1 /* Target-dependent code for Atmel AVR, for GDB.
3 Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
4 2006, 2007 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 3 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, see <http://www.gnu.org/licenses/>. */
21 /* Contributed by Theodore A. Roth, troth@openavr.org */
23 /* Portions of this file were taken from the original gdb-4.18 patch developed
24 by Denis Chertykov, denisc@overta.ru */
28 #include "frame-unwind.h"
29 #include "frame-base.h"
30 #include "trad-frame.h"
36 #include "arch-utils.h"
38 #include "gdb_string.h"
43 (AVR micros are pure Harvard Architecture processors.)
45 The AVR family of microcontrollers have three distinctly different memory
46 spaces: flash, sram and eeprom. The flash is 16 bits wide and is used for
47 the most part to store program instructions. The sram is 8 bits wide and is
48 used for the stack and the heap. Some devices lack sram and some can have
49 an additional external sram added on as a peripheral.
51 The eeprom is 8 bits wide and is used to store data when the device is
52 powered down. Eeprom is not directly accessible, it can only be accessed
53 via io-registers using a special algorithm. Accessing eeprom via gdb's
54 remote serial protocol ('m' or 'M' packets) looks difficult to do and is
55 not included at this time.
57 [The eeprom could be read manually via ``x/b <eaddr + AVR_EMEM_START>'' or
58 written using ``set {unsigned char}<eaddr + AVR_EMEM_START>''. For this to
59 work, the remote target must be able to handle eeprom accesses and perform
60 the address translation.]
62 All three memory spaces have physical addresses beginning at 0x0. In
63 addition, the flash is addressed by gcc/binutils/gdb with respect to 8 bit
64 bytes instead of the 16 bit wide words used by the real device for the
67 In order for remote targets to work correctly, extra bits must be added to
68 addresses before they are send to the target or received from the target
69 via the remote serial protocol. The extra bits are the MSBs and are used to
70 decode which memory space the address is referring to. */
73 #define XMALLOC(TYPE) ((TYPE*) xmalloc (sizeof (TYPE)))
76 #define EXTRACT_INSN(addr) extract_unsigned_integer(addr,2)
78 /* Constants: prefixed with AVR_ to avoid name space clashes */
92 AVR_NUM_REGS
= 32 + 1 /*SREG*/ + 1 /*SP*/ + 1 /*PC*/,
93 AVR_NUM_REG_BYTES
= 32 + 1 /*SREG*/ + 2 /*SP*/ + 4 /*PC*/,
95 AVR_PC_REG_INDEX
= 35, /* index into array of registers */
97 AVR_MAX_PROLOGUE_SIZE
= 64, /* bytes */
99 /* Count of pushed registers. From r2 to r17 (inclusively), r28, r29 */
102 /* Number of the last pushed register. r17 for current avr-gcc */
103 AVR_LAST_PUSHED_REGNUM
= 17,
105 AVR_ARG1_REGNUM
= 24, /* Single byte argument */
106 AVR_ARGN_REGNUM
= 25, /* Multi byte argments */
108 AVR_RET1_REGNUM
= 24, /* Single byte return value */
109 AVR_RETN_REGNUM
= 25, /* Multi byte return value */
111 /* FIXME: TRoth/2002-01-??: Can we shift all these memory masks left 8
112 bits? Do these have to match the bfd vma values?. It sure would make
113 things easier in the future if they didn't need to match.
115 Note: I chose these values so as to be consistent with bfd vma
118 TRoth/2002-04-08: There is already a conflict with very large programs
119 in the mega128. The mega128 has 128K instruction bytes (64K words),
120 thus the Most Significant Bit is 0x10000 which gets masked off my
123 The problem manifests itself when trying to set a breakpoint in a
124 function which resides in the upper half of the instruction space and
125 thus requires a 17-bit address.
