[deliverable/binutils-gdb.git] / gdb / rs6000-lynx178-tdep.c

/* Copyright (C) 2012 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "osabi.h"
#include "regcache.h"
#include "gdbcore.h"
#include "gdbtypes.h"
#include "infcall.h"
#include "ppc-tdep.h"
#include "value.h"
#include "xcoffread.h"

/* Implement the "push_dummy_call" gdbarch method.  */

static CORE_ADDR
rs6000_lynx178_push_dummy_call (struct gdbarch *gdbarch,
				struct value *function,
				struct regcache *regcache, CORE_ADDR bp_addr,
				int nargs, struct value **args, CORE_ADDR sp,
				int struct_return, CORE_ADDR struct_addr)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  int ii;
  int len = 0;
  int argno;			/* current argument number */
  int argbytes;			/* current argument byte */
  gdb_byte tmp_buffer[50];
  int f_argno = 0;		/* current floating point argno */
  int wordsize = gdbarch_tdep (gdbarch)->wordsize;
  CORE_ADDR func_addr = find_function_addr (function, NULL);

  struct value *arg = 0;
  struct type *type;

  ULONGEST saved_sp;

  /* The calling convention this function implements assumes the
     processor has floating-point registers.  We shouldn't be using it
     on PPC variants that lack them.  */
  gdb_assert (ppc_floating_point_unit_p (gdbarch));

  /* The first eight words of ther arguments are passed in registers.
     Copy them appropriately.  */
  ii = 0;

  /* If the function is returning a `struct', then the first word
     (which will be passed in r3) is used for struct return address.
     In that case we should advance one word and start from r4
     register to copy parameters.  */
  if (struct_return)
    {
      regcache_raw_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
				   struct_addr);
      ii++;
    }

  /* Effectively indirect call... gcc does...

     return_val example( float, int);

     eabi:
     float in fp0, int in r3
     offset of stack on overflow 8/16
     for varargs, must go by type.
     power open:
     float in r3&r4, int in r5
     offset of stack on overflow different
     both:
     return in r3 or f0.  If no float, must study how gcc emulates floats;
     pay attention to arg promotion.
     User may have to cast\args to handle promotion correctly
     since gdb won't know if prototype supplied or not.  */

  for (argno = 0, argbytes = 0; argno < nargs && ii < 8; ++ii)
    {
      int reg_size = register_size (gdbarch, ii + 3);

      arg = args[argno];
      type = check_typedef (value_type (arg));
      len = TYPE_LENGTH (type);

      if (TYPE_CODE (type) == TYPE_CODE_FLT)
	{

	  /* Floating point arguments are passed in fpr's, as well as gpr's.
	     There are 13 fpr's reserved for passing parameters.  At this point
	     there is no way we would run out of them.  */

	  gdb_assert (len <= 8);

	  regcache_cooked_write (regcache,
	                         tdep->ppc_fp0_regnum + 1 + f_argno,
	                         value_contents (arg));
	  ++f_argno;
	}

      if (len > reg_size)
	{

	  /* Argument takes more than one register.  */
	  while (argbytes < len)
	    {
	      gdb_byte word[MAX_REGISTER_SIZE];
	      memset (word, 0, reg_size);
	      memcpy (word,
		      ((char *) value_contents (arg)) + argbytes,
		      (len - argbytes) > reg_size
		        ? reg_size : len - argbytes);
	      regcache_cooked_write (regcache,
	                            tdep->ppc_gp0_regnum + 3 + ii,
				    word);
	      ++ii, argbytes += reg_size;

	      if (ii >= 8)
		goto ran_out_of_registers_for_arguments;
	    }
	  argbytes = 0;
	  --ii;
	}
      else
	{
	  /* Argument can fit in one register.  No problem.  */
	  int adj = gdbarch_byte_order (gdbarch)
		    == BFD_ENDIAN_BIG ? reg_size - len : 0;
	  gdb_byte word[MAX_REGISTER_SIZE];

	  memset (word, 0, reg_size);
	  memcpy (word, value_contents (arg), len);
	  regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3 +ii, word);
	}
      ++argno;
    }

ran_out_of_registers_for_arguments:

  regcache_cooked_read_unsigned (regcache,
				 gdbarch_sp_regnum (gdbarch),
				 &saved_sp);

