Re: [fpc-devel] Regarding issue/patch 0032637
Would code like this be correct?
Procedure FillWord(var x; count: SizeInt; value: Word); assembler; nostackframe;
asm
{ win64: rcx dest, rdx count, r8w value
linux: rdi dest, rsi count, dx value }
{$ifdef win64}
push%rdi
.seh_pushreg %rdi
.seh_endprologue
cmp $0x0, %rdx
...
I recall now an assembler routine where RBX was modified midway through a
procedure, but instead of pushing
and popping it, it was written to a reserved part of the stack (configured in
the prologue) and given a
.seh_savereg hint - still trying to get my head around all of this!
Kit
On Thu 30/11/17 04:26 , "J. Gareth Moreton" gar...@moreton-family.com sent:
> Ooh right, okay. Thanks for that Sergei. I just put it in somewhat
> blindly because the compiler inserts it
> for Pascal code after the normal prologue after creating a stack frame, but
> complained and threw an error if
> I used .seh_pushreg but then neglected to use .seh_endprologue. I agree
> that the compiler should complain
> if it finds things out of order like I did, otherwise one may not know any
> better.
>
>
> I'm still learning the nuances! I'll just fix my code.
>
>
>
> Gareth aka. Kit
>
>
>
> P.S. Is there any way to remove the other patches from that bug report.
>
>
>
> P.P.S. Would you be able to say my advice was plain wrong on the forum post
> and correct it, just for the
> sake of anyone else who stumbles across it.
>
>
>
> P.P.P.S. Any possibility of inserting similar functionality for Intel-style
> assembler at some point?
>
>
>
>
>
>
> On Wed 29/11/17 14:58 , "Sergei Gorelkin via fpc-devel"
> fpc-devel@lists.freepascal.org sent:
> >
>
> >
>
> >
>
> >
>
> > 29.11.2017 15:12, J. Gareth Moreton wrote:
>
> >
>
> > > Thanks Christo.
>
> >
>
> > >
>
> >
>
> > > Apologies for 4 messages coming in at once.
> I
> > think there were a few technical glitches with
> the mailing
> > > list. Either way, I have submitted an
> updated
> > patch to the bug report in question that
> corrects the stack
> > > unwinding for Windows. Any testing would
> be
> > greatly appreciated (I'm not in a position to
> rigorously test
> > > the code for Linux).
>
> >
>
> > >
>
> >
>
> > > Yeah, I got a little emotional with
> Thaddy's
> > response (which has since been deleted), partly
> because he
> > > mocked me a bit for even attempting to use
>
> > assembly language for optimisation. Granted, I
> tend to do more
> > > low-level and mathematical programming than
>
> > higher-level components, where assembler
> optimisation can really
> > > pay dividends. Plus in a perverted way, I
>
> > actually enjoy trying to squeeze another
> microsecond out of
> > > running time!
>
> >
>
> > >
>
> >
>
> > > Gareth aka. Kit.
>
> >
>
> > >
>
> >
>
> >
>
> >
>
> > I should have read and answered earlier, but
> better late than never.
> >
>
> >
>
> >
>
> > The x86-64 target (actually, all targets except
> i386 and m68k) use concept
> > of fixed stack. This
>
> > means: all changes to the stack pointer are done
> at the beginning and at
> > the end of procedure.
>
> > Pushing something in the middle is illegal. The
> stack pointer itself needs
> > to be aligned only at the
>
> > point of calling another procedure. As a
> consequence, simple procedures
> > that don't call other
>
> > procedures and don't use nonvolatile registers
> can have the stack pointer
> > misaligned by 8 bytes as
>
> > it naturally is at the first instruction (such
> procedures don't need any
> > SEH annotations at all,
>
> > which is a way to simplify things).
>
> >
>
> > Now, several first instructions where is stack
> pointer is changed and
> > nonvolatile registers are
>
> > saved is called prologue. It is delimited by
> .seh_endprologue directive and
> > can be at most 255 bytes
>
> > in size.
>
> >
>
> > The advice given at forum to insert
> .seh_endprologue at the very beginning
> > is plain wrong.
>
> > .seh_endprologue must be the last SEH directive
> in procedure. Compiler
> > probably needs to do more
>
> > checks and reject SEH directives coming after
> .seh_endprologue.
