hey there again!

I've recently experimenting with 386+ hardware debugging features, and especially with Debug Extensions, available on Intel Pentium/AMD K5 and later, which allow (with some limitations) to implement simple I/O port trapping in pure real mode. As an example, I've made a TSR to redirect writes to port 0xC0 (used for Tandy Sound) to any other I/O port or to TNDLPT device on parallel port, while not requiring Virtual 8086 mode - this may have better compatibility than existing solutions like TNDY.COM or TNDLPT TSRs.

Download and source code: https://github.com/wbcbz7/TNDYBP

Please note that this method will not work on 386/486 (and possibly Cyrix CPUs), as these CPUs do not support hardware I/O port breakpoints, plus it works with real mode applications only - but as Tandy games are mostly written for the 8086/8088, this shouldn't be a much of issue. Although the hardware breakpoint feature can be used to circumvent Tandy checks, it is not implemented, so you still have to use patches executables with Tandy checks removed.

Any feedback/suggestions/bug fixes, as always, is welcome :)