  /* Location for 8 parameters are always reserved.  */
  sp -= wordsize * 8;

  /* Another six words for back chain, TOC register, link register, etc.  */
  sp -= wordsize * 6;

  /* Stack pointer must be quadword aligned.  */
  sp = align_down (sp, 16);

  /* If there are more arguments, allocate space for them in
     the stack, then push them starting from the ninth one.  */

  if ((argno < nargs) || argbytes)
    {
      int space = 0, jj;

      if (argbytes)
	{
	  space += align_up (len - argbytes, 4);
	  jj = argno + 1;
	}
      else
	jj = argno;

      for (; jj < nargs; ++jj)
	{
	  struct value *val = args[jj];

	  space += align_up (TYPE_LENGTH (value_type (val)), 4);
	}

      /* Add location required for the rest of the parameters.  */
      space = align_up (space, 16);
      sp -= space;

      /* This is another instance we need to be concerned about
         securing our stack space.  If we write anything underneath %sp
         (r1), we might conflict with the kernel who thinks he is free
         to use this area.  So, update %sp first before doing anything
         else.  */

      regcache_raw_write_signed (regcache,
				 gdbarch_sp_regnum (gdbarch), sp);

      /* If the last argument copied into the registers didn't fit there
         completely, push the rest of it into stack.  */

      if (argbytes)
	{
	  write_memory (sp + 24 + (ii * 4),
			value_contents (arg) + argbytes,
			len - argbytes);
	  ++argno;
	  ii += align_up (len - argbytes, 4) / 4;
	}

      /* Push the rest of the arguments into stack.  */
      for (; argno < nargs; ++argno)
	{

	  arg = args[argno];
	  type = check_typedef (value_type (arg));
	  len = TYPE_LENGTH (type);


	  /* Float types should be passed in fpr's, as well as in the
             stack.  */
	  if (TYPE_CODE (type) == TYPE_CODE_FLT && f_argno < 13)
	    {

	      gdb_assert (len <= 8);

	      regcache_cooked_write (regcache,
				     tdep->ppc_fp0_regnum + 1 + f_argno,
				     value_contents (arg));
	      ++f_argno;
	    }

	  write_memory (sp + 24 + (ii * 4), value_contents (arg), len);
	  ii += align_up (len, 4) / 4;
	}
    }

  /* Set the stack pointer.  According to the ABI, the SP is meant to
     be set _before_ the corresponding stack space is used.  On AIX,
     this even applies when the target has been completely stopped!
     Not doing this can lead to conflicts with the kernel which thinks
     that it still has control over this not-yet-allocated stack
     region.  */
  regcache_raw_write_signed (regcache, gdbarch_sp_regnum (gdbarch), sp);

  /* Set back chain properly.  */
  store_unsigned_integer (tmp_buffer, wordsize, byte_order, saved_sp);
  write_memory (sp, tmp_buffer, wordsize);

  /* Point the inferior function call's return address at the dummy's
     breakpoint.  */
  regcache_raw_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr);

  target_store_registers (regcache, -1);
  return sp;
}

/* Implement the "return_value" gdbarch method.  */

static enum return_value_convention
rs6000_lynx178_return_value (struct gdbarch *gdbarch, struct value *function,
			     struct type *valtype, struct regcache *regcache,
			     gdb_byte *readbuf, const gdb_byte *writebuf)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  /* The calling convention this function implements assumes the
     processor has floating-point registers.  We shouldn't be using it
     on PowerPC variants that lack them.  */
  gdb_assert (ppc_floating_point_unit_p (gdbarch));

