+/* Return nonzero if a value of type TYPE stored in register REGNUM
+ needs any special handling. */
+
+static int
+m68k_convert_register_p (int regnum, struct type *type)
+{
+ return (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FP0_REGNUM + 7);
+}
+
+/* Read a value of type TYPE from register REGNUM in frame FRAME, and
+ return its contents in TO. */
+
+static void
+m68k_register_to_value (struct frame_info *frame, int regnum,
+ struct type *type, void *to)
+{
+ char from[M68K_MAX_REGISTER_SIZE];
+
+ /* We only support floating-point values. */
+ if (TYPE_CODE (type) != TYPE_CODE_FLT)
+ {
+ warning ("Cannot convert floating-point register value "
+ "to non-floating-point type.");
+ return;
+ }
+
+ /* Convert to TYPE. This should be a no-op if TYPE is equivalent to
+ the extended floating-point format used by the FPU. */
+ get_frame_register (frame, regnum, from);
+ convert_typed_floating (from, builtin_type_m68881_ext, to, type);
+}
+
+/* Write the contents FROM of a value of type TYPE into register
+ REGNUM in frame FRAME. */
+
+static void
+m68k_value_to_register (struct frame_info *frame, int regnum,
+ struct type *type, const void *from)
+{
+ char to[M68K_MAX_REGISTER_SIZE];
+
+ /* We only support floating-point values. */
+ if (TYPE_CODE (type) != TYPE_CODE_FLT)
+ {
+ warning ("Cannot convert non-floating-point type "
+ "to floating-point register value.");
+ return;
+ }
+
+ /* Convert from TYPE. This should be a no-op if TYPE is equivalent
+ to the extended floating-point format used by the FPU. */
+ convert_typed_floating (from, type, to, builtin_type_m68881_ext);
+ put_frame_register (frame, regnum, to);
+}
+
+\f
+/* There is a fair number of calling conventions that are in somewhat
+ wide use. The 68000/08/10 don't support an FPU, not even as a
+ coprocessor. All function return values are stored in %d0/%d1.
+ Structures are returned in a static buffer, a pointer to which is
+ returned in %d0. This means that functions returning a structure
+ are not re-entrant. To avoid this problem some systems use a
+ convention where the caller passes a pointer to a buffer in %a1
+ where the return values is to be stored. This convention is the
+ default, and is implemented in the function m68k_return_value.
+
+ The 68020/030/040/060 do support an FPU, either as a coprocessor
+ (68881/2) or built-in (68040/68060). That's why System V release 4
+ (SVR4) instroduces a new calling convention specified by the SVR4
+ psABI. Integer values are returned in %d0/%d1, pointer return
+ values in %a0 and floating values in %fp0. When calling functions
+ returning a structure the caller should pass a pointer to a buffer
+ for the return value in %a0. This convention is implemented in the
+ function m68k_svr4_return_value, and by appropriately setting the
+ struct_value_regnum member of `struct gdbarch_tdep'.
+
+ GNU/Linux returns values in the same way as SVR4 does, but uses %a1
+ for passing the structure return value buffer.
+
+ GCC can also generate code where small structures are returned in
+ %d0/%d1 instead of in memory by using -freg-struct-return. This is
+ the default on NetBSD a.out, OpenBSD and GNU/Linux and several
+ embedded systems. This convention is implemented by setting the
+ struct_return member of `struct gdbarch_tdep' to reg_struct_return. */
+
+/* Read a function return value of TYPE from REGCACHE, and copy that