[RFA] replace stub fn mips_eabi_return_value

[Michael Snyder]

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Michael Snyder wrote:
> ... just as Fred Fish recently did for the o64 version.
> 
> 
> ------------------------------------------------------------------------
> 
> 2006-05-31  Michael Snyder  <msnyder@redhat.com>
> 
> 	* mips-tdep.c (mips_eabi_return_value): Replace stub that always
> 	returned RETURN_VALUE_STRUCT_CONVENTION with a real function.
> 
> Index: mips-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/mips-tdep.c,v
> retrieving revision 1.393
> diff -p -r1.393 mips-tdep.c
> *** mips-tdep.c	31 May 2006 23:15:50 -0000	1.393
> --- mips-tdep.c	31 May 2006 23:52:56 -0000
> *************** mips_eabi_return_value (struct gdbarch *
> *** 2651,2664 ****
>   			struct type *type, struct regcache *regcache,
>   			gdb_byte *readbuf, const gdb_byte *writebuf)
>   {
>     if (TYPE_LENGTH (type) > 2 * mips_abi_regsize (gdbarch))
>       return RETURN_VALUE_STRUCT_CONVENTION;
> !   if (readbuf)
> !     memset (readbuf, 0, TYPE_LENGTH (type));
>     return RETURN_VALUE_REGISTER_CONVENTION;
>   }
>   
> - 
>   /* N32/N64 ABI stuff.  */
>   
>   static CORE_ADDR
> --- 2651,2712 ----
>   			struct type *type, struct regcache *regcache,
>   			gdb_byte *readbuf, const gdb_byte *writebuf)
>   {
> +   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +   int fp_return_type = 0;
> +   int offset, regnum, xfer;
> + 
>     if (TYPE_LENGTH (type) > 2 * mips_abi_regsize (gdbarch))
>       return RETURN_VALUE_STRUCT_CONVENTION;
> ! 
> !   /* Floating point type?  */
> !   if (tdep->mips_fpu_type != MIPS_FPU_NONE)
> !     {
> !       if (TYPE_CODE (type) == TYPE_CODE_FLT)
> ! 	fp_return_type = 1;
> !       /* Structs with a single field of float type 
> ! 	 are returned in a floating point register.  */
> !       if ((TYPE_CODE (type) == TYPE_CODE_STRUCT
> ! 	   || TYPE_CODE (type) == TYPE_CODE_UNION)
> ! 	  && TYPE_NFIELDS (type) == 1)
> ! 	{
> ! 	  struct type *fieldtype = TYPE_FIELD_TYPE (type, 0);
> ! 
> ! 	  if (TYPE_CODE (check_typedef (fieldtype)) == TYPE_CODE_FLT)
> ! 	    fp_return_type = 1;
> ! 	}
> !     }
> ! 
> !   if (fp_return_type)      
> !     {
> !       /* A floating-point value belongs in the least significant part
> !          of FP0/FP1.  */
> !       if (mips_debug)
> ! 	fprintf_unfiltered (gdb_stderr, "Return float in $fp0\n");
> !       regnum = mips_regnum (gdbarch)->fp0;
> !     }
> !   else 
> !     {
> !       /* An integer value goes in V0/V1.  */
> !       if (mips_debug)
> ! 	fprintf_unfiltered (gdb_stderr, "Return scalar in $v0\n");
> !       regnum = MIPS_V0_REGNUM;
> !     }
> !   for (offset = 0;
> !        offset < TYPE_LENGTH (type);
> !        /* offset += register_size (gdbarch, regnum), regnum++) */
> !        offset += mips_stack_argsize (gdbarch), regnum++)
> !     {
> !       /* xfer = register_size (gdbarch, regnum); */
> !       xfer = mips_stack_argsize (gdbarch);
> !       if (offset + xfer > TYPE_LENGTH (type))
> ! 	xfer = TYPE_LENGTH (type) - offset;
> !       mips_xfer_register (regcache, NUM_REGS + regnum, xfer,
> ! 			  TARGET_BYTE_ORDER, readbuf, writebuf, offset);
> !     }
> ! 
>     return RETURN_VALUE_REGISTER_CONVENTION;
>   }
>   
>   /* N32/N64 ABI stuff.  */
>   
>   static CORE_ADDR