  /* AltiVec extension: Functions that declare a vector data type as a
     return value place that return value in VR2.  */
  if (TYPE_CODE (valtype) == TYPE_CODE_ARRAY && TYPE_VECTOR (valtype)
      && TYPE_LENGTH (valtype) == 16)
    {
      if (readbuf)
	regcache_cooked_read (regcache, tdep->ppc_vr0_regnum + 2, readbuf);
      if (writebuf)
	regcache_cooked_write (regcache, tdep->ppc_vr0_regnum + 2, writebuf);

      return RETURN_VALUE_REGISTER_CONVENTION;
    }

  /* If the called subprogram returns an aggregate, there exists an
     implicit first argument, whose value is the address of a caller-
     allocated buffer into which the callee is assumed to store its
     return value.  All explicit parameters are appropriately
     relabeled.  */
  if (TYPE_CODE (valtype) == TYPE_CODE_STRUCT
      || TYPE_CODE (valtype) == TYPE_CODE_UNION
      || TYPE_CODE (valtype) == TYPE_CODE_ARRAY)
    return RETURN_VALUE_STRUCT_CONVENTION;

  /* Scalar floating-point values are returned in FPR1 for float or
     double, and in FPR1:FPR2 for quadword precision.  Fortran
     complex*8 and complex*16 are returned in FPR1:FPR2, and
     complex*32 is returned in FPR1:FPR4.  */
  if (TYPE_CODE (valtype) == TYPE_CODE_FLT
      && (TYPE_LENGTH (valtype) == 4 || TYPE_LENGTH (valtype) == 8))
    {
      struct type *regtype = register_type (gdbarch, tdep->ppc_fp0_regnum);
      gdb_byte regval[8];

      /* FIXME: kettenis/2007-01-01: Add support for quadword
	 precision and complex.  */

      if (readbuf)
	{
	  regcache_cooked_read (regcache, tdep->ppc_fp0_regnum + 1, regval);
	  convert_typed_floating (regval, regtype, readbuf, valtype);
	}
      if (writebuf)
	{
	  convert_typed_floating (writebuf, valtype, regval, regtype);
	  regcache_cooked_write (regcache, tdep->ppc_fp0_regnum + 1, regval);
	}

      return RETURN_VALUE_REGISTER_CONVENTION;
  }

  /* Values of the types int, long, short, pointer, and char (length
     is less than or equal to four bytes), as well as bit values of
     lengths less than or equal to 32 bits, must be returned right
     justified in GPR3 with signed values sign extended and unsigned
     values zero extended, as necessary.  */
  if (TYPE_LENGTH (valtype) <= tdep->wordsize)
    {
      if (readbuf)
	{
	  ULONGEST regval;

	  /* For reading we don't have to worry about sign extension.  */
	  regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
					 &regval);
	  store_unsigned_integer (readbuf, TYPE_LENGTH (valtype), byte_order,
				  regval);
	}
      if (writebuf)
	{
	  /* For writing, use unpack_long since that should handle any
	     required sign extension.  */
	  regcache_cooked_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
					  unpack_long (valtype, writebuf));
	}

      return RETURN_VALUE_REGISTER_CONVENTION;
    }

  /* Eight-byte non-floating-point scalar values must be returned in
     GPR3:GPR4.  */

  if (TYPE_LENGTH (valtype) == 8)
    {
      gdb_assert (TYPE_CODE (valtype) != TYPE_CODE_FLT);
      gdb_assert (tdep->wordsize == 4);

      if (readbuf)
	{
	  gdb_byte regval[8];

	  regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 3, regval);
	  regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 4,
				regval + 4);
	  memcpy (readbuf, regval, 8);
	}
      if (writebuf)
	{
	  regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3, writebuf);
	  regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 4,
				 writebuf + 4);
	}

      return RETURN_VALUE_REGISTER_CONVENTION;
    }

  return RETURN_VALUE_STRUCT_CONVENTION;
}

/* PowerPC Lynx178 OSABI sniffer.  */

static enum gdb_osabi
rs6000_lynx178_osabi_sniffer (bfd *abfd)
{
  if (bfd_get_flavour (abfd) != bfd_target_xcoff_flavour)
    return GDB_OSABI_UNKNOWN;

