User:Johnburger/Demo/Host

The development environment for a software engineer is a personal choice. I've used PCs most of my professional life, but I have used mainframes, minicomputers, SGI/HP/Sun Unix workstations and Macs too.

On the PCs I've used DOS, Linux and Windows, and I probably miss DOS the most. Hey, I'm an embedded engineer - I want to be close to the machine I'm working on! By using various virtualization programs I can still get the runtime environment I need, as described in Target Machine.

For this project, I did most of the development work under Windows 7 and VMware player.

Assembler

I wrote all the code in assembly. The assembler choice needed to be made up front, since different assemblers have different syntax or directives. I wanted you to be able to work with the code, so I also wanted to use a readily-available one. But since I've used Intel syntax for all my x86 life, I didn't want to make the mind-switch to Gnu's assembler - I'd be sure to make mistakes with the reversed opcodes!

So I've used NASM - and taken full advantage of two of my favourite features that it offers: local/hierarchical identifiers and macros.

The command line to assemble the source depends on how you want to use the output:

For CD:	nasm -o Demo.iso Demo.asm
For USB:	nasm -o Demo.usb Demo.asm
For Floppy:	nasm -o Demo.flp Demo.asm
For Hard Disk:	nasm -o Demo.bin Demo.asm

No, I'm not using some kind of fancy NASM macro to examine the output file name: this source code generates a single binary that can be used for any of the above media! You can tailor the code to invalidate any of the output types: for example, if you comment out the following line in Demo/Demo, you can still output a .iso file, it just won't work like one!

;%define         IMAGE.ISO       ; Write as bootable CD (ISO-9660 and El Torito)

IDE

I don't want to start a Holy War about the relative merits of different IDEs - I've used around a dozen in my decades of programming, and none are perfect. For this project I used a freeware editing environment called PSPad. Some of its advantages include:

• Simple text-based editing environment;
• Hex editor for binary files;
• Simple text-based project file (see below);
• Syntax highlighting;
• Invoke a build command, and capture and process the output for one-click jumps to errors;
• Above all: hierarchical project specification.

The following is the PSPad Project (.ppr) file. It's fairly straightforward in its layout: after a few project-specific settings, the file layout is there for all to see. You've probably guessed that there's a Wiki page for each of the files...

Demo/Demo.ppr

[Config]
Compilator.FileName=C:\NASM\NASM.exe
Compilator.PSPar=-l %Name%.lst %Name%%Ext%
Compilator.Log=%Name%.lst
Compilator.Run=CMD /c COPY %Name% %Name%.iso && COPY %Name% %Name%.flp
Compilator.SaveAll=1
Compilator.Capture=1
Compilator.ParsLog=%F:%L:* ; NASM
Compilator.HideOutput=1
Compilator.LogType=0
DefaultCPIndex=0
LogtoEnd=0
DontOpen=0
AbsolutePath=0
FileFormat=0
ProjectFilesOnly=0
[Project tree]
Demo
	Demo.asm
	Demo.inc
	Demo.lst
	Demo.map
	Demo
	+x86
		x86\x86.inc
		x86\EFlags.inc
		x86\Seg.inc
		x86\CR0.inc
		x86\Desc.inc
		x86\TSS.inc
		x86\IVT.inc
	+BIOS
		BIOS\BIOS.inc
		BIOS\A20.inc
		BIOS\RAMMap.inc
		BIOS\Key.inc
		BIOS\VGA.inc
		BIOS\Disk.inc
		BIOS\MBR.inc
		BIOS\MemMap.inc
	+Dev
		Dev\Dev.inc
		Dev\A20.inc
		Dev\PIC.inc
		Dev\Timer.inc
		Dev\Key.inc
		Dev\VGA.inc
	+Boot
		Boot\Boot.inc
		Boot\Entry.inc
		Boot\CPU.inc
		Boot\Load.inc
		Boot\IDT.inc
		Boot\RAM.inc
		Boot\A20.inc
		Boot\Key.inc
		Boot\VGA.inc
		Boot\PM.inc
	Data.inc
	+Ints
		Ints\Ints.inc
		Ints\IDT.inc
		Ints\Fault.inc
		Ints\Vectors.inc
		Ints\User.inc
		Ints\Single.inc
		+Debug
			Ints\Debug\Debug.inc
			Ints\Debug\Init.inc
			Ints\Debug\Key.inc
			Ints\Debug\Show.inc
			Ints\Debug\Regs.inc
		Ints\NoSeg.inc
		Ints\IRQs.inc
		Ints\Timer.inc
		Ints\Key.inc
		Ints\Util.inc
	+User
		User\User.inc
		User\LDT.inc
		User\Data.inc
		User\Code.inc
		User\Frame.inc
	+Exec
		Exec\Exec.inc
		Exec\Init.inc
		+Ints
			Exec\Ints\Ints.inc
			Exec\Ints\Debug.inc
			Exec\Ints\Trace.inc
			Exec\Ints\NoSeg.inc
			Exec\Ints\Double.inc
			Exec\Ints\BadStack.inc
			Exec\Ints\BadTSS.inc
			Exec\Ints\Fault.inc
		Exec\PICs.inc
		Exec\Timer.inc
		Exec\Key.inc
		+Start
			Exec\Start\Start.inc
			Exec\Start\LDT.inc
			Exec\Start\TSS.inc
		+Alloc
			Exec\Alloc\Alloc.inc
			Exec\Alloc\RAM.inc
			Exec\Alloc\DT.inc
			Exec\Alloc\IDT.inc
			Exec\Alloc\GDT.inc
			Exec\Alloc\LDT.inc
			Exec\Alloc\TSS.inc
		Exec\LDT.inc
		Exec\GDT.inc
	+Pad
		Pad\Sizes.inc
		Pad\HardDisk.inc
		+ISO
			Pad\ISO\ISO.inc
			Pad\ISO\Defn.inc
			Pad\ISO\Primary.inc
			Pad\ISO\Boot.inc
			Pad\ISO\Terminator.inc
			Pad\ISO\Catalog.inc
			Pad\ISO\PathTable.inc
			Pad\ISO\RootDir.inc
		Pad\Floppy.inc
[Open project files]
[Selected Project Files]
Main=Demo.asm