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, 11 insertions, 3 deletions

diff --git a/gdb/value.c b/gdb/value.c
index 88ba18e4dda..bc211139f77 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -2922,10 +2922,8 @@ unpack_long (struct type *type, const gdb_byte *valaddr)
 	return extract_signed_integer (valaddr, len, byte_order);
 
     case TYPE_CODE_FLT:
-      return (LONGEST) extract_typed_floating (valaddr, type);
-
     case TYPE_CODE_DECFLOAT:
-      return decimal_to_longest (valaddr, len, byte_order);
+      return target_float_to_longest (valaddr, type);
 
     case TYPE_CODE_PTR:
     case TYPE_CODE_REF:
@@ -3539,6 +3537,11 @@ pack_long (gdb_byte *buf, struct type *type, LONGEST num)
       store_typed_address (buf, type, (CORE_ADDR) num);
       break;
 
+    case TYPE_CODE_FLT:
+    case TYPE_CODE_DECFLOAT:
+      target_float_from_longest (buf, type, num);
+      break;
+
     default:
       error (_("Unexpected type (%d) encountered for integer constant."),
 	     TYPE_CODE (type));
@@ -3576,6 +3579,11 @@ pack_unsigned_long (gdb_byte *buf, struct type *type, ULONGEST num)
       store_typed_address (buf, type, (CORE_ADDR) num);
       break;
 
+    case TYPE_CODE_FLT:
+    case TYPE_CODE_DECFLOAT:
+      target_float_from_ulongest (buf, type, num);
+      break;
+
     default:
       error (_("Unexpected type (%d) encountered "
 	       "for unsigned integer constant."),