SYSTEM RESET

         Reset the computer system.  General operation includes a test of
         of the CPU, ROM checksum, and initialization of hardware including:

            Memory system
            Timer/Counter (which is also used for RAM refresh)
            Interrupt Controller(s)
            DMA Controller(s)
            Keyboard Controller
            Video Controller & Video RAM
            Floppy Controller
            Hard Disk Controller (if present)

         Portions of the hardware may also have specific tests made to
         insure reliable operation.  Test failures may display error code
         on the screen if the video subsystem is operational, or generate
         beeps or LED blinks to signify the error.

         Note: A soft reset uses the warm_boot_flag to skip the memory
               tests. (i.e. from pressing Ctrl-Alt-Del).

         The system checks for installed ROMs by searching memory from
         C000h to the beginning of the BIOS, in 2K chunks.  ROM memory is
         identified if it starts with the word AA55h.  It is followed a one
         byte field length of the ROM (divided by 512).  If ROM is found,
         the BIOS will call the ROM at an offset of 3 from the beginning.
         This feature was not supported in the earliest PC machines.

         The last task turns control over to the bootstrap loader (assuming
         the floppy controller is operational)