127 For now, I've just removed the EEPROM mask and changed AVR_MEM_MASK
128 from 0x00ff0000 to 0x00f00000. Eeprom is not accessible from gdb yet,
129 but could be for some remote targets by just adding the correct offset
130 to the address and letting the remote target handle the low-level
131 details of actually accessing the eeprom. */
133 AVR_IMEM_START
= 0x00000000, /* INSN memory */
134 AVR_SMEM_START
= 0x00800000, /* SRAM memory */
136 /* No eeprom mask defined */
137 AVR_MEM_MASK
= 0x00f00000, /* mask to determine memory space */
139 AVR_EMEM_START
= 0x00810000, /* EEPROM memory */
140 AVR_MEM_MASK
= 0x00ff0000, /* mask to determine memory space */
146 NORMAL and CALL are the typical types (the -mcall-prologues gcc option
147 causes the generation of the CALL type prologues). */
150 AVR_PROLOGUE_NONE
, /* No prologue */
152 AVR_PROLOGUE_CALL
, /* -mcall-prologues */
154 AVR_PROLOGUE_INTR
, /* interrupt handler */
155 AVR_PROLOGUE_SIG
, /* signal handler */
158 /* Any function with a frame looks like this
159 ....... <-SP POINTS HERE
160 LOCALS1 <-FP POINTS HERE
169 struct avr_unwind_cache
171 /* The previous frame's inner most stack address. Used as this
172 frame ID's stack_addr. */
174 /* The frame's base, optionally used by the high-level debug info. */
178 /* Table indicating the location of each and every register. */
179 struct trad_frame_saved_reg
*saved_regs
;
184 /* FIXME: TRoth: is there anything to put here? */
188 /* Lookup the name of a register given it's number. */
191 avr_register_name (int regnum
)
193 static char *register_names
[] = {
194 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
195 "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
196 "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
197 "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
202 if (regnum
>= (sizeof (register_names
) / sizeof (*register_names
)))
204 return register_names
[regnum
];
207 /* Return the GDB type object for the "standard" data type
208 of data in register N. */
211 avr_register_type (struct gdbarch
*gdbarch
, int reg_nr
)
213 if (reg_nr
== AVR_PC_REGNUM
)
214 return builtin_type_uint32
;
215 if (reg_nr
== AVR_SP_REGNUM
)
216 return builtin_type_void_data_ptr
;
218 return builtin_type_uint8
;
221 /* Instruction address checks and convertions. */
224 avr_make_iaddr (CORE_ADDR x
)
226 return ((x
) | AVR_IMEM_START
);
229 /* FIXME: TRoth: Really need to use a larger mask for instructions. Some
230 devices are already up to 128KBytes of flash space.
232 TRoth/2002-04-8: See comment above where AVR_IMEM_START is defined. */
235 avr_convert_iaddr_to_raw (CORE_ADDR x
)
237 return ((x
) & 0xffffffff);
240 /* SRAM address checks and convertions. */
243 avr_make_saddr (CORE_ADDR x
)
245 return ((x
) | AVR_SMEM_START
);
249 avr_convert_saddr_to_raw (CORE_ADDR x
)
251 return ((x
) & 0xffffffff);
254 /* EEPROM address checks and convertions. I don't know if these will ever
255 actually be used, but I've added them just the same. TRoth */
257 /* TRoth/2002-04-08: Commented out for now to allow fix for problem with large
258 programs in the mega128. */
260 /* static CORE_ADDR */
261 /* avr_make_eaddr (CORE_ADDR x) */
263 /* return ((x) | AVR_EMEM_START); */
267 /* avr_eaddr_p (CORE_ADDR x) */
269 /* return (((x) & AVR_MEM_MASK) == AVR_EMEM_START); */
272 /* static CORE_ADDR */
273 /* avr_convert_eaddr_to_raw (CORE_ADDR x) */
275 /* return ((x) & 0xffffffff); */
278 /* Convert from address to pointer and vice-versa. */
281 avr_address_to_pointer (struct type
*type
, gdb_byte
*buf
, CORE_ADDR addr
)
283 /* Is it a code address? */
284 if (TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_FUNC
285 || TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_METHOD
)
287 store_unsigned_integer (buf
, TYPE_LENGTH (type
),
288 avr_convert_iaddr_to_raw (addr
>> 1));
292 /* Strip off any upper segment bits. */
293 store_unsigned_integer (buf
, TYPE_LENGTH (type
),
294 avr_convert_saddr_to_raw (addr
));
299 avr_pointer_to_address (struct type
*type
, const gdb_byte
*buf
)
301 CORE_ADDR addr
= extract_unsigned_integer (buf
, TYPE_LENGTH (type
));
303 /* Is it a code address? */
304 if (TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_FUNC
305 || TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_METHOD
306 || TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type
)))
307 return avr_make_iaddr (addr
<< 1);
309 return avr_make_saddr (addr
);
313 avr_read_pc (struct regcache
*regcache
)
316 regcache_cooked_read_unsigned (regcache
, AVR_PC_REGNUM
, &pc
);
317 return avr_make_iaddr (pc
);
321 avr_write_pc (struct regcache
*regcache
, CORE_ADDR val
)
323 regcache_cooked_write_unsigned (regcache
, AVR_PC_REGNUM
,
324 avr_convert_iaddr_to_raw (val
));
328 avr_scan_arg_moves (int vpc
, unsigned char *prologue
)
332 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
334 insn
= EXTRACT_INSN (&prologue
[vpc
]);
