Re: [commit] 128-bit long double for mips64-linux

[Mark Kettenis <mark dot kettenis at xs4all dot nl>]

> Date: Wed, 15 Mar 2006 11:45:07 -0500
> From: Daniel Jacobowitz <drow@false.org>
> 
> This patch adds support for the IEEE 128-bit long double format used
> on MIPS/Linux.  IRIX does something different, so I didn't touch that
> (I can't test IRIX).
> 
> There's something fishy about floating point results on N32 in my latest
> testing, but this is still an improvement - without it we get errors
> trying to print 128-bit types for which we have no floatformat set.
> 
> Tested on mips64-linux and committed.

What's up with the mips-tdep.c change?  Your ChangeLog doesn't mention
it, but it seems you committed it.

> 
> -- 
> Daniel Jacobowitz
> CodeSourcery
> 
> 2006-03-15  Daniel Jacobowitz  <dan@codesourcery.com>
> 
> 	* mips-linux-tdep.c: Include "floatformat.h".
> 	(mips_linux_init_abi): Use 128-bit long double for N32 and N64.
> 	(mips_n32n64_return_value): Support 128-bit long double.
> 	(print_gp_register_row): Don't print spaces before ignored
> 	or floating point registers.
> 
> Index: src/gdb/mips-linux-tdep.c
> ===================================================================
> --- src.orig/gdb/mips-linux-tdep.c	2006-03-14 15:44:19.000000000 -0500
> +++ src/gdb/mips-linux-tdep.c	2006-03-14 16:48:33.000000000 -0500
> @@ -32,6 +32,7 @@
>  #include "regcache.h"
>  #include "trad-frame.h"
>  #include "tramp-frame.h"
> +#include "floatformat.h"
>  
>  /* Copied from <asm/elf.h>.  */
>  #define ELF_NGREG       45
> @@ -1110,6 +1111,15 @@ mips_linux_init_abi (struct gdbarch_info
>  	set_solib_svr4_fetch_link_map_offsets
>  	  (gdbarch, svr4_ilp32_fetch_link_map_offsets);
>  	set_mips_linux_register_addr (gdbarch, mips64_linux_register_addr);
> +	set_gdbarch_long_double_bit (gdbarch, 128);
> +	/* These floatformats should probably be renamed.  MIPS uses
> +	   the same 128-bit IEEE floating point format that IA-64 uses,
> +	   except that the quiet/signalling NaN bit is reversed (GDB
> +	   does not distinguish between quiet and signalling NaNs).  */
> +	if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
> +	  set_gdbarch_long_double_format (gdbarch, &floatformat_ia64_quad_big);
> +	else
> +	  set_gdbarch_long_double_format (gdbarch, &floatformat_ia64_quad_little);
>  	tramp_frame_prepend_unwinder (gdbarch, &mips_linux_n32_rt_sigframe);
>  	break;
>        case MIPS_ABI_N64:
> @@ -1118,6 +1128,15 @@ mips_linux_init_abi (struct gdbarch_info
>  	set_solib_svr4_fetch_link_map_offsets
>  	  (gdbarch, svr4_lp64_fetch_link_map_offsets);
>  	set_mips_linux_register_addr (gdbarch, mips64_linux_register_addr);
> +	set_gdbarch_long_double_bit (gdbarch, 128);
> +	/* These floatformats should probably be renamed.  MIPS uses
> +	   the same 128-bit IEEE floating point format that IA-64 uses,
> +	   except that the quiet/signalling NaN bit is reversed (GDB
> +	   does not distinguish between quiet and signalling NaNs).  */
> +	if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
> +	  set_gdbarch_long_double_format (gdbarch, &floatformat_ia64_quad_big);
> +	else
> +	  set_gdbarch_long_double_format (gdbarch, &floatformat_ia64_quad_little);
>  	tramp_frame_prepend_unwinder (gdbarch, &mips_linux_n64_rt_sigframe);
>  	break;
>        default:
> Index: src/gdb/mips-tdep.c
> ===================================================================
