Re: arm-elf tools problems

[yuwen <yuwen at micetek dot com dot cn>]

Kai Ruottu wrote:

> Hi,
> regarding to your problem with the arm-elf with soft-float, the following
> forwarded message should help:
>
> ------- Forwarded message follows -------
> To:             	Doug Evans <dje@sebabeach.org>
> Copies to:      	gcc-bugs@gcc.gnu.org, binutils@sources.redhat.com
> Subject:        	Re: arm-elf snafu?  can't mix default-soft-float,
> explicit
> -msoft-float
> From:           	Nick Clifton <nickc@redhat.com>
> Date sent:      	Wed, 23 Jul 2003 19:31:37 +0100
>
> [ Double-click this line for list subscription options ] 
>
> Hi Doug,
>
>  
>
> > Simple testcase:
> >
> > bash$ rm foo1.c foo2.c ; touch foo1.c foo2.c
> > bash$ arm-elf-gcc -c foo1.c
> > bash$ arm-elf-objdump -p foo1.o
> > foo1.o:     file format elf32-littlearm
> > private flags = 0: [APCS-32] [FPA float format]
> > bash$ arm-elf-gcc -c foo2.c -msoft-float
> > foo1.o:     file format elf32-littlearm
> > private flags = 200: [APCS-32] [FPA float format] [software FP]
> > bash$ arm-elf-gcc -nostdlib foo1.o foo2.o
> > [links successfully]
> > bash$ arm-elf-gcc -nostdlib foo2.o foo1.o
> > /samantha/gnu-pure/rel/lib/gcc-lib/arm-elf/3.4/../../../../arm-elf/bin/l
> > d: ERROR: foo1.o uses hardware FP, whereas a.out uses software FP
> >    
>
>  
>
> > This line in gcc/config/arm/elf.h
> >
> > #ifndef SUBTARGET_ASM_FLOAT_SPEC
> > #define SUBTARGET_ASM_FLOAT_SPEC "\
> > %{mapcs-float:-mfloat} %{msoft-float:-mfpu=softfpa}"
> > #endif
> >    
>
>
> I think that this is the problem.  If you apply the patch below for
> example, then arm-elf targets will always pass -mfpu=softfpa to GAS,
> unless -mhard-float is specfied, whereas the arm-linux toolchain will
> always pass an explicit -mfpu=fpa unless -msoft-float is specified.
>
> What do you think ?
>
> Cheers
>        Nick
>
> gcc/ChangeLog                
> 2003-07-23  Nick Clifton  <nickc@redhat.com>
>
> * config/arm/elf.h (SUBTARGET_ASM_FLOAT_SPEC): Pass
> -mfpu=softfpa to GAS by default.
> * config/arm/linux-elf.h (SUBTARGET_ASM_FLOAT_SPEC): Define.
>        Pass -mfpu=fpa to GAS by default.
>
> Index: gcc/config/arm/elf.h
> =====================================================
> ============
> ==
> RCS file: /cvs/gcc/gcc/gcc/config/arm/elf.h,v
> retrieving revision 1.44
> diff -c -3 -p -r1.44 elf.h
> *** gcc/config/arm/elf.h	19 Jun 2003 21:47:06 -0000	1.44
> --- gcc/config/arm/elf.h	23 Jul 2003 18:32:24 -0000
> ***************
> *** 46,52 ****
>
>  #ifndef SUBTARGET_ASM_FLOAT_SPEC
>  #define SUBTARGET_ASM_FLOAT_SPEC "\
> ! %{mapcs-float:-mfloat} %{msoft-float:-mfpu=softfpa}"
>  #endif
>
>  #ifndef ASM_SPEC
> --- 46,52 ----
>
>  #ifndef SUBTARGET_ASM_FLOAT_SPEC
>  #define SUBTARGET_ASM_FLOAT_SPEC "\
> ! %{mapcs-float:-mfloat} %{!mhard-float:-mfpu=softfpa}
> ! %{mhard-float:-mfpu=fpa}"
>  #endif
>
>  #ifndef ASM_SPEC
>
> Index: gcc/config/arm/linux-elf.h
> =====================================================
> ============
> ==
> RCS file: /cvs/gcc/gcc/gcc/config/arm/linux-elf.h,v
> retrieving revision 1.40
> diff -c -3 -p -r1.40 linux-elf.h
> *** gcc/config/arm/linux-elf.h	14 Jun 2003 17:11:57 -0000	1.40
> --- gcc/config/arm/linux-elf.h	23 Jul 2003 18:32:24 -0000
> ***************
> *** 40,45 ****
> --- 40,49 ----
>  #define MULTILIB_DEFAULTS \
>   { "marm", "mlittle-endian", "mhard-float", "mapcs-32",
>   "mno-thumb-interwork" }
>
> + #undef  SUBTARGET_ASM_FLOAT_SPEC
> + #define SUBTARGET_ASM_FLOAT_SPEC "\
> +   %{mapcs-float:-mfloat} %{!msoft-float:-mfpu=fpa}
> +   %{msoft-float:-mfpu=softfpa}"
> + 
>  #define CPP_APCS_PC_DEFAULT_SPEC "-D__APCS_32__"
>
>  /* The GNU C++ standard library requires that these macros be 
> defined. 
>  */
>
> ------- End of forwarded message -------
>
> I did something similar with my arm-elf tools some weeks ago and it
> definitely
> helped, the assembler needs to know the '-mfpu=softfpa' also in the
> default case, not only when '-msoft-float' was explicitly given!
>
> Cheers, Kai
>
>
>
>  
Thank you very much.  Your message is very helpful.  I'll try it.

Best regards,
Dai Yuwen



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