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

/* Copyright (C) 2012-2016 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.

	     Always store the floating point value using the register's
	     floating-point format.  */
	  const int fp_regnum = tdep->ppc_fp0_regnum + 1 + f_argno;
	  gdb_byte reg_val[MAX_REGISTER_SIZE];
	  struct type *reg_type = register_type (gdbarch, fp_regnum);

	  gdb_assert (len <= 8);

	  convert_typed_floating (value_contents (arg), type,
				  reg_val, reg_type);
	  regcache_cooked_write (regcache, fp_regnum, reg_val);
	  ++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.  */
	  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
618f726f	1	/* Copyright (C) 2012-2016 Free Software Foundation, Inc.
d5367fe1 JB	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
36d1c68c JB	103	there is no way we would run out of them.
	104
	105	Always store the floating point value using the register's
	106	floating-point format. */
	107	const int fp_regnum = tdep->ppc_fp0_regnum + 1 + f_argno;
	108	gdb_byte reg_val[MAX_REGISTER_SIZE];
	109	struct type *reg_type = register_type (gdbarch, fp_regnum);
d5367fe1 JB	110
	111	gdb_assert (len <= 8);
	112
36d1c68c JB	113	convert_typed_floating (value_contents (arg), type,
	114	reg_val, reg_type);
	115	regcache_cooked_write (regcache, fp_regnum, reg_val);
d5367fe1 JB	116	++f_argno;
	117	}
	118
	119	if (len > reg_size)
	120	{
	121
	122	/* Argument takes more than one register. */
	123	while (argbytes < len)
	124	{
	125	gdb_byte word[MAX_REGISTER_SIZE];
	126	memset (word, 0, reg_size);
	127	memcpy (word,
	128	((char *) value_contents (arg)) + argbytes,
	129	(len - argbytes) > reg_size
	130	? reg_size : len - argbytes);
	131	regcache_cooked_write (regcache,
	132	tdep->ppc_gp0_regnum + 3 + ii,
	133	word);
	134	++ii, argbytes += reg_size;
	135
	136	if (ii >= 8)
	137	goto ran_out_of_registers_for_arguments;
	138	}
	139	argbytes = 0;
	140	--ii;
	141	}
	142	else
	143	{
	144	/* Argument can fit in one register. No problem. */
d5367fe1 JB	145	gdb_byte word[MAX_REGISTER_SIZE];
	146
	147	memset (word, 0, reg_size);
	148	memcpy (word, value_contents (arg), len);
	149	regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3 +ii, word);
	150	}
	151	++argno;
	152	}
	153
	154	ran_out_of_registers_for_arguments:
	155
	156	regcache_cooked_read_unsigned (regcache,
	157	gdbarch_sp_regnum (gdbarch),
	158	&saved_sp);
	159
	160	/* Location for 8 parameters are always reserved. */
	161	sp -= wordsize * 8;
	162
	163	/* Another six words for back chain, TOC register, link register, etc. */
	164	sp -= wordsize * 6;
	165
	166	/* Stack pointer must be quadword aligned. */
	167	sp = align_down (sp, 16);
	168
	169	/* If there are more arguments, allocate space for them in
	170	the stack, then push them starting from the ninth one. */
	171
	172	if ((argno < nargs) \|\| argbytes)
	173	{
	174	int space = 0, jj;
	175
	176	if (argbytes)
	177	{
	178	space += align_up (len - argbytes, 4);
	179	jj = argno + 1;
	180	}
	181	else
	182	jj = argno;
	183
	184	for (; jj < nargs; ++jj)
	185	{
	186	struct value *val = args[jj];
	187
	188	space += align_up (TYPE_LENGTH (value_type (val)), 4);
	189	}
	190
	191	/* Add location required for the rest of the parameters. */
	192	space = align_up (space, 16);
	193	sp -= space;
	194
	195	/* This is another instance we need to be concerned about
	196	securing our stack space. If we write anything underneath %sp
	197	(r1), we might conflict with the kernel who thinks he is free
	198	to use this area. So, update %sp first before doing anything
	199	else. */
	200
	201	regcache_raw_write_signed (regcache,
	202	gdbarch_sp_regnum (gdbarch), sp);
	203
