problems that prevented the 19990302 snapshot from running on
the efi332.
I'm happy to report that rtems-19990302 is running on the efi332
board. I have enclosed a few minor patches below to the efi332 bsp. All
patches are within that library but one. make/custom/efi332.cfg has a
patch to select the right CPU_CFLAGS (at one time -m68332 was a
problem... -mcpu32 or -m68332 work fine now).
would work. At the same time, the initial implementation of F_SETFL
was added. A support routine was added to convert internal libio
flags back to the POSIX style. Eventually the internal representation
should be eliminated in the interest of simplicity and code reduction.
This problem was reported by Jake Janovetz <janovetz@tempest.ece.uiuc.edu>.
Comments follow:
Please find attached, the updated network driver. I have verified
that it is working as expected, by timestamping the error messages
generated from the ISR.
If you've taken a look inside, the network driver has a reset thread
in addition to the RX and TX threads. It is possible to avoid the
additional reset thread by allowing the TX driver to time out and then
checking status bits set by the ISR. However, this approach demands
that a transmission is necessary for the NIC to be reset.
Due to Eric V's ISR handling, I suppose that the reset routine could
be called from the "ISR" itself, due to the 8259 interrupt mode, and
that the interrupt is acknowledged prior to running the "ISR".
(Providing that no NIC interrupts are generated during reset -- I
worry about re-entrancy. )
This would be a minor improvement, but you know, I don't want to make
this driver my lifes work.
----------------------------------------------------------------------
----------------------------------------------------------------------
> 5) rtems-rc-19990202-1.diff/reorg-install.sh
>
> reorg-install.sh fixes a Makefile variable name clash of RTEMS
> configuration files and automake/autoconf standards.
> Until now, RTEMS used $(INSTALL) for install-if-change. Automake and
> autoconf use $(INSTALL) for a bsd-compatible install. As
> install-if-change and bsd-install are not compatible, I renamed all
> references to install-if-changed to $(INSTALL_CHANGED) and used
> $(INSTALL) for bsd-install (==automake/autoconf standard). When
> automake will be introduced install-if-change will probably be replaced
> by $(INSTALL) and therefore will slowly vanish. For the moment, this
> patch fixes a very nasty problem which prevents adding any automake file
> until now (There are still more).
rather then NAME_MAX. NAME_MAX is 255 and that lets IMFS chew up memory
too fast. Perhaps in the future, the places in IMFS that put a maximum
length name string on the stack and the jnode structure does not include
a maximu length name string can be fixed so this is not a problem.
FP issues on this target:
The default variants of libc, libm and libgcc assume that a 68881
coprocessor is present. Without the FPSP, any floating point operation,
including printf() with a "%f" format specifier, is likely to cause an
unimplemented instruction exception.
The FPSP works with the default variants of libc, libm and libgcc. It does not
work in conjunction with the msoft-float variants. The paranoia test goes into
an infinite loop at milestone 40. I am guessing that floor() is returning an
incorrect value.
The msoft-float variants of libc, libm and libgcc appear to do floating point
I/O properly. They only failed in paranoia. Offhand, I can't think of why they
would conflict with the FPSP, so I think that there is something wrong with the
msoft-float code. It might be my installation.
Given my experiences, I decided to install the FPSP in bsp_start(), and to link
against the default variants of libc, libm and libgcc. This causes the
executables to increase in size by about 60 KB. The README file and the
mvme167.cfg specify how to remove the FPSP, and how to link against the
msoft-float variants of the libraries. This is not what Eric Norum had done: on
my host, his gen68360_040 port links RTEMS code with the msoft-float variants
of libc and libm, and the default variant of libgcc. In this configuration, the
output of printf() with "%f" is garbage on my target.
FP issues on this target:
The default variants of libc, libm and libgcc assume that a 68881
coprocessor is present. Without the FPSP, any floating point operation,
including printf() with a "%f" format specifier, is likely to cause an
unimplemented instruction exception.
The FPSP works with the default variants of libc, libm and libgcc. It does not
work in conjunction with the msoft-float variants. The paranoia test goes into
an infinite loop at milestone 40. I am guessing that floor() is returning an
incorrect value.
The msoft-float variants of libc, libm and libgcc appear to do floating point
I/O properly. They only failed in paranoia. Offhand, I can't think of why they
would conflict with the FPSP, so I think that there is something wrong with the
msoft-float code. It might be my installation.
Given my experiences, I decided to install the FPSP in bsp_start(), and to link
against the default variants of libc, libm and libgcc. This causes the
executables to increase in size by about 60 KB. The README file and the
mvme167.cfg specify how to remove the FPSP, and how to link against the
msoft-float variants of the libraries. This is not what Eric Norum had done: on
my host, his gen68360_040 port links RTEMS code with the msoft-float variants
of libc and libm, and the default variant of libgcc. In this configuration, the
output of printf() with "%f" is garbage on my target.
is long but I hate to lose the information so I am including it here.
> I am still fixing and recompiling but this is the issue that was not the
> result of another patch. This is a fundamental build issue that I value
> your opinion on.
This is difficult issue (I.e. I have no destinct solution for it)
Background:
(gnu-) make's implicit rules apply CFLAGS, CPPFLAGS, CXXFLAGS, ASFLAGS and
LDFLAGS (cf. make.info/Implicit Rules/Catalogue of Rules), only.