335 if ((insn
& 0xff00) == 0x0100) /* movw rXX, rYY */
337 else if ((insn
& 0xfc00) == 0x2c00) /* mov rXX, rYY */
346 /* Function: avr_scan_prologue
348 This function decodes an AVR function prologue to determine:
349 1) the size of the stack frame
350 2) which registers are saved on it
351 3) the offsets of saved regs
352 This information is stored in the avr_unwind_cache structure.
354 Some devices lack the sbiw instruction, so on those replace this:
360 A typical AVR function prologue with a frame pointer might look like this:
361 push rXX ; saved regs
367 sbiw r28,<LOCALS_SIZE>
368 in __tmp_reg__,__SREG__
371 out __SREG__,__tmp_reg__
374 A typical AVR function prologue without a frame pointer might look like
376 push rXX ; saved regs
379 A main function prologue looks like this:
380 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
381 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
385 A signal handler prologue looks like this:
388 in __tmp_reg__, __SREG__
391 push rXX ; save registers r18:r27, r30:r31
393 push r28 ; save frame pointer
397 sbiw r28, <LOCALS_SIZE>
401 A interrupt handler prologue looks like this:
405 in __tmp_reg__, __SREG__
408 push rXX ; save registers r18:r27, r30:r31
410 push r28 ; save frame pointer
414 sbiw r28, <LOCALS_SIZE>
420 A `-mcall-prologues' prologue looks like this (Note that the megas use a
421 jmp instead of a rjmp, thus the prologue is one word larger since jmp is a
422 32 bit insn and rjmp is a 16 bit insn):
423 ldi r26,lo8(<LOCALS_SIZE>)
424 ldi r27,hi8(<LOCALS_SIZE>)
425 ldi r30,pm_lo8(.L_foo_body)
426 ldi r31,pm_hi8(.L_foo_body)
427 rjmp __prologue_saves__+RRR
430 /* Not really part of a prologue, but still need to scan for it, is when a
431 function prologue moves values passed via registers as arguments to new
432 registers. In this case, all local variables live in registers, so there
433 may be some register saves. This is what it looks like:
437 There could be multiple movw's. If the target doesn't have a movw insn, it
438 will use two mov insns. This could be done after any of the above prologue
442 avr_scan_prologue (CORE_ADDR pc
, struct avr_unwind_cache
*info
)
447 struct minimal_symbol
*msymbol
;
448 unsigned char prologue
[AVR_MAX_PROLOGUE_SIZE
];
451 /* FIXME: TRoth/2003-06-11: This could be made more efficient by only
452 reading in the bytes of the prologue. The problem is that the figuring
453 out where the end of the prologue is is a bit difficult. The old code
454 tried to do that, but failed quite often. */
455 read_memory (pc
, prologue
, AVR_MAX_PROLOGUE_SIZE
);
457 /* Scanning main()'s prologue
458 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
459 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
466 unsigned char img
[] = {
467 0xde, 0xbf, /* out __SP_H__,r29 */
468 0xcd, 0xbf /* out __SP_L__,r28 */
471 insn
= EXTRACT_INSN (&prologue
[vpc
]);
472 /* ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>) */
473 if ((insn
& 0xf0f0) == 0xe0c0)
475 locals
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
476 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
477 /* ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>) */
478 if ((insn
& 0xf0f0) == 0xe0d0)
480 locals
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
481 if (memcmp (prologue
+ vpc
+ 4, img
, sizeof (img
)) == 0)
483 info
->prologue_type
= AVR_PROLOGUE_MAIN
;
491 /* Scanning `-mcall-prologues' prologue
492 Classic prologue is 10 bytes, mega prologue is a 12 bytes long */
494 while (1) /* Using a while to avoid many goto's */
501 insn
= EXTRACT_INSN (&prologue
[vpc
]);
502 /* ldi r26,<LOCALS_SIZE> */
503 if ((insn
& 0xf0f0) != 0xe0a0)
505 loc_size
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
508 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
509 /* ldi r27,<LOCALS_SIZE> / 256 */
510 if ((insn
& 0xf0f0) != 0xe0b0)
512 loc_size
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
515 insn
= EXTRACT_INSN (&prologue
[vpc
+ 4]);
516 /* ldi r30,pm_lo8(.L_foo_body) */
517 if ((insn
& 0xf0f0) != 0xe0e0)
519 body_addr
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
522 insn
= EXTRACT_INSN (&prologue
[vpc
+ 6]);
523 /* ldi r31,pm_hi8(.L_foo_body) */
524 if ((insn
& 0xf0f0) != 0xe0f0)
526 body_addr
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
529 msymbol
= lookup_minimal_symbol ("__prologue_saves__", NULL
, NULL
);
533 insn
= EXTRACT_INSN (&prologue
[vpc
+ 8]);
534 /* rjmp __prologue_saves__+RRR */
535 if ((insn
& 0xf000) == 0xc000)
537 /* Extract PC relative offset from RJMP */
538 i
= (insn
& 0xfff) | (insn
& 0x800 ? (-1 ^ 0xfff) : 0);
539 /* Convert offset to byte addressable mode */
541 /* Destination address */
544 if (body_addr
!= (pc
+ 10)/2)
549 else if ((insn
& 0xfe0e) == 0x940c)
551 /* Extract absolute PC address from JMP */
552 i
= (((insn
& 0x1) | ((insn
& 0x1f0) >> 3) << 16)
553 | (EXTRACT_INSN (&prologue
[vpc
+ 10]) & 0xffff));
554 /* Convert address to byte addressable mode */
557 if (body_addr
!= (pc
+ 12)/2)
565 /* Resolve offset (in words) from __prologue_saves__ symbol.