	204	/* If the last argument copied into the registers didn't fit there
	205	completely, push the rest of it into stack. */
	206
	207	if (argbytes)
	208	{
209	write_memory (sp + 24 + (ii * 4),
210	value_contents (arg) + argbytes,
211	len - argbytes);
212	++argno;
213	ii += align_up (len - argbytes, 4) / 4;
214	}
215
216	/* Push the rest of the arguments into stack. */
217	for (; argno < nargs; ++argno)
218	{
219
220	arg = args[argno];
221	type = check_typedef (value_type (arg));
222	len = TYPE_LENGTH (type);
223
224
225	/* Float types should be passed in fpr's, as well as in the
226	stack. */
227	if (TYPE_CODE (type) == TYPE_CODE_FLT && f_argno < 13)
228	{
229
230	gdb_assert (len <= 8);
231
232	regcache_cooked_write (regcache,
233	tdep->ppc_fp0_regnum + 1 + f_argno,
234	value_contents (arg));
235	++f_argno;
236	}
237
238	write_memory (sp + 24 + (ii * 4), value_contents (arg), len);
239	ii += align_up (len, 4) / 4;
240	}
241	}
242
243	/* Set the stack pointer. According to the ABI, the SP is meant to
244	be set _before_ the corresponding stack space is used. On AIX,
245	this even applies when the target has been completely stopped!
246	Not doing this can lead to conflicts with the kernel which thinks
247	that it still has control over this not-yet-allocated stack
248	region. */
249	regcache_raw_write_signed (regcache, gdbarch_sp_regnum (gdbarch), sp);
250
251	/* Set back chain properly. */
252	store_unsigned_integer (tmp_buffer, wordsize, byte_order, saved_sp);
253	write_memory (sp, tmp_buffer, wordsize);
254
255	/* Point the inferior function call's return address at the dummy's
256	breakpoint. */
257	regcache_raw_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr);
258
259	target_store_registers (regcache, -1);
260	return sp;
261	}
262
263	/* Implement the "return_value" gdbarch method. */
264
265	static enum return_value_convention
266	rs6000_lynx178_return_value (struct gdbarch gdbarch, struct value function,
267	struct type valtype, struct regcache regcache,
268	gdb_byte readbuf, const gdb_byte writebuf)
269	{
270	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
271	enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
272
273	/* The calling convention this function implements assumes the
274	processor has floating-point registers. We shouldn't be using it
275	on PowerPC variants that lack them. */
276	gdb_assert (ppc_floating_point_unit_p (gdbarch));
277
278	/* AltiVec extension: Functions that declare a vector data type as a
279	return value place that return value in VR2. */
280	if (TYPE_CODE (valtype) == TYPE_CODE_ARRAY && TYPE_VECTOR (valtype)
281	&& TYPE_LENGTH (valtype) == 16)
282	{
283	if (readbuf)
284	regcache_cooked_read (regcache, tdep->ppc_vr0_regnum + 2, readbuf);
285	if (writebuf)
286	regcache_cooked_write (regcache, tdep->ppc_vr0_regnum + 2, writebuf);
287
288	return RETURN_VALUE_REGISTER_CONVENTION;
289	}
290
291	/* If the called subprogram returns an aggregate, there exists an
292	implicit first argument, whose value is the address of a caller-
293	allocated buffer into which the callee is assumed to store its
294	return value. All explicit parameters are appropriately
295	relabeled. */
296	if (TYPE_CODE (valtype) == TYPE_CODE_STRUCT
297	\|\| TYPE_CODE (valtype) == TYPE_CODE_UNION
298	\|\| TYPE_CODE (valtype) == TYPE_CODE_ARRAY)
299	return RETURN_VALUE_STRUCT_CONVENTION;
300
301	/* Scalar floating-point values are returned in FPR1 for float or
302	double, and in FPR1:FPR2 for quadword precision. Fortran
303	complex8 and complex16 are returned in FPR1:FPR2, and
304	complex32 is returned in FPR1:FPR4. /
305	if (TYPE_CODE (valtype) == TYPE_CODE_FLT
306	&& (TYPE_LENGTH (valtype) == 4 \|\| TYPE_LENGTH (valtype) == 8))
