imp@Solbourne.COM (Warner Losh) (06/06/90)
Has anybody done any really strange interrupt hacking on a PC or PC-oid? I just got done hacking something together for my Rainbow to let TCC run on it unmodified. The problem: INT 18 is unused on a PC. It is the one ROM bios routine on the Rainbow. the rainbow also has a MFU watchdog timer that causes a system reset if the interrupts are off more than 100ms (or so). When TCC establishes its interrupt routine, it causes the interrupts to be turned off (indirectly), and the system resets. So, what I did was to trap the Get Vector and Set Vector functions of DOS. I also have my own INT 18 handler that calls ROM when the call is from "Low memory" or the ROMs, but calls the routine that has been set in the Set Vector "call" to dos. It works great. Fun stuff I tell you. Now when DOS calls the ROMs to do its stuff, they do their stuff. When TCC calls its INT 18 handlers, TCC's INT 18 handler gets called and everybody is happy. Aren't TSR's wonderful? Anybody done anything similar? Warner Losh imp@Solbourne.COM