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7b112f9c JT |
1 | /* Target-dependent code for PowerPC systems using the SVR4 ABI |
2 | for GDB, the GNU debugger. | |
3 | ||
4 | Copyright 2000, 2001, 2002 Free Software Foundation, Inc. | |
5 | ||
6 | This file is part of GDB. | |
7 | ||
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. | |
12 | ||
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. | |
17 | ||
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. */ | |
22 | ||
23 | #include "defs.h" | |
24 | #include "gdbcore.h" | |
25 | #include "inferior.h" | |
26 | #include "regcache.h" | |
27 | #include "value.h" | |
bdf64bac | 28 | #include "gdb_string.h" |
7b112f9c JT |
29 | |
30 | #include "ppc-tdep.h" | |
31 | ||
7b112f9c JT |
32 | /* Pass the arguments in either registers, or in the stack. Using the |
33 | ppc sysv ABI, the first eight words of the argument list (that might | |
34 | be less than eight parameters if some parameters occupy more than one | |
35 | word) are passed in r3..r10 registers. float and double parameters are | |
36 | passed in fpr's, in addition to that. Rest of the parameters if any | |
37 | are passed in user stack. | |
38 | ||
39 | If the function is returning a structure, then the return address is passed | |
40 | in r3, then the first 7 words of the parametes can be passed in registers, | |
41 | starting from r4. */ | |
42 | ||
43 | CORE_ADDR | |
77b2b6d4 AC |
44 | ppc_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, CORE_ADDR func_addr, |
45 | struct regcache *regcache, CORE_ADDR bp_addr, | |
46 | int nargs, struct value **args, CORE_ADDR sp, | |
47 | int struct_return, CORE_ADDR struct_addr) | |
7b112f9c | 48 | { |
0a613259 | 49 | struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); |
68856ea3 AC |
50 | const CORE_ADDR saved_sp = read_sp (); |
51 | int argspace = 0; /* 0 is an initial wrong guess. */ | |
52 | int write_pass; | |
7b112f9c | 53 | |
68856ea3 | 54 | /* Go through the argument list twice. |
7b112f9c | 55 | |
68856ea3 AC |
56 | Pass 1: Figure out how much new stack space is required for |
57 | arguments and pushed values. Unlike the PowerOpen ABI, the SysV | |
58 | ABI doesn't reserve any extra space for parameters which are put | |
59 | in registers, but does always push structures and then pass their | |
60 | address. | |
7a41266b | 61 | |
68856ea3 AC |
62 | Pass 2: Replay the same computation but this time also write the |
63 | values out to the target. */ | |
7b112f9c | 64 | |
68856ea3 AC |
65 | for (write_pass = 0; write_pass < 2; write_pass++) |
66 | { | |
67 | int argno; | |
68 | /* Next available floating point register for float and double | |
69 | arguments. */ | |
70 | int freg = 1; | |
71 | /* Next available general register for non-float, non-vector | |
72 | arguments. */ | |
73 | int greg = 3; | |
74 | /* Next available vector register for vector arguments. */ | |
75 | int vreg = 2; | |
76 | /* Arguments start above the "LR save word" and "Back chain". */ | |
77 | int argoffset = 2 * tdep->wordsize; | |
78 | /* Structures start after the arguments. */ | |
79 | int structoffset = argoffset + argspace; | |
80 | ||
81 | /* If the function is returning a `struct', then the first word | |
82 | (which will be passed in r3) is used for struct return | |
83 | address. In that case we should advance one word and start | |
84 | from r4 register to copy parameters. */ | |
85 | if (struct_return) | |
7b112f9c | 86 | { |
68856ea3 AC |
87 | if (write_pass) |
88 | regcache_cooked_write_signed (regcache, | |
89 | tdep->ppc_gp0_regnum + greg, | |
90 | struct_addr); | |
91 | greg++; | |
7b112f9c | 92 | } |
68856ea3 AC |
93 | |
94 | for (argno = 0; argno < nargs; argno++) | |
7b112f9c | 95 | { |
68856ea3 AC |
96 | struct value *arg = args[argno]; |
97 | struct type *type = check_typedef (VALUE_TYPE (arg)); | |
98 | int len = TYPE_LENGTH (type); | |
99 | char *val = VALUE_CONTENTS (arg); | |
100 | ||
101 | if (TYPE_CODE (type) == TYPE_CODE_FLT | |
102 | && ppc_floating_point_unit_p (current_gdbarch) | |
