Page 238 - Programming Microcontrollers in C

Header File 223

#
# link command file for motorfr program
#
+h # multi-segment output
-o motorfr.h11 # output file name
+text -b 0xd000 # program start address
+data -b 0x0000 # data start address
crtsmot.o # start-up routine
motorfr.o # application program
libi.h11 # integer library
libm.h11 # machine library
+text -b 0xffd6 # vectors start address
interrup.o # interrupt vectors
+def __memory=__bss__ # symbol used by library

Comment lines are preceded with a # in this command file. The
first executable line of code in the file contains a command +h which
notifies the linker that the program will be in multiple memory
segments rather than in a single block in memory. The second line

-o motorfr.h11
tells the linker to write the output file to motorfr.h11. This
particular linker file is for a program named motorfr. The +text
option places the beginning of the code portion of the next module to
be linked at the offset 0xd000. The +data option places the data
memory for the next module at the offset 0x0000. Finally, the names
of the modules to be linked are next. The module crtsmot.o is a
relocatable object module version of a start-up program. This routine
will be discussed below. The next module to be linked is motorfr.o
which is the output of the compiler. This line is followed by the
invocation of two library calls. The first is to the integer library, and
the second is to the machine library. These libraries will provide
necessary code for function calls that are not contained directly in
the program. Another library named libf.h11 contains floating
point operations that might be needed in your program.
Another +text option will force the beginning of the code linked
next to the address 0xffd6. This address is the beginning of the
MC68HC11 vector table, and the code linked at this point is the vector
function discussed earlier. This entry will create the vector table at