1 /* Target-dependent code for PowerPC systems using the SVR4 ABI
2 for GDB, the GNU debugger.
4 Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
28 #include "gdb_string.h"
32 /* round2 rounds x up to the nearest multiple of s assuming that s is a
36 #define round2(x,s) ((((long) (x) - 1) & ~(long)((s)-1)) + (s))
38 /* Pass the arguments in either registers, or in the stack. Using the
39 ppc sysv ABI, the first eight words of the argument list (that might
40 be less than eight parameters if some parameters occupy more than one
41 word) are passed in r3..r10 registers. float and double parameters are
42 passed in fpr's, in addition to that. Rest of the parameters if any
43 are passed in user stack.
45 If the function is returning a structure, then the return address is passed
46 in r3, then the first 7 words of the parametes can be passed in registers,
50 ppc_sysv_abi_push_arguments (int nargs, struct value **args, CORE_ADDR sp,
51 int struct_return, CORE_ADDR struct_addr)
54 /* Next available general register for non-float, non-vector arguments. */
56 /* Next available floating point register for float arguments. */
58 /* Next available vector register for vector arguments. */
68 struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
70 greg = struct_return ? 4 : 3;
76 /* Figure out how much new stack space is required for arguments
77 which don't fit in registers. Unlike the PowerOpen ABI, the
78 SysV ABI doesn't reserve any extra space for parameters which
79 are put in registers. */
80 for (argno = 0; argno < nargs; argno++)
82 struct value *arg = args[argno];
83 type = check_typedef (VALUE_TYPE (arg));
84 len = TYPE_LENGTH (type);
86 if (TYPE_CODE (type) == TYPE_CODE_FLT
87 && ppc_floating_point_unit_p (current_gdbarch))
93 /* SysV ABI converts floats to doubles when placed in
94 memory and requires 8 byte alignment */
95 if (argstkspace & 0x4)
101 && (TYPE_CODE (type) == TYPE_CODE_INT /* long long */
102 || (!ppc_floating_point_unit_p (current_gdbarch)
103 && TYPE_CODE (type) == TYPE_CODE_FLT))) /* double */
108 if (argstkspace & 0x4)
119 else if (!TYPE_VECTOR (type))
122 || TYPE_CODE (type) == TYPE_CODE_STRUCT
123 || TYPE_CODE (type) == TYPE_CODE_UNION)
125 /* Rounding to the nearest multiple of 8 may not be necessary,
126 but it is safe. Particularly since we don't know the
127 field types of the structure */
128 structstkspace += round2 (len, 8);
138 && TYPE_CODE (type) == TYPE_CODE_ARRAY
139 && TYPE_VECTOR (type))
145 /* Vector arguments must be aligned to 16 bytes on
147 argstkspace += round2 (argstkspace, 16);
152 && TYPE_CODE (type) == TYPE_CODE_ARRAY
153 && TYPE_VECTOR (type))
159 /* Vector arguments must be aligned to 8 bytes on
161 argstkspace += round2 (argstkspace, 8);
168 /* Get current SP location */
169 saved_sp = read_sp ();
171 sp -= argstkspace + structstkspace;
173 /* Allocate space for backchain and callee's saved lr */
176 /* Make sure that we maintain 16 byte alignment */
179 /* Update %sp before proceeding any further */
180 write_register (SP_REGNUM, sp);
182 /* write the backchain */
183 store_address (old_sp_buf, 4, saved_sp);
184 write_memory (sp, old_sp_buf, 4);
187 structoffset = argoffset + argstkspace;
192 /* Fill in r3 with the return structure, if any */
195 write_register (tdep->ppc_gp0_regnum + greg, struct_addr);
199 /* Now fill in the registers and stack... */
200 for (argno = 0; argno < nargs; argno++)
202 struct value *arg = args[argno];
203 char *val = VALUE_CONTENTS (arg);
204 type = check_typedef (VALUE_TYPE (arg));
205 len = TYPE_LENGTH (type);
207 if (TYPE_CODE (type) == TYPE_CODE_FLT
208 && ppc_floating_point_unit_p (current_gdbarch))
215 "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno);
216 regval = extract_unsigned_integer (val, len);
217 write_register (FP0_REGNUM + freg, regval);
222 /* SysV ABI converts floats to doubles when placed in
223 memory and requires 8 byte alignment */
224 /* FIXME: Convert floats to doubles */
227 write_memory (sp + argoffset, val, len);
232 && (TYPE_CODE (type) == TYPE_CODE_INT /* long long */
233 || (!ppc_floating_point_unit_p (current_gdbarch)
234 && TYPE_CODE (type) == TYPE_CODE_FLT))) /* double */
241 write_memory (sp + argoffset, val, len);
249 regval = extract_unsigned_integer (val, 4);
250 write_register (tdep->ppc_gp0_regnum + greg, regval);
251 regval = extract_unsigned_integer (val + 4, 4);
252 write_register (tdep->ppc_gp0_regnum + greg + 1, regval);
256 else if (!TYPE_VECTOR (type))
260 || TYPE_CODE (type) == TYPE_CODE_STRUCT
261 || TYPE_CODE (type) == TYPE_CODE_UNION)
263 write_memory (sp + structoffset, val, len);
264 store_address (val_buf, 4, sp + structoffset);
265 structoffset += round2 (len, 8);
269 memset (val_buf, 0, 4);
270 memcpy (val_buf, val, len);
274 ULONGEST regval = extract_unsigned_integer (val_buf, 4);
275 write_register (tdep->ppc_gp0_regnum + greg, regval);
280 write_memory (sp + argoffset, val_buf, 4);
287 && TYPE_CODE (type) == TYPE_CODE_ARRAY
288 && TYPE_VECTOR (type))
290 char *v_val_buf = alloca (16);
291 memset (v_val_buf, 0, 16);
292 memcpy (v_val_buf, val, len);
295 regcache_cooked_write (current_regcache,
296 tdep->ppc_vr0_regnum + vreg,
302 write_memory (sp + argoffset, v_val_buf, 16);
307 && TYPE_CODE (type) == TYPE_CODE_ARRAY
308 && TYPE_VECTOR (type))
310 char *v_val_buf = alloca (8);
311 memset (v_val_buf, 0, 8);
312 memcpy (v_val_buf, val, len);
315 regcache_cooked_write (current_regcache,
316 tdep->ppc_ev0_regnum + greg,
322 write_memory (sp + argoffset, v_val_buf, 8);
329 target_store_registers (-1);
333 /* Until November 2001, gcc was not complying to the SYSV ABI for
334 returning structures less than or equal to 8 bytes in size. It was
335 returning everything in memory. When this was corrected, it wasn't
336 fixed for native platforms. */
338 ppc_sysv_abi_broken_use_struct_convention (int gcc_p, struct type *value_type)
340 if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8)
341 && TYPE_VECTOR (value_type))
344 return generic_use_struct_convention (gcc_p, value_type);
347 /* Structures 8 bytes or less long are returned in the r3 & r4
348 registers, according to the SYSV ABI. */
350 ppc_sysv_abi_use_struct_convention (int gcc_p, struct type *value_type)
352 if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8)
353 && TYPE_VECTOR (value_type))
356 return (TYPE_LENGTH (value_type) > 8);