Den 25-05-2012 13:54, Jonas Maebe skrev:
Fuxin Zhang wrote on Fri, 25 May 2012:
And my progress and problems:
I've got the source from subversion and tried to build it in ubuntu
11.10 x86-64 machine. With the following patch and commands, I can get a
partly working ppcrossmipsel(it can at least build a helloworld and
runnable):
patch:
Index: Makefile.fpc
===================================================================
--- Makefile.fpc (版本 21354)
+++ Makefile.fpc (工作副本)
[snip]
This is to fix various file not found errors. I am not sure whether
it is
'right' fix.
No, definitely it's definitely not right. It's strange that you need
those changes, since the Linux RTL Makefile is used daily. Did you
need those changes even to compile it for i386?
commands:
cd rtl/linux;
patch Makefile.fpc; fpcmake -Ti386-linux,mipsel-linux
It's better to use -Tall (since there are more Linux targets than just
i386 and mipsel).
/home/foxsen/fpc/rtl/units/mipsel-linux/sysutils.o: In function
`SYSUTILS_$$_finalize':
/home/foxsen/fpc/rtl/unix/sysutils.pp:1414: relocation truncated to fit:
R_MIPS_PC16 against
`SYSTEM$_$TINTERFACEDOBJECT_$__$$_QUERYINTERFACE$TGUID$formal$$LONGINT'
/home/foxsen/fpc/rtl/unix/sysutils.pp:1414: relocation truncated to fit:
R_MIPS_PC16 against `SYSTEM$_$TINTERFACEDOBJECT_$__$$__ADDREF$$LONGINT'
/home/foxsen/fpc/rtl/unix/sysutils.pp:1414: relocation truncated to fit:
R_MIPS_PC16 against `SYSTEM$_$TINTERFACEDOBJECT_$__$$__RELEASE$$LONGINT'
pp.pas(224,36) Error: Error while linking
pp.pas(224,36) Fatal: There were 1 errors compiling module, stopping
Fatal: Compilation aborted> make[1]: *** [ppcmipsel] 错误 1
make[1]:正在离开目录 `/home/foxsen/fpc/compiler'
make: *** [cycle] 错误 2
I know it is related to mips branch offset overflow.
A similar issue exists on PowerPC: conditional branches are limited to
16 bit offsets, while unconditional branches can reach up to 26 bits
or so. As far as I can see, it's similar on MIPS (the B* opcodes
versus the J opcode). If so, you may be able to create a MIPS version
of the fixup_jmps procedure in compiler/ppcgen/aasmcpu.pas and add it
to compiler/mips/aasmcpu.pas (it's called from psub.pas, you'll have
to modify the ifdef there to also activate it for MIPS and MIPSEL).
The actual errors you get are strange though. We never insert
conditional branches from one routine to another (in the above case:
from SYSUTILS_$$_finalize, or more likely from interface wrappers
following that symbol, to various other routines). Looking at the code
for tcgcpu.g_intf_wrapper in compiler/mips/cgcpu.pas, the code for
interface wrappers uses the "B" as opposed to the "J" instruction to
branch to the interface wrappers. Maybe that's a copy/paste error from
another platform. I'm not sure what "B" means though, I don't see it
listed at http://www.mrc.uidaho.edu/mrc/people/jff/digital/MIPSir.html
Anyway, I guess this patch will solve the above error:
Index: compiler/mips/cgcpu.pas
===================================================================
--- compiler/mips/cgcpu.pas (revision 21359)
+++ compiler/mips/cgcpu.pas (working copy)
@@ -1722,7 +1722,7 @@
op_onr24methodaddr;
end
else
-
list.concat(taicpu.op_sym(A_B,current_asmdata.RefAsmSymbol(procdef.mangledname)));
+
list.concat(taicpu.op_sym(A_J,current_asmdata.RefAsmSymbol(procdef.mangledname)));
{ Delay slot }
list.Concat(TAiCpu.Op_none(A_NOP));
After some
research,I've found that ppc code support -fPIC.
PIC normally won't help with branch offset overflows.
But when I try to enable
it,the other issue appears:
Yes, PIC requires cpu-specific support. It shouldn't be necessary to
get an initial port up and running though.
Jonas
I wonder how you people managed to build anything at all.
When I tried to build from SVN trunk there would be an endless steam of
internalerrors related to fpu registers, no matter if compiled with MIPS
FPU or softfloat.
I managed to remove the errors with the following patch, such that
everything compiled, but I haven't been able to test it:
http://j-software.dk/fpc-mipsel.patch
Does anyone know if there's an easy way to set up an emulator for
testing? Been fighting with qemu for the last half hour without results.
Regards,
Jeppe
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