6.3.2.1 General Information

At the top of the map file is general information relating to the execution of the linker.

When analyzing a program, always confirm the assembler version number shown at the very top of the map file to ensure you are using the assembler you intended to use.

The device selected with the -mcpu option (see 3.4.15 Cpu Option), or the one selected in your IDE, should appear after the Machine type entry.

The object code version relates to the file format used by relocatable object files produced by the assembler. Unless either the assembler or linker have been updated independently, this should not be of concern.

A typical map file might begin something like the following cut down example.

Linker command line:
--edf=/Applications/Microchip/XC8/2.20/dat/en_msgs.txt -cs -h+main.sym -z \
-Q16F946 -ol.o -Mmain.map -ver=XC8 -ACONST=00h-0FFhx32 \
-ACODE=00h-07FFhx4 -ASTRCODE=00h-01FFFh -AENTRY=00h-0FFhx32 \
-ASTRING=00h-0FFhx32 -ACOMMON=070h-07Fh -ABANK0=020h-06Fh \
-ABANK1=0A0h-0EFh -ABANK2=0120h-016Fh -ABANK3=01A0h-01EFh \
-ARAM=020h-06Fh,0A0h-0EFh,0120h-016Fh,01A0h-01EFh \
-AABS1=020h-07Fh,0A0h-0EFh,0120h-016Fh,01A0h-01EFh -ASFR0=00h-01Fh \
-ASFR1=080h-09Fh -ASFR2=0100h-011Fh -ASFR3=0180h-019Fh \
-preset_vec=00h,intentry,init,end_init -ppowerup=CODE -pfunctab=CODE \
-ACONFIG=02007h-02007h -pconfig=CONFIG -DCONFIG=2 -AIDLOC=02000h-02003h \
-pidloc=IDLOC -DIDLOC=2 -AEEDATA=00h-0FFh/02100h -peeprom_data=EEDATA \
-DEEDATA=2 -DCODE=2 -DSTRCODE=2 -DSTRING=2 -DCONST=2 -DENTRY=2 -k \
startup.o main.o

Object code version is 3.10

Machine type is 16F946

The information following Linker command line: shows all the command-line options and files that were passed to the linker for the last build. Remember, these are linker options, not command-line driver options.

The linker options are necessarily complex. Fortunately, they rarely need adjusting from their default settings. They are formed by the command-line driver, pic-as, based on the selected target device and the specified driver options. You can often confirm that driver options were valid by looking at the linker options in the map file. For example, if you ask the driver to reserve an area of memory, you should see a change in the linker options used.

If the default linker options must be changed, this can be done indirectly through the driver using the driver -Wl option (see 3.4.36 Wl: Pass Option To The Linker, Option). If you use this option, always confirm the change appears correctly in the map file.