103 | && len <= 8) | |
7b112f9c | 104 | { |
68856ea3 AC |
105 | /* Floating point value converted to "double" then |
106 | passed in an FP register, when the registers run out, | |
107 | 8 byte aligned stack is used. */ | |
108 | if (freg <= 8) | |
109 | { | |
110 | if (write_pass) | |
111 | { | |
112 | /* Always store the floating point value using | |
113 | the register's floating-point format. */ | |
114 | char regval[MAX_REGISTER_SIZE]; | |
115 | struct type *regtype | |
116 | = register_type (gdbarch, FP0_REGNUM + freg); | |
117 | convert_typed_floating (val, type, regval, regtype); | |
118 | regcache_cooked_write (regcache, FP0_REGNUM + freg, | |
119 | regval); | |
120 | } | |
121 | freg++; | |
122 | } | |
7b112f9c JT |
123 | else |
124 | { | |
68856ea3 AC |
125 | /* SysV ABI converts floats to doubles before |
126 | writing them to an 8 byte aligned stack location. */ | |
127 | argoffset = align_up (argoffset, 8); | |
128 | if (write_pass) | |
129 | { | |
130 | char memval[8]; | |
131 | struct type *memtype; | |
132 | switch (TARGET_BYTE_ORDER) | |
133 | { | |
134 | case BFD_ENDIAN_BIG: | |
135 | memtype = builtin_type_ieee_double_big; | |
136 | break; | |
137 | case BFD_ENDIAN_LITTLE: | |
138 | memtype = builtin_type_ieee_double_little; | |
139 | break; | |
140 | default: | |
141 | internal_error (__FILE__, __LINE__, "bad switch"); | |
142 | } | |
143 | convert_typed_floating (val, type, memval, memtype); | |
144 | write_memory (sp + argoffset, val, len); | |
145 | } | |
146 | argoffset += 8; | |
7b112f9c JT |
147 | } |
148 | } | |
68856ea3 AC |
149 | else if (len == 8 |
150 | && (TYPE_CODE (type) == TYPE_CODE_INT /* long long */ | |
151 | || (!ppc_floating_point_unit_p (current_gdbarch) | |
152 | && TYPE_CODE (type) == TYPE_CODE_FLT))) /* double */ | |
7b112f9c | 153 | { |
68856ea3 AC |
154 | /* "long long" or "double" passed in an odd/even |
155 | register pair with the low addressed word in the odd | |
156 | register and the high addressed word in the even | |
157 | register, or when the registers run out an 8 byte | |
158 | aligned stack location. */ | |
159 | if (greg > 9) | |
160 | { | |
161 | /* Just in case GREG was 10. */ | |
162 | greg = 11; | |
163 | argoffset = align_up (argoffset, 8); | |
164 | if (write_pass) | |
165 | write_memory (sp + argoffset, val, len); | |
166 | argoffset += 8; | |
167 | } | |
168 | else if (tdep->wordsize == 8) | |
169 | { | |
170 | if (write_pass) | |
171 | regcache_cooked_write (regcache, | |
172 | tdep->ppc_gp0_regnum + greg, | |
173 | val); | |
174 | greg += 1; | |
175 | } | |
176 | else | |
177 | { | |
178 | /* Must start on an odd register - r3/r4 etc. */ | |
179 | if ((greg & 1) == 0) | |
180 | greg++; | |
181 | if (write_pass) | |
182 | { | |
183 | regcache_cooked_write (regcache, | |
184 | tdep->ppc_gp0_regnum + greg + 0, | |
185 | val + 0); | |
186 | regcache_cooked_write (regcache, | |
187 | tdep->ppc_gp0_regnum + greg + 1, | |
188 | val + 4); | |
189 | } | |
190 | greg += 2; | |
191 | } | |
7b112f9c | 192 | } |
68856ea3 AC |
193 | else if (len == 16 |
194 | && TYPE_CODE (type) == TYPE_CODE_ARRAY | |
195 | && TYPE_VECTOR (type) | |
196 | && tdep->ppc_vr0_regnum >= 0) | |
7b112f9c | 197 | { |
68856ea3 AC |
198 | /* Vector parameter passed in an Altivec register, or |
199 | when that runs out, 16 byte aligned stack location. */ | |
7b112f9c JT |
200 | if (vreg <= 13) |
201 | { | |
68856ea3 AC |
202 | if (write_pass) |
203 | regcache_cooked_write (current_regcache, | |
204 | tdep->ppc_vr0_regnum + vreg, | |
205 | val); | |
7b112f9c JT |
206 | vreg++; |
207 | } | |
208 | else | |
209 | { | |
68856ea3 AC |
210 | argoffset = align_up (argoffset, 16); |
211 | if (write_pass) | |
212 | write_memory (sp + argoffset, val, 16); | |
7b112f9c JT |
213 | argoffset += 16; |
214 | } | |
215 | } | |
0a613259 AC |
216 | else if (len == 8 |
217 | && TYPE_CODE (type) == TYPE_CODE_ARRAY | |
68856ea3 AC |
218 | && TYPE_VECTOR (type) |
219 | && tdep->ppc_ev0_regnum >= 0) | |
0a613259 | 220 | { |
