#99 Support INPORT/INPORTB/OUTPORT/OUTPORTB on Window XP and higher

[David Costanzo]

OUTPORT and OUTPORTB are implemented using the X86 assembly instructions "out" and "outb". In operating systems which have a notion of usermode, these instructions are privileged and cannot be run, even by an administrator. Instead, the only way to execute them is to call them from kernel mode.

INPORT and INPORTB are implemented as simple MOV instructions on the given address. In operating systems which have a notion of usermode, these will result in an access violation if the given address is outside the address space of the process.

These instructions used to be used for low-level hardware manipulation. They worked in Windows 3.1 and Windows 9x, but would crash if run on any modern version of Windows. Because of this, I disabled these commands on Windows NT (Windows XP and later).

These are theoretically possible to implement, but doing so would require writing a kernel module (some called a "device driver"), loading it, and jumping from user-mode to kernel-mode to run the instruction. This is dangerous to play around with, as it can crash the entire operating system (blue screen of death) if misused or cause irreparable data loss.

At the moment, this is difficult to implement, as FMSLogo is not a native 64-bit application, the kernel module must match the native machine architecture, and I don't have access to software or hardware to test this. I also doubt that there are many FMSLogo users who want such a feature (I can only think of one). If implemented, it would mean shipping a kernel module with FMSLogo and the commands would only be accessible to administrators.

I have no plans to implement this feature, and certainly not until FMSLogo runs 64-bit natively, but if there is sufficient user interest as determined by posting on this ticket, I may consider implementing it after FMSLogo is 64-bit. Likewise, sufficient user interest might consider someone else to implement this.