  /* The only noticeable difference between Lynx178 XCOFF files and
     AIX XCOFF files comes from the fact that there are no shared
     libraries on Lynx178.  So if the number of import files is
     different from zero, it cannot be a Lynx178 binary.  */
  if (xcoff_get_n_import_files (abfd) != 0)
    return GDB_OSABI_UNKNOWN;

  return GDB_OSABI_LYNXOS178;
}

/* Callback for powerpc-lynx178 initialization.  */

static void
rs6000_lynx178_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  set_gdbarch_push_dummy_call (gdbarch, rs6000_lynx178_push_dummy_call);
  set_gdbarch_return_value (gdbarch, rs6000_lynx178_return_value);
  set_gdbarch_long_double_bit (gdbarch, 8 * TARGET_CHAR_BIT);
}

/* -Wmissing-prototypes.  */
extern initialize_file_ftype _initialize_rs6000_lynx178_tdep;

void
_initialize_rs6000_lynx178_tdep (void)
{
  gdbarch_register_osabi_sniffer (bfd_arch_rs6000,
                                  bfd_target_xcoff_flavour,
                                  rs6000_lynx178_osabi_sniffer);
  gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_LYNXOS178,
                          rs6000_lynx178_init_osabi);
}
Commit	Line	Data
d5367fe1 JB	1	/* Copyright (C) 2012 Free Software Foundation, Inc.
	2
	3	This file is part of GDB.
	4
	5	This program is free software; you can redistribute it and/or modify
	6	it under the terms of the GNU General Public License as published by
	7	the Free Software Foundation; either version 3 of the License, or
	8	(at your option) any later version.
	9
	10	This program is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	GNU General Public License for more details.
	14
	15	You should have received a copy of the GNU General Public License
	16	along with this program. If not, see <http://www.gnu.org/licenses/>. */
	17
	18	#include "defs.h"
	19	#include "osabi.h"
	20	#include "regcache.h"
	21	#include "gdbcore.h"
	22	#include "gdbtypes.h"
	23	#include "infcall.h"
	24	#include "ppc-tdep.h"
	25	#include "value.h"
	26	#include "xcoffread.h"
	27
	28	/* Implement the "push_dummy_call" gdbarch method. */
	29
	30	static CORE_ADDR
	31	rs6000_lynx178_push_dummy_call (struct gdbarch *gdbarch,
	32	struct value *function,
	33	struct regcache *regcache, CORE_ADDR bp_addr,
	34	int nargs, struct value **args, CORE_ADDR sp,
	35	int struct_return, CORE_ADDR struct_addr)
	36	{
	37	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
	38	enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
	39	int ii;
	40	int len = 0;
	41	int argno; /* current argument number */
	42	int argbytes; /* current argument byte */
	43	gdb_byte tmp_buffer[50];
	44	int f_argno = 0; /* current floating point argno */
	45	int wordsize = gdbarch_tdep (gdbarch)->wordsize;
	46	CORE_ADDR func_addr = find_function_addr (function, NULL);
	47
	48	struct value *arg = 0;
	49	struct type *type;
	50
	51	ULONGEST saved_sp;
	52
	53	/* The calling convention this function implements assumes the
	54	processor has floating-point registers. We shouldn't be using it
	55	on PPC variants that lack them. */
	56	gdb_assert (ppc_floating_point_unit_p (gdbarch));
	57
	58	/* The first eight words of ther arguments are passed in registers.
	59	Copy them appropriately. */
	60	ii = 0;
	61
	62	/* If the function is returning a `struct', then the first word
	63	(which will be passed in r3) is used for struct return address.
	64	In that case we should advance one word and start from r4
65	register to copy parameters. */
66	if (struct_return)
67	{
68	regcache_raw_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
69	struct_addr);
70	ii++;
71	}
72