566 Which is a pushes count in `-mcall-prologues' mode */
567 num_pushes
= AVR_MAX_PUSHES
- (i
- SYMBOL_VALUE_ADDRESS (msymbol
)) / 2;
569 if (num_pushes
> AVR_MAX_PUSHES
)
571 fprintf_unfiltered (gdb_stderr
, _("Num pushes too large: %d\n"),
580 info
->saved_regs
[AVR_FP_REGNUM
+ 1].addr
= num_pushes
;
582 info
->saved_regs
[AVR_FP_REGNUM
].addr
= num_pushes
- 1;
585 for (from
= AVR_LAST_PUSHED_REGNUM
+ 1 - (num_pushes
- 2);
586 from
<= AVR_LAST_PUSHED_REGNUM
; ++from
)
587 info
->saved_regs
[from
].addr
= ++i
;
589 info
->size
= loc_size
+ num_pushes
;
590 info
->prologue_type
= AVR_PROLOGUE_CALL
;
592 return pc
+ pc_offset
;
595 /* Scan for the beginning of the prologue for an interrupt or signal
596 function. Note that we have to set the prologue type here since the
597 third stage of the prologue may not be present (e.g. no saved registered
598 or changing of the SP register). */
602 unsigned char img
[] = {
603 0x78, 0x94, /* sei */
604 0x1f, 0x92, /* push r1 */
605 0x0f, 0x92, /* push r0 */
606 0x0f, 0xb6, /* in r0,0x3f SREG */
607 0x0f, 0x92, /* push r0 */
608 0x11, 0x24 /* clr r1 */
610 if (memcmp (prologue
, img
, sizeof (img
)) == 0)
612 info
->prologue_type
= AVR_PROLOGUE_INTR
;
614 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
615 info
->saved_regs
[0].addr
= 2;
616 info
->saved_regs
[1].addr
= 1;
619 else if (memcmp (img
+ 2, prologue
, sizeof (img
) - 2) == 0)
621 info
->prologue_type
= AVR_PROLOGUE_SIG
;
622 vpc
+= sizeof (img
) - 2;
623 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
624 info
->saved_regs
[0].addr
= 2;
625 info
->saved_regs
[1].addr
= 1;
630 /* First stage of the prologue scanning.
631 Scan pushes (saved registers) */
633 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
635 insn
= EXTRACT_INSN (&prologue
[vpc
]);
636 if ((insn
& 0xfe0f) == 0x920f) /* push rXX */
638 /* Bits 4-9 contain a mask for registers R0-R32. */
639 int regno
= (insn
& 0x1f0) >> 4;
641 info
->saved_regs
[regno
].addr
= info
->size
;
648 if (vpc
>= AVR_MAX_PROLOGUE_SIZE
)
649 fprintf_unfiltered (gdb_stderr
,
650 _("Hit end of prologue while scanning pushes\n"));
652 /* Second stage of the prologue scanning.
657 if (scan_stage
== 1 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
659 unsigned char img
[] = {
660 0xcd, 0xb7, /* in r28,__SP_L__ */
661 0xde, 0xb7 /* in r29,__SP_H__ */
663 unsigned short insn1
;
665 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
672 /* Third stage of the prologue scanning. (Really two stages)
674 sbiw r28,XX or subi r28,lo8(XX)
676 in __tmp_reg__,__SREG__
679 out __SREG__,__tmp_reg__
682 if (scan_stage
== 2 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
685 unsigned char img
[] = {
686 0x0f, 0xb6, /* in r0,0x3f */
687 0xf8, 0x94, /* cli */
688 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
689 0x0f, 0xbe, /* out 0x3f,r0 ; SREG */
690 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
692 unsigned char img_sig
[] = {
693 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
694 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
696 unsigned char img_int
[] = {
697 0xf8, 0x94, /* cli */
698 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
699 0x78, 0x94, /* sei */
700 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
703 insn
= EXTRACT_INSN (&prologue
[vpc
]);
705 if ((insn
& 0xff30) == 0x9720) /* sbiw r28,XXX */
706 locals_size
= (insn
& 0xf) | ((insn
& 0xc0) >> 2);
707 else if ((insn
& 0xf0f0) == 0x50c0) /* subi r28,lo8(XX) */
709 locals_size
= (insn
& 0xf) | ((insn
& 0xf00) >> 4);
710 insn
= EXTRACT_INSN (&prologue
[vpc
]);
712 locals_size
+= ((insn
& 0xf) | ((insn
& 0xf00) >> 4) << 8);
717 /* Scan the last part of the prologue. May not be present for interrupt
718 or signal handler functions, which is why we set the prologue type
719 when we saw the beginning of the prologue previously. */
721 if (memcmp (prologue
+ vpc
, img_sig
, sizeof (img_sig
)) == 0)
723 vpc
+= sizeof (img_sig
);
725 else if (memcmp (prologue
+ vpc
, img_int
, sizeof (img_int
)) == 0)
727 vpc
+= sizeof (img_int
);
729 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
731 info
->prologue_type
= AVR_PROLOGUE_NORMAL
;
735 info
->size
+= locals_size
;
737 return pc
+ avr_scan_arg_moves (vpc
, prologue
);
740 /* If we got this far, we could not scan the prologue, so just return the pc
741 of the frame plus an adjustment for argument move insns. */
743 return pc
+ avr_scan_arg_moves (vpc
, prologue
);;
747 avr_skip_prologue (CORE_ADDR pc
)
749 CORE_ADDR func_addr
, func_end
;
750 CORE_ADDR prologue_end