In brief:
CPPFLAGS .. passed to the c-preprocessor
CFLAGS ... passed to the c-compiler
CXXFLAGS ... equivalent to CFLAGS but passed to the c++ compiler
(Attention: CFLAGS is not passed to the c++ compiler)
ASFLAGS .. equivalent to CFLAGS, but passed to the assembler
LDFLAGS .. equivalent to CFLAGS, but passed to the linker
A bit oversimplifying, these make rules are as follows
.c.o:
$(CC) $(CPPFLAGS) $(CFLAGS) -c
.cc.o:
$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c
.S.s:
$(CPP) $(CPPFLAGS)
.s.o:
$(AS) $(ASFLAGS)
My reading of the documentation (make.info) is that {AS|AR|CC|CXX|CPP}FLAGS
are ment to be passed to the related tools directly, however examinating
the rule set of gmake (gmake -p -f /dev/null") shows that many rules use
$(CC) instead of the related tools (eg. linker rules) etc.
I.e. these flags should not rely on being passed through cpp or gcc. With
gcc being the common frontend for all of these tools of a gnu-toolchain the
situation becomes difficult (Which option is passed to whom and which tool
really uses it?), because these variable can also contain the toolchain's
frontend (eg. AS=gcc, LD=gcc, CPP=gcc -E).
For some commonly used options the situation is quite clear:
* -g -> CFLAGS
* -OX -> CFLAGS
* -D -> CPPFLAGS
* -A -> CPPFLAGS
But where to add -m, -B, -specs, -qrtems_XXX ?
* -B, -specs, -qrtems_XXX are gcc-frontend options
* -m is a combinations of flags to go to different destinations, in many
(all?) cases, the following is valid
-m is expanded by gcc into a set of -D and -A options
-m is interpreted by cc1 as a machine flag to generate a specific
instruction set.
-m is interpreted by gcc as an implicit linker search path for multilibs to
set up calls to LD.
>From my point of view this indicates we can either destingush between these
different usages (= separately add -m to CFLAGS, LDFLAGS etc) or to add it
to CPPFLAGS and use gcc (the frontend) instead of calling each tool
directly (less error prone) -- I vote for CPPFLAGS, but I am not sure.
-----------------
Now, where to add CPU_CFLAGS?
AFAIS, in probably all cases CPU_CFLAGS contain -D -A, and -m options,
only.
* -D and -A are supposed to go to CPPFLAGS
* -mXXX options can have multiple meanings (It can be gcc, collect2/ld and
cc1/cc1plus option simultaneously)
Here, I made a mistake - I destinguished between CPU_DEFINES to be added to
CPPFLAGS and CPU_CFLAGS to be added to CFLAGS and CXXFLAGS (cf.
gcc-target-default.cfg), generally assuming CPU_CFLAGS are CFLAGS.
This breaks preprocessing *.S into *.i files because CPU_CFLAGS flags were
not added to CPPFLAGS. Hence *all* *.S were compiled without taking
-mXX-flags into account. The i960/cvme BSP was the only one which
explicitly checked for a specific -m flag (-mca) and refused to compile
without it -- all other CPUs/BSPs silently swallowed this.
IMO, we can either
1) add CPU_CFLAGS and CPU_DEFINES to CPPFLAGS, thus silently convert
CPU_CFLAGS's meaning into CPU_DEFINES (Alternative solution: rename
CPU_CFLAGS to CPU_DEFINES and merge CPU_FLAGS with CPU_DEFINES).
or
2) destinguish between CPU_DEFINES and CPU_CFLAGS. In this case we would
need to check the contents of each CPU_CFLAGS in custom/*.cfg and move the
some parts of the contents to CPU_DEFINES and keep other parts in
CPU_CFLAGS (CFLAGS must contain options for the c/c++-compiler only!).
Though Solution 2) is the clearer one, I implemented 1) which is the
simplier one (the patch below).
ATTENTION: This patch is small in size, but affects almost everything.
------------
Additional complications araise with linking:
Some BSPs call LD and AS directly (esp. gcc-2.7 make-exe rules). If LD=gcc
then LDFLAGS are supposed to be gcc-options, but if LD=ld then LDFLAGS is
supposed to contain ld-options.
An analog thought is valid for AS, but luckily enough ASFLAGS is not used
of inside the whole source tree.
Most RTEMS' custom/*.cfg use $(CC) $(CFLAGS) to link with gcc-2.8 make-exe
rules. With the patch below (CPU_CFLAGS added to CPPFLAGS) this means
CPU_CFLAGS will not be passed to the linker, which is incorrect for
multilibbed CPU's.
gmake's default rule set contains a variety of rules for linking, all
ending up in calling $(CC) $(LDFLAGS) for linking at their very end.
IMO, this means we should use something like
LINK.o = $(CC) $(LDFLAGS) in gcc-target-default.cfg
+ modify all gcc-2.8 make-exe rules to use
$(LINK.o) .......
+ setup LDFLAGS according to the requirements of the above.
I.e. we should use $(CC) for linking instead of calling the linker (LD)
directly and set LDFLAGS = $(CPPFLAGS) $(CFLAGS) or similar.