73	/* Effectively indirect call... gcc does...
74
75	return_val example( float, int);
76
77	eabi:
78	float in fp0, int in r3
79	offset of stack on overflow 8/16
80	for varargs, must go by type.
81	power open:
82	float in r3&r4, int in r5
83	offset of stack on overflow different
84	both:
85	return in r3 or f0. If no float, must study how gcc emulates floats;
86	pay attention to arg promotion.
87	User may have to cast\args to handle promotion correctly
88	since gdb won't know if prototype supplied or not. */
89
90	for (argno = 0, argbytes = 0; argno < nargs && ii < 8; ++ii)
91	{
92	int reg_size = register_size (gdbarch, ii + 3);
93
94	arg = args[argno];
95	type = check_typedef (value_type (arg));
96	len = TYPE_LENGTH (type);
97
98	if (TYPE_CODE (type) == TYPE_CODE_FLT)
99	{
100
101	/* Floating point arguments are passed in fpr's, as well as gpr's.
102	There are 13 fpr's reserved for passing parameters. At this point
103	there is no way we would run out of them. */
104
105	gdb_assert (len <= 8);
106
107	regcache_cooked_write (regcache,
108	tdep->ppc_fp0_regnum + 1 + f_argno,
109	value_contents (arg));
110	++f_argno;
111	}
112
113	if (len > reg_size)
114	{
115
116	/* Argument takes more than one register. */
117	while (argbytes < len)
118	{
119	gdb_byte word[MAX_REGISTER_SIZE];
120	memset (word, 0, reg_size);
121	memcpy (word,
122	((char *) value_contents (arg)) + argbytes,
123	(len - argbytes) > reg_size
124	? reg_size : len - argbytes);
125	regcache_cooked_write (regcache,
126	tdep->ppc_gp0_regnum + 3 + ii,
127	word);
128	++ii, argbytes += reg_size;
129
130	if (ii >= 8)
131	goto ran_out_of_registers_for_arguments;
132	}
133	argbytes = 0;
134	--ii;
135	}
136	else
137	{
138	/* Argument can fit in one register. No problem. */
139	int adj = gdbarch_byte_order (gdbarch)
140	== BFD_ENDIAN_BIG ? reg_size - len : 0;
141	gdb_byte word[MAX_REGISTER_SIZE];
142
143	memset (word, 0, reg_size);
144	memcpy (word, value_contents (arg), len);
145	regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3 +ii, word);
146	}
147	++argno;
148	}
149
150	ran_out_of_registers_for_arguments:
151
152	regcache_cooked_read_unsigned (regcache,
153	gdbarch_sp_regnum (gdbarch),
154	&saved_sp);
155
156	/* Location for 8 parameters are always reserved. */
157	sp -= wordsize * 8;
158
159	/* Another six words for back chain, TOC register, link register, etc. */
160	sp -= wordsize * 6;
161
162	/* Stack pointer must be quadword aligned. */
163	sp = align_down (sp, 16);
164
165	/* If there are more arguments, allocate space for them in
166	the stack, then push them starting from the ninth one. */
167
168	if ((argno < nargs) \|\| argbytes)
169	{
170	int space = 0, jj;
171
172	if (argbytes)
173	{
174	space += align_up (len - argbytes, 4);
175	jj = argno + 1;
176	}
177	else
178	jj = argno;
179
180	for (; jj < nargs; ++jj)
181	{
182	struct value *val = args[jj];
183
184	space += align_up (TYPE_LENGTH (value_type (val)), 4);
185	}
186
187	/* Add location required for the rest of the parameters. */
188	space = align_up (space, 16);
189	sp -= space;
190
191	/* This is another instance we need to be concerned about
192	securing our stack space. If we write anything underneath %sp
193	(r1), we might conflict with the kernel who thinks he is free
194	to use this area. So, update %sp first before doing anything
195	else. */
196
197	regcache_raw_write_signed (regcache,
198	gdbarch_sp_regnum (gdbarch), sp);
199
200	/* If the last argument copied into the registers didn't fit there
201	completely, push the rest of it into stack. */
202
203	if (argbytes)
204	{
205	write_memory (sp + 24 + (ii * 4),