= pc
;
752 /* See what the symbol table says */
754 if (find_pc_partial_function (pc
, NULL
, &func_addr
, &func_end
))
756 struct symtab_and_line sal
;
757 struct avr_unwind_cache info
= {0};
758 struct trad_frame_saved_reg saved_regs
[AVR_NUM_REGS
];
760 info
.saved_regs
= saved_regs
;
762 /* Need to run the prologue scanner to figure out if the function has a
763 prologue and possibly skip over moving arguments passed via registers
764 to other registers. */
766 prologue_end
= avr_scan_prologue (pc
, &info
);
768 if (info
.prologue_type
== AVR_PROLOGUE_NONE
)
772 sal
= find_pc_line (func_addr
, 0);
774 if (sal
.line
!= 0 && sal
.end
< func_end
)
779 /* Either we didn't find the start of this function (nothing we can do),
780 or there's no line info, or the line after the prologue is after
781 the end of the function (there probably isn't a prologue). */
786 /* Not all avr devices support the BREAK insn. Those that don't should treat
787 it as a NOP. Thus, it should be ok. Since the avr is currently a remote
788 only target, this shouldn't be a problem (I hope). TRoth/2003-05-14 */
790 static const unsigned char *
791 avr_breakpoint_from_pc (CORE_ADDR
* pcptr
, int *lenptr
)
793 static unsigned char avr_break_insn
[] = { 0x98, 0x95 };
794 *lenptr
= sizeof (avr_break_insn
);
795 return avr_break_insn
;
798 /* Given a return value in `regbuf' with a type `valtype',
799 extract and copy its value into `valbuf'.
801 Return values are always passed via registers r25:r24:... */
804 avr_extract_return_value (struct type
*type
, struct regcache
*regcache
,
810 if (TYPE_LENGTH (type
) == 1)
812 regcache_cooked_read_unsigned (regcache
, 24, &c
);
813 store_unsigned_integer (valbuf
, 1, c
);
818 /* The MSB of the return value is always in r25, calculate which
819 register holds the LSB. */
820 int lsb_reg
= 25 - TYPE_LENGTH (type
) + 1;
822 for (i
=0; i
< TYPE_LENGTH (type
); i
++)
824 regcache_cooked_read (regcache
, lsb_reg
+ i
,
825 (bfd_byte
*) valbuf
+ i
);
830 /* Put here the code to store, into fi->saved_regs, the addresses of
831 the saved registers of frame described by FRAME_INFO. This
832 includes special registers such as pc and fp saved in special ways
833 in the stack frame. sp is even more special: the address we return
834 for it IS the sp for the next frame. */
836 struct avr_unwind_cache
*
837 avr_frame_unwind_cache (struct frame_info
*next_frame
,
838 void **this_prologue_cache
)
843 struct avr_unwind_cache
*info
;
846 if ((*this_prologue_cache
))
847 return (*this_prologue_cache
);
849 info
= FRAME_OBSTACK_ZALLOC (struct avr_unwind_cache
);
850 (*this_prologue_cache
) = info
;
851 info
->saved_regs
= trad_frame_alloc_saved_regs (next_frame
);
854 info
->prologue_type
= AVR_PROLOGUE_NONE
;
856 pc
= frame_func_unwind (next_frame
, NORMAL_FRAME
);
858 if ((pc
> 0) && (pc
< frame_pc_unwind (next_frame
)))
859 avr_scan_prologue (pc
, info
);
861 if ((info
->prologue_type
!= AVR_PROLOGUE_NONE
)
862 && (info
->prologue_type
!= AVR_PROLOGUE_MAIN
))
864 ULONGEST high_base
; /* High byte of FP */
866 /* The SP was moved to the FP. This indicates that a new frame
867 was created. Get THIS frame's FP value by unwinding it from
869 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
, &this_base
);
870 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
+1, &high_base
);
871 this_base
+= (high_base
<< 8);
873 /* The FP points at the last saved register. Adjust the FP back
874 to before the first saved register giving the SP. */
875 prev_sp
= this_base
+ info
->size
;
879 /* Assume that the FP is this frame's SP but with that pushed
880 stack space added back. */
881 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &this_base
);
882 prev_sp
= this_base
+ info
->size
;
885 /* Add 1 here to adjust for the post-decrement nature of the push
887 info
->prev_sp
= avr_make_saddr (prev_sp
+1);
889 info
->base
= avr_make_saddr (this_base
);
891 /* Adjust all the saved registers so that they contain addresses and not
893 for (i
= 0; i
< gdbarch_num_regs (current_gdbarch
) - 1; i
++)
894 if (info
->saved_regs
[i
].addr
)
896 info
->saved_regs
[i
].addr
= (info
->prev_sp
- info
->saved_regs
[i
].addr
);
899 /* Except for the main and startup code, the return PC is always saved on
900 the stack and is at the base of the frame. */
902 if (info
->prologue_type
!= AVR_PROLOGUE_MAIN
)
904 info
->saved_regs
[AVR_PC_REGNUM
].addr
= info
->prev_sp
;
907 /* The previous frame's SP needed to be computed. Save the computed
909 trad_frame_set_value (info
