[RFA/mips] Fix crash trying to print long double float

[Joel Brobecker]

> >Tested on mips-irix. OK to apply?
> 
> Yes, with these tweaks, commit:

Thanks. Here is what I just checked in:

2004-08-08  Joel Brobecker  <brobecker@gnat.com>

        * mips-tdep.c: Include "floatformat.h".
        (n32n64_floatformat_always_valid): New function.
        (floatformat_n32n64_long_double_big): New constant.
        (mips_gdbarch_init): Set size and format of long double
        for N32 and N64 ABIs.
        * Makefile.in (mips-tdep.o): Update dependencies.

-- 
Joel
-------------- next part --------------
Index: mips-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/mips-tdep.c,v
retrieving revision 1.309
diff -u -p -r1.309 mips-tdep.c
--- mips-tdep.c	3 Aug 2004 01:12:43 -0000	1.309
+++ mips-tdep.c	8 Aug 2004 17:26:15 -0000
@@ -54,6 +54,7 @@
 #include "frame-base.h"
 #include "trad-frame.h"
 #include "infcall.h"
+#include "floatformat.h"
 
 static const struct objfile_data *mips_pdr_data;
 
@@ -149,6 +150,32 @@ struct gdbarch_tdep
   const char **mips_processor_reg_names;
 };
 
+static int
+n32n64_floatformat_always_valid (const struct floatformat *fmt,
+                                 const char *from)
+{
+  return 1;
+}
+
+/* FIXME: brobecker/2004-08-08: Long Double values are 128 bit long.
+   They are implemented as a pair of 64bit doubles where the high
+   part holds the result of the operation rounded to double, and
+   the low double holds the difference between the exact result and
+   the rounded result.  So "high" + "low" contains the result with
+   added precision.  Unfortunately, the floatformat structure used
+   by GDB is not powerful enough to describe this format.  As a temporary
+   measure, we define a 128bit floatformat that only uses the high part.
+   We lose a bit of precision but that's probably the best we can do
+   for now with the current infrastructure.  */
+
+static const struct floatformat floatformat_n32n64_long_double_big =
+{
+  floatformat_big, 128, 0, 1, 11, 1023, 2047, 12, 52,
+  floatformat_intbit_no,
+  "floatformat_ieee_double_big",
+  n32n64_floatformat_always_valid
+};
+
 const struct mips_regnum *
 mips_regnum (struct gdbarch *gdbarch)
 {
@@ -6323,6 +6350,9 @@ mips_gdbarch_init (struct gdbarch_info i
       set_gdbarch_long_bit (gdbarch, 32);
       set_gdbarch_ptr_bit (gdbarch, 32);
       set_gdbarch_long_long_bit (gdbarch, 64);
+      set_gdbarch_long_double_bit (gdbarch, 128);
+      set_gdbarch_long_double_format (gdbarch,
+                                      &floatformat_n32n64_long_double_big);
       break;
     case MIPS_ABI_N64:
       set_gdbarch_push_dummy_call (gdbarch, mips_n32n64_push_dummy_call);
@@ -6333,6 +6363,9 @@ mips_gdbarch_init (struct gdbarch_info i
       set_gdbarch_long_bit (gdbarch, 64);
       set_gdbarch_ptr_bit (gdbarch, 64);
       set_gdbarch_long_long_bit (gdbarch, 64);
+      set_gdbarch_long_double_bit (gdbarch, 128);
+      set_gdbarch_long_double_format (gdbarch,
+                                      &floatformat_n32n64_long_double_big);
       break;
     default:
       internal_error (__FILE__, __LINE__, "unknown ABI in switch");
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.606
diff -u -p -r1.606 Makefile.in
--- Makefile.in	6 Aug 2004 19:14:44 -0000	1.606
+++ Makefile.in	8 Aug 2004 17:26:16 -0000
@@ -2206,7 +2206,8 @@ mips-tdep.o: mips-tdep.c $(defs_h) $(gdb
 	$(target_h) $(arch_utils_h) $(regcache_h) $(osabi_h) $(mips_tdep_h) \
 	$(block_h) $(reggroups_h) $(opcode_mips_h) $(elf_mips_h) \
 	$(elf_bfd_h) $(symcat_h) $(sim_regno_h) $(dis_asm_h) \
-	$(frame_unwind_h) $(frame_base_h) $(trad_frame_h) $(infcall_h)
+	$(frame_unwind_h) $(frame_base_h) $(trad_frame_h) $(infcall_h) \
+	$(floatformat_h)
 mipsv4-nat.o: mipsv4-nat.c $(defs_h) $(inferior_h) $(gdbcore_h) $(target_h) \
 	$(regcache_h) $(gregset_h)
 mn10300-tdep.o: mn10300-tdep.c $(defs_h) $(frame_h) $(inferior_h) \