> >
>
> >
>
> >
>
> > Regards,
>
> >
>
> > Sergei
>
> >
>
> >
>
> >
>
> > ___
>
> >
>
> > fpc-devel maillist - fpc-devel@lists.freepascal.org
> > http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
> >
>
> >
>
> >
>
> >
>
>
>
> ___
>
> fpc-devel maillist - fpc-devel@lists.freepascal.org
> http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
>
>
>
>
___
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
Re: [fpc-devel] Regarding issue/patch 0032637
Ooh right, okay. Thanks for that Sergei. I just put it in somewhat blindly because the compiler inserts it for Pascal code after the normal prologue after creating a stack frame, but complained and threw an error if I used .seh_pushreg but then neglected to use .seh_endprologue. I agree that the compiler should complain if it finds things out of order like I did, otherwise one may not know any better. I'm still learning the nuances! I'll just fix my code. Gareth aka. Kit P.S. Is there any way to remove the other patches from that bug report. P.P.S. Would you be able to say my advice was plain wrong on the forum post and correct it, just for the sake of anyone else who stumbles across it. P.P.P.S. Any possibility of inserting similar functionality for Intel-style assembler at some point? On Wed 29/11/17 14:58 , "Sergei Gorelkin via fpc-devel" fpc-devel@lists.freepascal.org sent: > > > > > 29.11.2017 15:12, J. Gareth Moreton wrote: > > > Thanks Christo. > > > > > > Apologies for 4 messages coming in at once. I > think there were a few technical glitches with the mailing > > list. Either way, I have submitted an updated > patch to the bug report in question that corrects the stack > > unwinding for Windows. Any testing would be > greatly appreciated (I'm not in a position to rigorously test > > the code for Linux). > > > > > > Yeah, I got a little emotional with Thaddy's > response (which has since been deleted), partly because he > > mocked me a bit for even attempting to use > assembly language for optimisation. Granted, I tend to do more > > low-level and mathematical programming than > higher-level components, where assembler optimisation can really > > pay dividends. Plus in a perverted way, I > actually enjoy trying to squeeze another microsecond out of > > running time! > > > > > > Gareth aka. Kit. > > > > > > > I should have read and answered earlier, but better late than never. > > > > The x86-64 target (actually, all targets except i386 and m68k) use concept > of fixed stack. This > means: all changes to the stack pointer are done at the beginning and at > the end of procedure. > Pushing something in the middle is illegal. The stack pointer itself needs > to be aligned only at the > point of calling another procedure. As a consequence, simple procedures > that don't call other > procedures and don't use nonvolatile registers can have the stack pointer > misaligned by 8 bytes as > it naturally is at the first instruction (such procedures don't need any > SEH annotations at all, > which is a way to simplify things). > > Now, several first instructions where is stack pointer is changed and > nonvolatile registers are > saved is called prologue. It is delimited by .seh_endprologue directive and > can be at most 255 bytes > in size. > > The advice given at forum to insert .seh_endprologue at the very beginning > is plain wrong. > .seh_endprologue must be the last SEH directive in procedure. Compiler > probably needs to do more > checks and reject SEH directives coming after .seh_endprologue. > > > > Regards, > > Sergei > > > > ___ > > fpc-devel maillist - fpc-devel@lists.freepascal.org > http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel > > > > ___ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
Re: [fpc-devel] AVR - assembler error when compiling large files
On Tue, 2017-11-28 at 20:08 +0100, Florian Klämpfl wrote: > Am 25.11.2017 um 22:19 schrieb Christo: > > > > On Sat, 2017-11-25 at 18:27 +0100, Florian Klämpfl wrote: > > > > > > What happens if you compile them with -CX? > > Same problem. > > > > > > > > > > > > > Is there a way to instruct the compiler to use a larger data > > > > type > > > > when > > > > emitting this information to the assembler file? > > > This makes no sense as the program code using this data would not > > > know about this. > > That was a clue to show I'm in unfamiliar territory. > > > > I experienced the problem when using the supplied make file to > > build an > > AVR RTL. When I compiled the unit by hand, it worked. I then > > noticed > > that the problem seems to be related to the -g option. If I > > compile > > the large unit with -gw3 it was fine but when I compile the large > > unit > > with -g it gave the "Error: value of 65611 too large for field of 2 > > bytes at 65609" type errors. > > > > I tried passing OPT=-gw3 to make, but then the system unit cannot > > compile. Unfortunately this means I cannot use the current makefile > > to > > compile AVR RTL with large unit files. > What command line do you use? I'm compiling the RTL with ppcrossavr, so I follow the sequence from the make file from source folder rtl/embedded. First step: [path]/ppcrossavr -Cpavr5 @rtl.cfg -Ur -Tembedded -Pavr -XPavr- -Xr -Ur -Xs -O2 -n -Fi../inc -Fi../avr -FE. -FU../../rtl/units/avr-embedded -davr -dRELEASE -Us -Sg system.pp Then: [path]/ppcrossavr -Cpavr5 @rtl.cfg -Ur -Tembedded -Pavr -XPavr- -Xr -Ur -Xs -O2 -n -Fi../inc -Fi../avr -FE. -FU../../rtl/units/avr-embedded -davr -dRELEASE ../avr/intrinsics.pp Then a shortish unit (1363 lines): [path]/ppcrossavr -Cpavr5 @rtl.cfg -Ur -Tembedded -Pavr -XPavr- -Xr -Ur -Xs -O2 -n -Fi../inc -Fi../avr -FE. -FU../../rtl/units/avr-embedded -davr -dRELEASE -g avr/atmega328p.pp Then a long unit (2425 lines of code): [path]/ppcrossavr -Cpavr5 @rtl.cfg -Ur -Tembedded -Pavr -XPavr- -Xr -Ur -Xs -O2 -n -Fi../inc -Fi../avr -FE. -FU../../rtl/units/avr-embedded -davr -dRELEASE -g avr/atmega32u4.pp I then get the stated errors for atmega32u4.pp and other "large" files. The differences in content between the file that compiles/assemble and the one that doesn't is similar, there is just more of the same declarations in the file because the controller has more hardware registers. I can compile atmega32u4.pp by using the following: [path]/ppcrossavr -Cpavr5 @rtl.cfg -Ur -Tembedded -Pavr -XPavr- -Xr -Ur -Xs -O2 -n -Fi../inc -Fi../avr -FE. -FU../../rtl/units/avr-embedded -davr -dRELEASE -gw3 avr/atmega32u4.pp So simply switching to dwarf3 fixes the assembler problem (error while assembling). ___ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
Re: [fpc-devel] Regarding issue/patch 0032637
29.11.2017 15:12, J. Gareth Moreton wrote: Thanks Christo. Apologies for 4 messages coming in at once. I think there were a few technical glitches with the mailing list. Either way, I have submitted an updated patch to the bug report in question that corrects the stack unwinding for Windows. Any testing would be greatly appreciated (I'm not in a position to rigorously test the code for Linux). Yeah, I got a little emotional with Thaddy's response (which has since been deleted), partly because he mocked me a bit for even attempting to use assembly language for optimisation. Granted, I tend to do more low-level and mathematical programming than higher-level components, where assembler optimisation can really pay dividends. Plus in a perverted way, I actually enjoy trying to squeeze another microsecond out of running time! Gareth aka. Kit. I should have read and answered earlier, but better late than never. The x86-64 target (actually, all targets except i386 and m68k) use concept of fixed stack. This means: all changes to the stack pointer are done at the beginning and at the end of procedure. Pushing something in the middle is illegal. The stack pointer itself needs to be aligned only at the point of calling another procedure. As a consequence, simple procedures that don't call other procedures and don't use nonvolatile registers can have the stack pointer misaligned by 8 bytes as it naturally is at the first instruction (such procedures don't need any SEH annotations at all, which is a way to simplify things). Now, several first instructions where is stack pointer is changed and nonvolatile registers are saved is called prologue. It is delimited by .seh_endprologue directive and can be at most 255 bytes in size. The advice given at forum to insert .seh_endprologue at the very beginning is plain wrong. .seh_endprologue must be the last SEH directive in procedure. Compiler probably needs to do more checks and reject SEH directives coming after .seh_endprologue. Regards, Sergei ___ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
Re: [fpc-devel] Regarding issue/patch 0032637
Thanks Christo. Apologies for 4 messages coming in at once. I think there were a few technical glitches with the mailing list. Either way, I have submitted an updated patch to the bug report in question that corrects the stack unwinding for Windows. Any testing would be greatly appreciated (I'm not in a position to rigorously test the code for Linux). Yeah, I got a little emotional with Thaddy's response (which has since been deleted), partly because he mocked me a bit for even attempting to use assembly language for optimisation. Granted, I tend to do more low-level and mathematical programming than higher-level components, where assembler optimisation can really pay dividends. Plus in a perverted way, I actually enjoy trying to squeeze another microsecond out of running time! Gareth aka. Kit. On Wed 29/11/17 05:19 , Christo christo.cra...@gmail.com sent: > On Sun, 2017-11-26 at 09:29 +, J. Gareth Moreton wrote: > > > I'm guessing my code is not correct or causes > problems. I haven't > > had much luck in finding a straight answer > > > regarding proper exception handling with > assembler code (where > > correcting non-volatile registers and > stack > > space are concerned), although I'll keep > trying. I tried asking on > > the forum, but Thaddy gave me a response > > > that is somewhat discouraging. > > > > Thaddy has a somewhat unique perspective of things. As per normal when > > reading things on the internet, try to recognize the difference between > > fact and opinion. Facts are very useful, opinions are sometimes > useful > (if the person has a good overview of the subject matter) but can also > > reflect a person's bias. > > > > > ___ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
