using the bootstrap loader

The syntax of the %SERIAL _ CHANNEL macro is as follows:
CONFIGURING THE FIRST STAGE
% SERIAL_ CHANNEL (serial_type, serial_base yort, serialyort_ delta,
counter_type, counter_base yort, counter yort_ delta,
baud_counter, count, flags)
where:
serial_type
serial_ base yort
serialyort _ delta
Bootstrap Loader
The serial controller device you are using. Valid values
are 8251A, 8274, and 82530.
The 16-bit port address of the base port used by the
serial channel. This port varies according to the type of
serial controller device and, if applicable, the channel
used on the device. To determine the port whose
address you should specify here, look at the left column
of the following list. Pick the item that corresponds to
the serial device on your CPU board and the channel
through which the CPU communicates with your
terminal. Then specify the port address of the
corresponding port listed in the right column. The
hardware reference manual for your CPU board lists the
port addresses for these serial devices.
Serial Channel
8251A
8274 Channel A
8274 Channel B
82530 Channel A
82530 Channel B
Base Port
Data Register Port
Channel A Data Register Port
Channel B Data Register Port
Channel A Command Register
Port
Channel B Command Register
Port
The number of bytes separating consecutive ports used
by the serial device.
The type of device containing the timer your CPU board
uses to generate a baud rate for the serial device defined
by this macro. Valid values are:
8253
80130
82530
8254
80186
NONE
Specifying NONE implies that the baud rate timer is
automatically initialized and the Bootstrap Loader does
not need to do this function.
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