
> create OS-independent .COM executables for X86
No such animal exists.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
>> I'd also like a modern 32-bit equivalent of the old Debug that came with dos/windows
Until now I had never realized that debug.exe is 16-bit, lol!
edit: Is there a 32-bit version of debug.exe?
Last edited by BMJ; 01-11-2005 at 01:51 PM.
I'm sure does! They made windows using some generic C/C++, right folks?No such animal exists
Last edited by willkoh; 01-11-2005 at 03:24 PM.
> create OS-independent .COM
> I'm sure does! They made windows using some generic C/C++, right folks?
Right. That is because COM is a Microsoft executable format.
WARNING - I don’t have any hands-on experience with this stuff… So the following is hearsay, assumption, and speculation:
I think the Linux GCC compiler can do what you want. Because with Linux, you can boot a bootloader and then compile the OS… before you have a (complete) OS installed.
When you’re ready to learn to write an operating system, check-out Minix. Minix was created as a learning tool. The Minix source is free (not open source), but you have to pay for the book.This is because one day I want to create my own OS and/or compiler.
Of course, you can study the Linux source code. But, I wouldn’t attempt that unless you can find a really good study guide. (Linux 2.4 is 2.4 Million lines of code!!!)
You need a disassembler. A good Compiler/IDE with a debugger should include a disassembler. I’m pretty sure that the MS Visual C++ debugger has one....that displayed 16-bit machine code as ASM,
> I'm sure does! They made windows using some generic C/C++, right folks?
Sure, and what about Linux, Solaris, NetBSD, OpenBSD, FreeBSD and a host of other operating systems which you've never heard of.
None of those are going to think much about 16-bit COM files.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
For a command line tool, try ntsd. WinDbg is the GUI version.I'd also like a modern 32-bit equivalent of the old Debug that came with dos/windows that displayed 16-bit machine code as ASM
Well to those who say .COM's are either always 16-bit (not true) or a microsoft concept (not true either) I just want to let them know. I've read about them in old assembler books. The exe:s are relocatable so they can be put and operate in any area memory were space is available, that's the main/defining difference... A .COM is simple usually not very OS oriented (because it's either the startup-file of an OS or an old and therefore simple tool for that OS) and would be the thing to use for learning machine code or startup of an OS (when you know free memory starts at 0)
Still, you're going to be SOL as soon as your program wants to say
- display anything
- read input
- read a file.
Because all those services are very specific to each and every OS.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
Well, there are the BIOS routines for doing such things (it has text-printing and I think a standard screen mode for that). It has not file reading (since it's specific to the OS and FileSystem), but sector reading. Then I can learn how to communicate with the graphics card for doing manual (more advanced) graphics...
There has to be some generic C/C++ compiler!
Sure because every BIOS is the same too
-err no.
Try learning something before speaking next time. If you really want to get into OS design then learn assembly. This will serve as the base for your OS and it is the only way to start to build one.
If you want to get into compiler design check out the red dragon book, do a search on this board for other books, or *gasp* try google.
You are correct as in the idea of executable programs is not microsoft original, however the implementation of an executable IS OS dependant and thus there is no "generic" compiler that you speak of since the implementation is different for each OS.
i don't think most standard compilers support programmers with more than 4 red boxes - Misplaced
It is my sacred duity to stand in the path of the flood of ignorance and blatant stupidity... - quzah
Such pointless tricks ceased to be interesting or useful when we came down from the trees and started using higher level languages. - Salem
This is all correct, but it requires assembly. The bios interrupt is 0x10, and you use the registers AH, AL, BH, and BL in order to set the text and attributes. No C or C++ compiler (that I know of anyways) is going to help you here.Well, there are the BIOS routines for doing such things (it has text-printing and I think a standard screen mode for that). It has not file reading (since it's specific to the OS and FileSystem), but sector reading. Then I can learn how to communicate with the graphics card for doing manual (more advanced) graphics...
...but they did use C rather than assembler to make windows!
To make MOST of of windows. Bootstrap loaders have to be written in assembly. And the code used to make windows isn't compiled on any magic compiler. It's just that you won't be able to call any functions that are normally defined by the OS. In other words, you'll have basic C syntax, but you'll have to code all your routines for input, etc... in assembly.
