[En-Nut-Discussion] Assembly listings (.lst) placed in source directories

[José Vallet]

Hello all.

.lst files are placed in the the source directories, at least in the 
example applications provided by NutOS (4.8.5). This becomes a problem 
if we want to separate source and compilation related files by, for 
example, creating a build directory.

To illustrate the problem, let's take the hello_world application 
example and create a build directory

What I do:
1-Create the bld directory in nutapp/hello_world
2-Move the Makefile to the bld directory
3-Modify the Makefile as:
--------
...
VPATH = ../
...
include ../../Makedefs
...
include ../../Makerules
--------

Then I call make from the bld directory.

The problem is that the .lst files remain in the source directory, and 
thus making it to appear "dirty". Also, calling "make clean" does not 
remove the .lst file from the source directory, and therefore additional 
commands have to be written in the application's clean target to take 
care of deleting them.

If I am not mistaken, the assembler options used by the apps are defined 
in the CPFLAGS make variable in nut/app/Makerules.arm-gcc (for arm and 
gcc), which reads
----------------
CPFLAGS   = $(MCFLAGS) -Os -mthumb-interwork -fomit-frame-pointer -Wall 
-Wstrict-prototypes -fverbose-asm -Wa,-ahlms=$(<:.c=.lst) $(DEFS)
----------------
Note that there is a previous definition in nut/Makedefs.arm-gcc, which 
is included by nut/app/Makerules.arm-gcc, but it is overridden by the 
definition in the later one.

It seems that make substitutes "<" by "../uart.c", and therefore the 
substitution of "$(<:.c=.lst)" leads to "../uart.lst", which basically 
tells the assembler to store the .lst with the sources. If we change 
"-Wa,-ahlms=$(<:.c=.lst)" to "-Wa,-ahlms=$(@:.o=.lst)" as it appears in 
nut/Makedefs.arm-gcc, make substitutes it by "uart.o", and finally the 
.lst appears in the bld directory. Then also "make clean" works as it is 
supposed to.

My questions:
1-Are the .lst files left in the source file directories on purpose for 
any specific reason that I ignore?
2-If not, would it be possible to keep them in a hypothetical build 
directory with the rest of the compilation-produced files?
3-If so, is the above proposed solution valid?
4-Why the CPFLAGS definition in nut/Makedefs.arm-gcc is overridden later 
in nut/app/Makerules.arm-gcc?

And as always, if I am missing something any explanation is welcomed.

Thanks and regards
José