Target FP: Add conversion routines to target-float.{c,h}

This patch adds the following conversion routines:
 - target_float_to_longest
 - target_float_from_longest
 - target_float_from_ulongest
 - target_float_convert
which call the equivalent decimal_ routines to handle decimal FP,
and call helper routines that currently still go via DOUBLEST to
handle binary FP.

The target_float_convert routine not only handles BFP<->BFP and
DFP<->DFP conversions, but also BFP<->DFP, which are implemented
by converting to a string and back.

These helpers are used in particular to implement conversion
from and to FP in value_cast, without going through DOUBLEST there.
In order to implement this for the FP<-integer case, the
pack_long / pack_unsigned_long routines are extended to support
floating-point values as output (thereby allowing use of
value_from_[u]longest with a floating-point target type).

This latter change also allows simplification of value_one.

gdb/ChangeLog:
2017-11-06  Ulrich Weigand  <uweigand@de.ibm.com>

	* target-float.c (floatformat_to_longest): New function.
	(floatformat_from_longest, floatformat_from_ulongest): Likewise.
	(floatformat_convert): Likewise.
	(target_float_to_longest): Likewise.
	(target_float_from_longest, target_float_from_ulongest): Likewise.
	(target_float_convert): Likewise.
	* target-float.h (target_float_to_longest): Add prototype.
	(target_float_from_longest, target_float_from_ulongest): Likewise.
	(target_float_convert): Likewise.

	* value.c (unpack_long): Use target_float_to_longest.
	(pack_long): Allow FP types.  Use target_float_from_longest.
	(pack_unsigned_long): Likewise using target_float_from_ulongest.
	* valops.c: Include "target-float.h".  Do not include "dfp.h".
	(value_cast): Handle conversions to FP using target_float_convert,
	value_from_ulongest, and value_from_longest.
	(value_one): Use value_from_longest for FP types as well.

1 files changed, 13 insertions, 33 deletions

diff --git a/gdb/valops.c b/gdb/valops.c
index de4544c..ccc2bc2 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -34,7 +34,7 @@
 #include "infcall.h"
 #include "dictionary.h"
 #include "cp-support.h"
-#include "dfp.h"
+#include "target-float.h"
 #include "tracepoint.h"
 #include "observer.h"
 #include "objfiles.h"
@@ -462,29 +462,21 @@ value_cast (struct type *type, struct value *arg2)
 	return v;
     }
 
-  if (code1 == TYPE_CODE_FLT && scalar)
-    return value_from_double (to_type, value_as_double (arg2));
-  else if (code1 == TYPE_CODE_DECFLOAT && scalar)
+  if (is_floating_type (type) && scalar)
     {
-      enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
-      int dec_len = TYPE_LENGTH (type);
-      gdb_byte dec[16];
+      if (is_floating_value (arg2))
+	{
+	  struct value *v = allocate_value (to_type);
+	  target_float_convert (value_contents (arg2), type2,
+				value_contents_raw (v), type);
+	  return v;
+	}
 
-      if (code2 == TYPE_CODE_FLT)
-	decimal_from_doublest (value_as_double (arg2),
-			       dec, dec_len, byte_order);
-      else if (code2 == TYPE_CODE_DECFLOAT)
-	decimal_convert (value_contents (arg2), TYPE_LENGTH (type2),
-			 byte_order, dec, dec_len, byte_order);
       /* The only option left is an integral type.  */
-      else if (TYPE_UNSIGNED (type2))
-	decimal_from_ulongest (value_as_long (arg2),
-			       dec, dec_len, byte_order);
+      if (TYPE_UNSIGNED (type2))
+	return value_from_ulongest (to_type, value_as_long (arg2));
       else
-	decimal_from_longest (value_as_long (arg2),
-			      dec, dec_len, byte_order);
-
-      return value_from_decfloat (to_type, dec);
+	return value_from_longest (to_type, value_as_long (arg2));
     }
   else if ((code1 == TYPE_CODE_INT || code1 == TYPE_CODE_ENUM
 	    || code1 == TYPE_CODE_RANGE)
@@ -868,19 +860,7 @@ value_one (struct type *type)
   struct type *type1 = check_typedef (type);
   struct value *val;
 
-  if (TYPE_CODE (type1) == TYPE_CODE_DECFLOAT)
-    {
-      enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
-      gdb_byte v[16];
-
-      decimal_from_string (v, TYPE_LENGTH (type), byte_order, "1");
-      val = value_from_decfloat (type, v);
-    }
-  else if (TYPE_CODE (type1) == TYPE_CODE_FLT)
-    {
-      val = value_from_double (type, (DOUBLEST) 1);
-    }
-  else if (is_integral_type (type1))
+  if (is_integral_type (type1) || is_floating_type (type1))
     {
       val = value_from_longest (type, (LONGEST) 1);
     }