->saved_regs
, AVR_SP_REGNUM
, info
->prev_sp
+1);
915 avr_unwind_pc (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
919 frame_unwind_unsigned_register (next_frame
, AVR_PC_REGNUM
, &pc
);
921 return avr_make_iaddr (pc
);
925 avr_unwind_sp (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
929 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &sp
);
931 return avr_make_saddr (sp
);
934 /* Given a GDB frame, determine the address of the calling function's
935 frame. This will be used to create a new GDB frame struct. */
938 avr_frame_this_id (struct frame_info
*next_frame
,
939 void **this_prologue_cache
,
940 struct frame_id
*this_id
)
942 struct avr_unwind_cache
*info
943 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
948 /* The FUNC is easy. */
949 func
= frame_func_unwind (next_frame
, NORMAL_FRAME
);
951 /* Hopefully the prologue analysis either correctly determined the
952 frame's base (which is the SP from the previous frame), or set
953 that base to "NULL". */
954 base
= info
->prev_sp
;
958 id
= frame_id_build (base
, func
);
963 avr_frame_prev_register (struct frame_info
*next_frame
,
964 void **this_prologue_cache
,
965 int regnum
, int *optimizedp
,
966 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
967 int *realnump
, gdb_byte
*bufferp
)
969 struct avr_unwind_cache
*info
970 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
972 if (regnum
== AVR_PC_REGNUM
)
974 if (trad_frame_addr_p (info
->saved_regs
, regnum
))
977 *lvalp
= lval_memory
;
978 *addrp
= info
->saved_regs
[regnum
].addr
;
982 /* Reading the return PC from the PC register is slightly
983 abnormal. register_size(AVR_PC_REGNUM) says it is 4 bytes,
984 but in reality, only two bytes (3 in upcoming mega256) are
987 Also, note that the value on the stack is an addr to a word
988 not a byte, so we will need to multiply it by two at some
991 And to confuse matters even more, the return address stored
992 on the stack is in big endian byte order, even though most
993 everything else about the avr is little endian. Ick! */
995 /* FIXME: number of bytes read here will need updated for the
996 mega256 when it is available. */
1000 unsigned char buf
[2];
1002 read_memory (info
->saved_regs
[regnum
].addr
, buf
, 2);
1004 /* Convert the PC read from memory as a big-endian to
1005 little-endian order. */
1010 pc
= (extract_unsigned_integer (buf
, 2) * 2);
1011 store_unsigned_integer (bufferp
,
1012 register_size (current_gdbarch
, regnum
),
1018 trad_frame_get_prev_register (next_frame
, info
->saved_regs
, regnum
,
1019 optimizedp
, lvalp
, addrp
, realnump
, bufferp
);
1022 static const struct frame_unwind avr_frame_unwind
= {
1025 avr_frame_prev_register
1028 const struct frame_unwind
*
1029 avr_frame_sniffer (struct frame_info
*next_frame
)
1031 return &avr_frame_unwind
;
1035 avr_frame_base_address (struct frame_info
*next_frame
, void **this_cache
)
1037 struct avr_unwind_cache
*info
1038 = avr_frame_unwind_cache (next_frame
, this_cache
);
1043 static const struct frame_base avr_frame_base
= {
1045 avr_frame_base_address
,
1046 avr_frame_base_address
,
1047 avr_frame_base_address
1050 /* Assuming NEXT_FRAME->prev is a dummy, return the frame ID of that
1051 dummy frame. The frame ID's base needs to match the TOS value
1052 saved by save_dummy_frame_tos(), and the PC match the dummy frame's
1055 static struct frame_id
1056 avr_unwind_dummy_id (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
1060 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &base
);
1061 return frame_id_build (avr_make_saddr (base
), frame_pc_unwind (next_frame
));
1064 /* When arguments must be pushed onto the stack, they go on in reverse
1065 order. The below implements a FILO (stack) to do this. */
1070 struct stack_item
*prev
;
1074 static struct stack_item
*
1075 push_stack_item (struct stack_item
*prev
, const bfd_byte
*contents
, int len
)
1077 struct stack_item
*si
;
1078 si
= xmalloc (sizeof (struct stack_item
));
1079 si
->data
= xmalloc (len
);
1082 memcpy (si
->data
, contents
, len
);
1086 static struct stack_item
*pop_stack_item (struct stack_item
*si
);
1087 static struct stack_item
*
1088 pop_stack_item (struct stack_item
*si
)
1090 struct stack_item
*dead
= si
;
1097 /* Setup the function arguments for calling a function in the inferior.
1099 On the AVR architecture, there are 18 registers (R25 to R8) which are
1100 dedicated for passing function arguments. Up to the first 18 arguments
1101 (depending on size) may go into these registers. The rest go on the stack.
