> Any version of Delphi later than 1.0 (that is, any 32 bit version)
> doesn't allow you to access the hardware directly (version 1.0 had the
> Port() procedure) - so in order to do so you have to write a small piece
> of in-line assembler code - this is freely available on the net, and
> consists of a handful of op-codes. This then reads the port directly,
> and doesn't wait for Windows to give permission - which is why it's not
> included in 32 bit Delphi.

This is, unfortunately, not quite true. Although you can freely intersperse
direct I/O instructions in a Win32 executable on Win95/Win98/WinMe, those
instructions result in a trap the the 'virtual machine monitor' in Windows,
which virtualizes access to the hardware ports. This results in a
significant slowdown.

To get _real_ direct access to the ports you must use a device driver, even
in Win95/Win98/WinMe.

A device driver is required for any direct port access in WinNT/Win2000.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

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