307	{
308	struct type *regtype = register_type (gdbarch, tdep->ppc_fp0_regnum);
309	gdb_byte regval[8];
310
311	/* FIXME: kettenis/2007-01-01: Add support for quadword
312	precision and complex. */
313
314	if (readbuf)
315	{
316	regcache_cooked_read (regcache, tdep->ppc_fp0_regnum + 1, regval);
317	convert_typed_floating (regval, regtype, readbuf, valtype);
318	}
319	if (writebuf)
320	{
321	convert_typed_floating (writebuf, valtype, regval, regtype);
322	regcache_cooked_write (regcache, tdep->ppc_fp0_regnum + 1, regval);
323	}
324
325	return RETURN_VALUE_REGISTER_CONVENTION;
326	}
327
328	/* Values of the types int, long, short, pointer, and char (length
329	is less than or equal to four bytes), as well as bit values of
330	lengths less than or equal to 32 bits, must be returned right
331	justified in GPR3 with signed values sign extended and unsigned
332	values zero extended, as necessary. */
333	if (TYPE_LENGTH (valtype) <= tdep->wordsize)
334	{
335	if (readbuf)
336	{
337	ULONGEST regval;
338
339	/* For reading we don't have to worry about sign extension. */
340	regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
341	&regval);
342	store_unsigned_integer (readbuf, TYPE_LENGTH (valtype), byte_order,
343	regval);
344	}
345	if (writebuf)
346	{
347	/* For writing, use unpack_long since that should handle any
348	required sign extension. */
349	regcache_cooked_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
350	unpack_long (valtype, writebuf));
351	}
352
353	return RETURN_VALUE_REGISTER_CONVENTION;
354	}
355
356	/* Eight-byte non-floating-point scalar values must be returned in
357	GPR3:GPR4. */
358
359	if (TYPE_LENGTH (valtype) == 8)
360	{
361	gdb_assert (TYPE_CODE (valtype) != TYPE_CODE_FLT);
362	gdb_assert (tdep->wordsize == 4);
363
364	if (readbuf)
365	{
366	gdb_byte regval[8];
367
368	regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 3, regval);
369	regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 4,
370	regval + 4);
371	memcpy (readbuf, regval, 8);
372	}
373	if (writebuf)
374	{
375	regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3, writebuf);
376	regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 4,
377	writebuf + 4);
378	}
379
380	return RETURN_VALUE_REGISTER_CONVENTION;
381	}
382
383	return RETURN_VALUE_STRUCT_CONVENTION;
384	}
385
386	/* PowerPC Lynx178 OSABI sniffer. */
387
388	static enum gdb_osabi
389	rs6000_lynx178_osabi_sniffer (bfd *abfd)
390	{
391	if (bfd_get_flavour (abfd) != bfd_target_xcoff_flavour)
392	return GDB_OSABI_UNKNOWN;
393
394	/* The only noticeable difference between Lynx178 XCOFF files and
395	AIX XCOFF files comes from the fact that there are no shared
396	libraries on Lynx178. So if the number of import files is
397	different from zero, it cannot be a Lynx178 binary. */
398	if (xcoff_get_n_import_files (abfd) != 0)
399	return GDB_OSABI_UNKNOWN;
400
401	return GDB_OSABI_LYNXOS178;
402	}
403
404	/* Callback for powerpc-lynx178 initialization. */
405
406	static void
407	rs6000_lynx178_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
408	{
409	set_gdbarch_push_dummy_call (gdbarch, rs6000_lynx178_push_dummy_call);
410	set_gdbarch_return_value (gdbarch, rs6000_lynx178_return_value);
411	set_gdbarch_long_double_bit (gdbarch, 8 * TARGET_CHAR_BIT);
412	}
413
414	/* -Wmissing-prototypes. */
415	extern initialize_file_ftype _initialize_rs6000_lynx178_tdep;
416
417	void
418	_initialize_rs6000_lynx178_tdep (void)
419	{
420	gdbarch_register_osabi_sniffer (bfd_arch_rs6000,
421	bfd_target_xcoff_flavour,
422	rs6000_lynx178_osabi_sniffer);
423	gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_LYNXOS178,
424	rs6000_lynx178_init_osabi);
425	}
426