206	value_contents (arg) + argbytes,
207	len - argbytes);
208	++argno;
209	ii += align_up (len - argbytes, 4) / 4;
210	}
211
212	/* Push the rest of the arguments into stack. */
213	for (; argno < nargs; ++argno)
214	{
215
216	arg = args[argno];
217	type = check_typedef (value_type (arg));
218	len = TYPE_LENGTH (type);
219
220
221	/* Float types should be passed in fpr's, as well as in the
222	stack. */
223	if (TYPE_CODE (type) == TYPE_CODE_FLT && f_argno < 13)
224	{
225
226	gdb_assert (len <= 8);
227
228	regcache_cooked_write (regcache,
229	tdep->ppc_fp0_regnum + 1 + f_argno,
230	value_contents (arg));
231	++f_argno;
232	}
233
234	write_memory (sp + 24 + (ii * 4), value_contents (arg), len);
235	ii += align_up (len, 4) / 4;
236	}
237	}
238
239	/* Set the stack pointer. According to the ABI, the SP is meant to
240	be set _before_ the corresponding stack space is used. On AIX,
241	this even applies when the target has been completely stopped!
242	Not doing this can lead to conflicts with the kernel which thinks
243	that it still has control over this not-yet-allocated stack
244	region. */
245	regcache_raw_write_signed (regcache, gdbarch_sp_regnum (gdbarch), sp);
246
247	/* Set back chain properly. */
248	store_unsigned_integer (tmp_buffer, wordsize, byte_order, saved_sp);
249	write_memory (sp, tmp_buffer, wordsize);
250
251	/* Point the inferior function call's return address at the dummy's
252	breakpoint. */
253	regcache_raw_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr);
254
255	target_store_registers (regcache, -1);
256	return sp;
257	}
258
259	/* Implement the "return_value" gdbarch method. */
260
261	static enum return_value_convention
262	rs6000_lynx178_return_value (struct gdbarch gdbarch, struct value function,
263	struct type valtype, struct regcache regcache,
264	gdb_byte readbuf, const gdb_byte writebuf)
265	{
266	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
267	enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
268
269	/* The calling convention this function implements assumes the
270	processor has floating-point registers. We shouldn't be using it
271	on PowerPC variants that lack them. */
272	gdb_assert (ppc_floating_point_unit_p (gdbarch));
273
274	/* AltiVec extension: Functions that declare a vector data type as a
275	return value place that return value in VR2. */
276	if (TYPE_CODE (valtype) == TYPE_CODE_ARRAY && TYPE_VECTOR (valtype)
277	&& TYPE_LENGTH (valtype) == 16)
278	{
279	if (readbuf)
280	regcache_cooked_read (regcache, tdep->ppc_vr0_regnum + 2, readbuf);
281	if (writebuf)
282	regcache_cooked_write (regcache, tdep->ppc_vr0_regnum + 2, writebuf);
283
284	return RETURN_VALUE_REGISTER_CONVENTION;
285	}
286
287	/* If the called subprogram returns an aggregate, there exists an
288	implicit first argument, whose value is the address of a caller-
289	allocated buffer into which the callee is assumed to store its
290	return value. All explicit parameters are appropriately
291	relabeled. */
292	if (TYPE_CODE (valtype) == TYPE_CODE_STRUCT
293	\|\| TYPE_CODE (valtype) == TYPE_CODE_UNION
294	\|\| TYPE_CODE (valtype) == TYPE_CODE_ARRAY)
295	return RETURN_VALUE_STRUCT_CONVENTION;
296
297	/* Scalar floating-point values are returned in FPR1 for float or
298	double, and in FPR1:FPR2 for quadword precision. Fortran
299	complex8 and complex16 are returned in FPR1:FPR2, and
300	complex32 is returned in FPR1:FPR4. /
301	if (TYPE_CODE (valtype) == TYPE_CODE_FLT
302	&& (TYPE_LENGTH (valtype) == 4 \|\| TYPE_LENGTH (valtype) == 8))
303	{
304	struct type *regtype = register_type (gdbarch, tdep->ppc_fp0_regnum);