68856ea3 AC |
221 | /* Vector parameter passed in an e500 register, or when |
222 | that runs out, 8 byte aligned stack location. Note | |
223 | that since e500 vector and general purpose registers | |
224 | both map onto the same underlying register set, a | |
225 | "greg" and not a "vreg" is consumed here. A cooked | |
226 | write stores the value in the correct locations | |
227 | within the raw register cache. */ | |
0a613259 AC |
228 | if (greg <= 10) |
229 | { | |
68856ea3 AC |
230 | if (write_pass) |
231 | regcache_cooked_write (current_regcache, | |
232 | tdep->ppc_ev0_regnum + greg, | |
233 | val); | |
0a613259 AC |
234 | greg++; |
235 | } | |
236 | else | |
237 | { | |
68856ea3 AC |
238 | argoffset = align_up (argoffset, 8); |
239 | if (write_pass) | |
240 | write_memory (sp + argoffset, val, 8); | |
0a613259 AC |
241 | argoffset += 8; |
242 | } | |
243 | } | |
68856ea3 AC |
244 | else |
245 | { | |
246 | /* Reduce the parameter down to something that fits in a | |
247 | "word". */ | |
248 | char word[MAX_REGISTER_SIZE]; | |
249 | memset (word, 0, MAX_REGISTER_SIZE); | |
250 | if (len > tdep->wordsize | |
251 | || TYPE_CODE (type) == TYPE_CODE_STRUCT | |
252 | || TYPE_CODE (type) == TYPE_CODE_UNION) | |
253 | { | |
254 | /* Structs and large values are put on an 8 byte | |
255 | aligned stack ... */ | |
256 | structoffset = align_up (structoffset, 8); | |
257 | if (write_pass) | |
258 | write_memory (sp + structoffset, val, len); | |
259 | /* ... and then a "word" pointing to that address is | |
260 | passed as the parameter. */ | |
261 | store_unsigned_integer (word, tdep->wordsize, | |
262 | sp + structoffset); | |
263 | structoffset += len; | |
264 | } | |
265 | else if (TYPE_CODE (type) == TYPE_CODE_INT) | |
266 | /* Sign or zero extend the "int" into a "word". */ | |
267 | store_unsigned_integer (word, tdep->wordsize, | |
268 | unpack_long (type, val)); | |
269 | else | |
270 | /* Always goes in the low address. */ | |
271 | memcpy (word, val, len); | |
272 | /* Store that "word" in a register, or on the stack. | |
273 | The words have "4" byte alignment. */ | |
274 | if (greg <= 10) | |
275 | { | |
276 | if (write_pass) | |
277 | regcache_cooked_write (regcache, | |
278 | tdep->ppc_gp0_regnum + greg, | |
279 | word); | |
280 | greg++; | |
281 | } | |
282 | else | |
283 | { | |
284 | argoffset = align_up (argoffset, tdep->wordsize); | |
285 | if (write_pass) | |
286 | write_memory (sp + argoffset, word, tdep->wordsize); | |
287 | argoffset += tdep->wordsize; | |
288 | } | |
289 | } | |
290 | } | |
291 | ||
292 | /* Compute the actual stack space requirements. */ | |
293 | if (!write_pass) | |
294 | { | |
295 | /* Remember the amount of space needed by the arguments. */ | |
296 | argspace = argoffset; | |
297 | /* Allocate space for both the arguments and the structures. */ | |
298 | sp -= (argoffset + structoffset); | |
299 | /* Ensure that the stack is still 16 byte aligned. */ | |
300 | sp = align_down (sp, 16); | |
301 | } | |
7b112f9c JT |
302 | } |
303 | ||
68856ea3 AC |
304 | /* Update %sp. */ |
305 | regcache_cooked_write_signed (regcache, SP_REGNUM, sp); | |
306 | ||
307 | /* Write the backchain (it occupies WORDSIZED bytes). */ | |
308 | write_memory_signed_integer (sp, tdep->wordsize, saved_sp); | |
309 | ||
e56a0ecc AC |
310 | /* Point the inferior function call's return address at the dummy's |
311 | breakpoint. */ | |
68856ea3 | 312 | regcache_cooked_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr); |
e56a0ecc | 313 | |
7b112f9c JT |
314 | return sp; |
315 | } | |
316 | ||
7b112f9c JT |
317 | /* Structures 8 bytes or less long are returned in the r3 & r4 |
318 | registers, according to the SYSV ABI. */ | |
319 | int | |
320 | ppc_sysv_abi_use_struct_convention (int gcc_p, struct type *value_type) | |
321 | { | |
0a613259 | 322 | if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8) |
7b112f9c JT |
323 | && TYPE_VECTOR (value_type)) |
324 | return 0; | |
325 | ||
326 | return (TYPE_LENGTH (value_type) > 8); | |
327 | } |