> --- src.orig/gdb/mips-tdep.c	2006-03-14 15:44:19.000000000 -0500
> +++ src/gdb/mips-tdep.c	2006-03-14 17:05:07.000000000 -0500
> @@ -1,7 +1,7 @@
>  /* Target-dependent code for the MIPS architecture, for GDB, the GNU Debugger.
>  
>     Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
> -   1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
> +   1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
>     Free Software Foundation, Inc.
>  
>     Contributed by Alessandro Forin(af@cs.cmu.edu) at CMU
> @@ -2911,6 +2911,24 @@ mips_n32n64_return_value (struct gdbarch
>        || TYPE_LENGTH (type) > 2 * mips_abi_regsize (gdbarch))
>      return RETURN_VALUE_STRUCT_CONVENTION;
>    else if (TYPE_CODE (type) == TYPE_CODE_FLT
> +	   && TYPE_LENGTH (type) == 16
> +	   && tdep->mips_fpu_type != MIPS_FPU_NONE)
> +    {
> +      /* A 128-bit floating-point value fills both $f0 and $f2.  The
> +	 two registers are used in the same as memory order, so the
> +	 eight bytes with the lower memory address are in $f0.  */
> +      if (mips_debug)
> +	fprintf_unfiltered (gdb_stderr, "Return float in $f0 and $f2\n");
> +      mips_xfer_register (regcache,
> +			  NUM_REGS + mips_regnum (current_gdbarch)->fp0,
> +			  8, TARGET_BYTE_ORDER, readbuf, writebuf, 0);
> +      mips_xfer_register (regcache,
> +			  NUM_REGS + mips_regnum (current_gdbarch)->fp0 + 2,
> +			  8, TARGET_BYTE_ORDER, readbuf ? readbuf + 8 : readbuf,
> +			  writebuf ? writebuf + 8 : writebuf, 0);
> +      return RETURN_VALUE_REGISTER_CONVENTION;
> +    }
> +  else if (TYPE_CODE (type) == TYPE_CODE_FLT
>  	   && tdep->mips_fpu_type != MIPS_FPU_NONE)
>      {
>        /* A floating-point value belongs in the least significant part
> @@ -4037,7 +4055,6 @@ print_gp_register_row (struct ui_file *f
>    int regnum;
>  
>    /* For GP registers, we print a separate row of names above the vals */
> -  fprintf_filtered (file, "     ");
>    for (col = 0, regnum = start_regnum;
>         col < ncols && regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++)
>      {
> @@ -4046,11 +4063,17 @@ print_gp_register_row (struct ui_file *f
>        if (TYPE_CODE (gdbarch_register_type (gdbarch, regnum)) ==
>  	  TYPE_CODE_FLT)
>  	break;			/* end the row: reached FP register */
> +      if (col == 0)
> +	fprintf_filtered (file, "     ");
>        fprintf_filtered (file,
>  			mips_abi_regsize (current_gdbarch) == 8 ? "%17s" : "%9s",
>  			REGISTER_NAME (regnum));
>        col++;
>      }
> +
> +  if (col == 0)
> +    return regnum;
> +
>    /* print the R0 to R31 names */
>    if ((start_regnum % NUM_REGS) < MIPS_NUMREGS)
>      fprintf_filtered (file, "\n R%-4d", start_regnum % NUM_REGS);
> Index: src/gdb/Makefile.in
> ===================================================================
> --- src.orig/gdb/Makefile.in	2006-03-14 15:47:19.000000000 -0500
> +++ src/gdb/Makefile.in	2006-03-14 17:06:11.000000000 -0500
> @@ -2299,7 +2299,7 @@ mips-linux-nat.o: mips-linux-nat.c $(def
>  mips-linux-tdep.o: mips-linux-tdep.c $(defs_h) $(gdbcore_h) $(target_h) \
>  	$(solib_svr4_h) $(osabi_h) $(mips_tdep_h) $(gdb_string_h) \
>  	$(gdb_assert_h) $(frame_h) $(regcache_h) $(trad_frame_h) \
> -	$(tramp_frame_h)
> +	$(tramp_frame_h) $(floatformat_h)
>  mips-mdebug-tdep.o: mips-mdebug-tdep.c $(defs_h) $(frame_h) $(mips_tdep_h) \
>  	$(trad_frame_h) $(block_h) $(symtab_h) $(objfiles_h) $(elf_mips_h) \
>  	$(elf_bfd_h) $(gdb_assert_h) $(frame_unwind_h) $(frame_base_h) \
>