305	gdb_byte regval[8];
306
307	/* FIXME: kettenis/2007-01-01: Add support for quadword
308	precision and complex. */
309
310	if (readbuf)
311	{
312	regcache_cooked_read (regcache, tdep->ppc_fp0_regnum + 1, regval);
313	convert_typed_floating (regval, regtype, readbuf, valtype);
314	}
315	if (writebuf)
316	{
317	convert_typed_floating (writebuf, valtype, regval, regtype);
318	regcache_cooked_write (regcache, tdep->ppc_fp0_regnum + 1, regval);
319	}
320
321	return RETURN_VALUE_REGISTER_CONVENTION;
322	}
323
324	/* Values of the types int, long, short, pointer, and char (length
325	is less than or equal to four bytes), as well as bit values of
326	lengths less than or equal to 32 bits, must be returned right
327	justified in GPR3 with signed values sign extended and unsigned
328	values zero extended, as necessary. */
329	if (TYPE_LENGTH (valtype) <= tdep->wordsize)
330	{
331	if (readbuf)
332	{
333	ULONGEST regval;
334
335	/* For reading we don't have to worry about sign extension. */
336	regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
337	&regval);
338	store_unsigned_integer (readbuf, TYPE_LENGTH (valtype), byte_order,
339	regval);
340	}
341	if (writebuf)
342	{
343	/* For writing, use unpack_long since that should handle any
344	required sign extension. */
345	regcache_cooked_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
346	unpack_long (valtype, writebuf));
347	}
348
349	return RETURN_VALUE_REGISTER_CONVENTION;
350	}
351
352	/* Eight-byte non-floating-point scalar values must be returned in
353	GPR3:GPR4. */
354
355	if (TYPE_LENGTH (valtype) == 8)
356	{
357	gdb_assert (TYPE_CODE (valtype) != TYPE_CODE_FLT);
358	gdb_assert (tdep->wordsize == 4);
359
360	if (readbuf)
361	{
362	gdb_byte regval[8];
363
364	regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 3, regval);
365	regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 4,
366	regval + 4);
367	memcpy (readbuf, regval, 8);
368	}
369	if (writebuf)
370	{
371	regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3, writebuf);
372	regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 4,
373	writebuf + 4);
374	}
375
376	return RETURN_VALUE_REGISTER_CONVENTION;
377	}
378
379	return RETURN_VALUE_STRUCT_CONVENTION;
380	}
381
382	/* PowerPC Lynx178 OSABI sniffer. */
383
384	static enum gdb_osabi
385	rs6000_lynx178_osabi_sniffer (bfd *abfd)
386	{
387	if (bfd_get_flavour (abfd) != bfd_target_xcoff_flavour)
388	return GDB_OSABI_UNKNOWN;
389
390	/* The only noticeable difference between Lynx178 XCOFF files and
391	AIX XCOFF files comes from the fact that there are no shared
392	libraries on Lynx178. So if the number of import files is
393	different from zero, it cannot be a Lynx178 binary. */
394	if (xcoff_get_n_import_files (abfd) != 0)
395	return GDB_OSABI_UNKNOWN;
396
397	return GDB_OSABI_LYNXOS178;
398	}
399
400	/* Callback for powerpc-lynx178 initialization. */
401
402	static void
403	rs6000_lynx178_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
404	{
405	set_gdbarch_push_dummy_call (gdbarch, rs6000_lynx178_push_dummy_call);
406	set_gdbarch_return_value (gdbarch, rs6000_lynx178_return_value);
407	set_gdbarch_long_double_bit (gdbarch, 8 * TARGET_CHAR_BIT);
408	}
409
410	/* -Wmissing-prototypes. */
411	extern initialize_file_ftype _initialize_rs6000_lynx178_tdep;
412
413	void
414	_initialize_rs6000_lynx178_tdep (void)
415	{
416	gdbarch_register_osabi_sniffer (bfd_arch_rs6000,
417	bfd_target_xcoff_flavour,
418	rs6000_lynx178_osabi_sniffer);
419	gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_LYNXOS178,
420	rs6000_lynx178_init_osabi);
421	}
422