using the bootstrap loader

", ", """""", " " , " " "", " """"", " ",
Constants and Data
", ", """" "" , " " , " " """ """", ", , " "
data bsmsc segment ;Static Data
wakeup_newdrvl dw lOOH ;MSC wakeup address
device newdrvl db 0
WRITING A CUSTOM FIRST-STAGE DRIVER
drtab newdrvl dw 256 ; number of cylinders
db 2 ; number of fixed heads
db 0 ; number of removable heads
db 9 ; number of sectors
db 1024 ; device granularity
db 5 ; number of alternate cylinders
Figure 5-1. Hard-Coded Configuration Information
5.4.2 Providing a Configuration File
The second way to supply configuration information is to declare all device-specific
parameters as variables that are external to your device driver. A separate small module
can declare these parameters as public variables. You can incorporate this second module
into the Bootstrap Loader by placing assembly and link commands in the first-stage
SUBMIT file BS1.CSD. To use this approach, follow the steps below:
1. In the code for the device driver, declare the device-specific parameters as external
variables. For example, the following code could be used instead of the hard-coding
shown in Figure 5-1.
name bpmsc
;Configuration information:
extrn
extrn
extrn
Bootstrap Loader
wakeup_newdrvl
device newdrvl
drtab newdrvl
word
byte
byte
;Wakeup port
; address
;Device number
;Device Table
5-7