pmEasy

pmEasy* make using protected mode on Intel 286 Processor and higher processors easier. The first hurdle to writing an embedded, protected mode application is getting the processor ready to run the protected mode program. It is necessary to create descriptor tables, initialize processor registers, then switch into protected mode. Then it is necessary to develop trap and interrupt handlers and screen write functions to see what is happening. In these early stages developers often find themselves working in the dark and resorting to trial and error to diagnose problems.
pmEasy* provides proven code to enter protected mode, a well-written manual, helpful tips, and well-documented source code which explains exactly what has been done and why.
The second hurdle to protected mode development is debugging protected mode code. pmEasy provides an environment which is no more complex than necessary and which has good diagnostics and debug support. Among pmEasy's many features is a i386T Processor trap handler which writes informative error messages to the screen. pmEasy also supports the Periscope/32 and Soft-Scope remote debuggers which allow debugging the target via an RS-232 cable from a host computer.
pmEasy can be loaded and run three ways: via DOS, via disk boot sector and BIOS, and from ROM. Floppy, hard disk, and flash/RAM disk are supported. Loading via DOS is convenient in the initial stages of debugging.
Once pmEasy is loaded, it starts the application. If the application is to run from ROM, pmEasy transfers control to the application's entry point. Otherwise, it loads the application from disk and performs selector or offset fixups. (The file must be linked in Windows* .exe (NE) format or the NT Portable Executable (PE) format, which are produced by standard linkers). While the application is running, pmEasy provides services for: memory allocation and deallocation, local descriptor table management, and interrupt and trap management.