1103 All arguments are aligned to start in even-numbered registers (odd-sized
1104 arguments, including char, have one free register above them). For example,
1105 an int in arg1 and a char in arg2 would be passed as such:
1110 Arguments that are larger than 2 bytes will be split between two or more
1111 registers as available, but will NOT be split between a register and the
1112 stack. Arguments that go onto the stack are pushed last arg first (this is
1113 similar to the d10v). */
1115 /* NOTE: TRoth/2003-06-17: The rest of this comment is old looks to be
1118 An exceptional case exists for struct arguments (and possibly other
1119 aggregates such as arrays) -- if the size is larger than WORDSIZE bytes but
1120 not a multiple of WORDSIZE bytes. In this case the argument is never split
1121 between the registers and the stack, but instead is copied in its entirety
1122 onto the stack, AND also copied into as many registers as there is room
1123 for. In other words, space in registers permitting, two copies of the same
1124 argument are passed in. As far as I can tell, only the one on the stack is
1125 used, although that may be a function of the level of compiler
1126 optimization. I suspect this is a compiler bug. Arguments of these odd
1127 sizes are left-justified within the word (as opposed to arguments smaller
1128 than WORDSIZE bytes, which are right-justified).
1130 If the function is to return an aggregate type such as a struct, the caller
1131 must allocate space into which the callee will copy the return value. In
1132 this case, a pointer to the return value location is passed into the callee
1133 in register R0, which displaces one of the other arguments passed in via
1134 registers R0 to R2. */
1137 avr_push_dummy_call (struct gdbarch
*gdbarch
, struct value
*function
,
1138 struct regcache
*regcache
, CORE_ADDR bp_addr
,
1139 int nargs
, struct value
**args
, CORE_ADDR sp
,
1140 int struct_return
, CORE_ADDR struct_addr
)
1143 unsigned char buf
[2];
1144 CORE_ADDR return_pc
= avr_convert_iaddr_to_raw (bp_addr
);
1145 int regnum
= AVR_ARGN_REGNUM
;
1146 struct stack_item
*si
= NULL
;
1149 /* FIXME: TRoth/2003-06-18: Not sure what to do when returning a struct. */
1152 fprintf_unfiltered (gdb_stderr
, "struct_return: 0x%lx\n", struct_addr
);
1153 regcache_cooked_write_unsigned (regcache
, argreg
--, struct_addr
& 0xff);
1154 regcache_cooked_write_unsigned (regcache
, argreg
--, (struct_addr
>>8) & 0xff);
1158 for (i
= 0; i
< nargs
; i
++)
1162 struct value
*arg
= args
[i
];
1163 struct type
*type
= check_typedef (value_type (arg
));
1164 const bfd_byte
*contents
= value_contents (arg
);
1165 int len
= TYPE_LENGTH (type
);
1167 /* Calculate the potential last register needed. */
1168 last_regnum
= regnum
- (len
+ (len
& 1));
1170 /* If there are registers available, use them. Once we start putting
1171 stuff on the stack, all subsequent args go on stack. */
1172 if ((si
== NULL
) && (last_regnum
>= 8))
1176 /* Skip a register for odd length args. */
1180 val
= extract_unsigned_integer (contents
, len
);
1181 for (j
=0; j
<len
; j
++)
1183 regcache_cooked_write_unsigned (regcache
, regnum
--,
1184 val
>> (8*(len
-j
-1)));
1187 /* No registers available, push the args onto the stack. */
1190 /* From here on, we don't care about regnum. */
1191 si
= push_stack_item (si
, contents
, len
);
1195 /* Push args onto the stack. */
1199 /* Add 1 to sp here to account for post decr nature of pushes. */
1200 write_memory (sp
+1, si
->data
, si
->len
);
1201 si
= pop_stack_item (si
);
1204 /* Set the return address. For the avr, the return address is the BP_ADDR.
1205 Need to push the return address onto the stack noting that it needs to be
1206 in big-endian order on the stack. */
1207 buf
[0] = (return_pc
>> 8) & 0xff;
1208 buf
[1] = return_pc
& 0xff;
1211 write_memory (sp
+1, buf
, 2); /* Add one since pushes are post decr ops. */
1213 /* Finally, update the SP register. */
1214 regcache_cooked_write_unsigned (regcache
, AVR_SP_REGNUM
,
1215 avr_convert_saddr_to_raw (sp
));
1220 /* Initialize the gdbarch structure for the AVR's. */
1222 static struct gdbarch
*
1223 avr_gdbarch_init (struct gdbarch_info info
, struct gdbarch_list
*arches
)
1225 struct gdbarch
*gdbarch
;
1226 struct gdbarch_tdep
*tdep
;
1228 /* Find a candidate among the list of pre-declared architectures. */
1229 arches
= gdbarch_list_lookup_by_info (arches
, &info
);
1231 return arches
->gdbarch
;
1233 /* None found, create a new architecture from the information provided. */
1234 tdep
= XMALLOC (struct gdbarch_tdep
);
1235 gdbarch
= gdbarch_alloc (&info
, tdep
);
1237 /* If we ever need to differentiate the device types, do it here. */
1238 switch (info
.bfd_arch_info
->mach
)
1248 set_gdbarch_short_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1249 set_gdbarch_int_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1250 set_gdbarch_long_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1251 set_gdbarch_long_long_bit (gdbarch
, 8 * TARGET_CHAR_BIT
);
1252 set_gdbarch_ptr_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1253 set_gdbarch_addr_bit (gdbarch
, 32);
1255 set_gdbarch_float_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1256 set_gdbarch_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1257 set_gdbarch_long_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1259 set_gdbarch_float_format (gdbarch
, floatformats_ieee_single
);
1260 set_gdbarch_double_format (gdbarch
, floatformats_ieee_single
);
1261 set_gdbarch_long_double_format (gdbarch
, floatformats_ieee_single
);
1263 set_gdbarch_read_pc (gdbarch
, avr_read_pc
);
1264 set_gdbarch_write_pc (gdbarch
, avr_write_pc
);
1266 set_gdbarch_num_regs (gdbarch
, AVR_NUM_REGS
);
1268 set_gdbarch_sp_regnum (gdbarch
, AVR_SP_REGNUM
);
1269 set_gdbarch_pc_regnum (gdbarch
, AVR_PC_REGNUM
);
1271 set_gdbarch_register_name (gdbarch
, avr_register_name
);
1272 set_gdbarch_register_type (gdbarch
, avr_register_type
);
1274 set_gdbarch_extract_return_value (gdbarch
, avr_extract_return_value
);
1275 set_gdbarch_print_insn (gdbarch
, print_insn_avr
);
1277 set_gdbarch_push_dummy_call (gdbarch
, avr_push_dummy_call
);
1279 set_gdbarch_address_to_pointer (gdbarch
, avr_address_to_pointer
);
1280 set_gdbarch_pointer_to_address (gdbarch
, avr_pointer_to_address
);
1282 set_gdbarch_skip_prologue (gdbarch
, avr_skip_prologue
);
1283 set_gdbarch_inner_than (gdbarch
, core_addr_lessthan
);
1285 set_gdbarch_breakpoint_from_pc (gdbarch
, avr_breakpoint_from_pc
);
1287 frame_unwind_append_sniffer (gdbarch
, avr_frame_sniffer
);
1288 frame_base_set_default (gdbarch
, &avr_frame_base
);
1290 set_gdbarch_unwind_dummy_id (gdbarch
, avr_unwind_dummy_id
);
1292 set_gdbarch_unwind_pc (gdbarch
, avr_unwind_pc
);
1293 set_gdbarch_unwind_sp (gdbarch
, avr_unwind_sp
);
1298 /* Send a query request to the avr remote target asking for values of the io
1299 registers. If args parameter is not NULL, then the user has requested info
1300 on a specific io register [This still needs implemented and is ignored for
1301 now]. The query string should be one of these forms:
1303 "Ravr.io_reg" -> reply is "NN" number of io registers
1305 "Ravr.io_reg:addr,len" where addr is first register and len is number of
1306 registers to be read. The reply should be "<NAME>,VV;" for each io register
1307 where, <NAME> is a string, and VV is the hex value of the register.
1309 All io registers are 8-bit. */
1312 avr_io_reg_read_command (char *args
, int from_tty
)
1318 unsigned int nreg
= 0;
1322 /* Find out how many io registers the target has. */
1323 bufsiz
= target_read_alloc (¤t_target
, TARGET_OBJECT_AVR
,
1324 "avr.io_reg", &buf
);
1328 fprintf_unfiltered (gdb_stderr
,
1329 _("ERR: info io_registers NOT supported "
1330 "by current target\n"));
1334 if (sscanf (buf
, "%x", &nreg
) != 1)
1336 fprintf_unfiltered (gdb_stderr
,
1337 _("Error fetching number of io registers\n"));
1344 reinitialize_more_filter ();
1346 printf_unfiltered (_("Target has %u io registers:\n\n"), nreg
);
1348 /* only fetch up to 8 registers at a time to keep the buffer small */
1351 for (i
= 0; i
< nreg
; i
+= step
)
1353 /* how many registers this round? */
1356 j
= nreg
- i
; /* last block is less than 8 registers */
1358 snprintf (query
, sizeof (query
) - 1, "avr.io_reg:%x,%x", i
, j
);
1359 bufsiz
= target_read_alloc (¤t_target
, TARGET_OBJECT_AVR
,
1363 for (k
= i
; k
< (i
+ j
); k
++)
1365 if (sscanf (p
, "%[^,],%x;", query
, &val
) == 2)
1367 printf_filtered ("[%02x] %-15s : %02x\n", k
, query
, val
);
1368 while ((*p
!= ';') && (*p
!= '\0'))
1370 p
++; /* skip over ';' */
1380 extern initialize_file_ftype _initialize_avr_tdep
; /* -Wmissing-prototypes */
1383 _initialize_avr_tdep (void)
1385 register_gdbarch_init (bfd_arch_avr
, avr_gdbarch_init
);
1387 /* Add a new command to allow the user to query the avr remote target for
1388 the values of the io space registers in a saner way than just using
1391 /* FIXME: TRoth/2002-02-18: This should probably be changed to 'info avr
1392 io_registers' to signify it is not available on other platforms. */
1394 add_cmd ("io_registers", class_info
, avr_io_reg_read_command
,
1395 _("query remote avr target for io space register values"),