1 /* Target-dependent code for Atmel AVR, for GDB.
2 Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
3 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
22 /* Contributed by Theodore A. Roth, troth@openavr.org */
24 /* Portions of this file were taken from the original gdb-4.18 patch developed
25 by Denis Chertykov, denisc@overta.ru */
29 #include "frame-unwind.h"
30 #include "frame-base.h"
31 #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
);
230 avr_iaddr_p (CORE_ADDR x
)
232 return (((x
) & AVR_MEM_MASK
) == AVR_IMEM_START
);
235 /* FIXME: TRoth: Really need to use a larger mask for instructions. Some
236 devices are already up to 128KBytes of flash space.
238 TRoth/2002-04-8: See comment above where AVR_IMEM_START is defined. */
241 avr_convert_iaddr_to_raw (CORE_ADDR x
)
243 return ((x
) & 0xffffffff);
246 /* SRAM address checks and convertions. */
249 avr_make_saddr (CORE_ADDR x
)
251 return ((x
) | AVR_SMEM_START
);
255 avr_saddr_p (CORE_ADDR x
)
257 return (((x
) & AVR_MEM_MASK
) == AVR_SMEM_START
);
261 avr_convert_saddr_to_raw (CORE_ADDR x
)
263 return ((x
) & 0xffffffff);
266 /* EEPROM address checks and convertions. I don't know if these will ever
267 actually be used, but I've added them just the same. TRoth */
269 /* TRoth/2002-04-08: Commented out for now to allow fix for problem with large
270 programs in the mega128. */
272 /* static CORE_ADDR */
273 /* avr_make_eaddr (CORE_ADDR x) */
275 /* return ((x) | AVR_EMEM_START); */
279 /* avr_eaddr_p (CORE_ADDR x) */
281 /* return (((x) & AVR_MEM_MASK) == AVR_EMEM_START); */
284 /* static CORE_ADDR */
285 /* avr_convert_eaddr_to_raw (CORE_ADDR x) */
287 /* return ((x) & 0xffffffff); */
290 /* Convert from address to pointer and vice-versa. */
293 avr_address_to_pointer (struct type
*type
, void *buf
, CORE_ADDR addr
)
295 /* Is it a code address? */
296 if (TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_FUNC
297 || TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_METHOD
)
299 store_unsigned_integer (buf
, TYPE_LENGTH (type
),
300 avr_convert_iaddr_to_raw (addr
>> 1));
304 /* Strip off any upper segment bits. */
305 store_unsigned_integer (buf
, TYPE_LENGTH (type
),
306 avr_convert_saddr_to_raw (addr
));
311 avr_pointer_to_address (struct type
*type
, const void *buf
)
313 CORE_ADDR addr
= extract_unsigned_integer (buf
, TYPE_LENGTH (type
));
315 /* Is it a code address? */
316 if (TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_FUNC
317 || TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_METHOD
318 || TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type
)))
319 return avr_make_iaddr (addr
<< 1);
321 return avr_make_saddr (addr
);
325 avr_read_pc (ptid_t ptid
)
331 save_ptid
= inferior_ptid
;
332 inferior_ptid
= ptid
;
333 regcache_cooked_read_unsigned (current_regcache
, AVR_PC_REGNUM
, &pc
);
334 inferior_ptid
= save_ptid
;
335 retval
= avr_make_iaddr (pc
);
340 avr_write_pc (CORE_ADDR val
, ptid_t ptid
)
344 save_ptid
= inferior_ptid
;
345 inferior_ptid
= ptid
;
346 write_register (AVR_PC_REGNUM
, avr_convert_iaddr_to_raw (val
));
347 inferior_ptid
= save_ptid
;
355 regcache_cooked_read_unsigned (current_regcache
, AVR_SP_REGNUM
, &sp
);
356 return (avr_make_saddr (sp
));
360 avr_scan_arg_moves (int vpc
, unsigned char *prologue
)
364 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
366 insn
= EXTRACT_INSN (&prologue
[vpc
]);
367 if ((insn
& 0xff00) == 0x0100) /* movw rXX, rYY */
369 else if ((insn
& 0xfc00) == 0x2c00) /* mov rXX, rYY */
378 /* Function: avr_scan_prologue
380 This function decodes an AVR function prologue to determine:
381 1) the size of the stack frame
382 2) which registers are saved on it
383 3) the offsets of saved regs
384 This information is stored in the avr_unwind_cache structure.
386 Some devices lack the sbiw instruction, so on those replace this:
392 A typical AVR function prologue with a frame pointer might look like this:
393 push rXX ; saved regs
399 sbiw r28,<LOCALS_SIZE>
400 in __tmp_reg__,__SREG__
403 out __SREG__,__tmp_reg__
406 A typical AVR function prologue without a frame pointer might look like
408 push rXX ; saved regs
411 A main function prologue looks like this:
412 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
413 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
417 A signal handler prologue looks like this:
420 in __tmp_reg__, __SREG__
423 push rXX ; save registers r18:r27, r30:r31
425 push r28 ; save frame pointer
429 sbiw r28, <LOCALS_SIZE>
433 A interrupt handler prologue looks like this:
437 in __tmp_reg__, __SREG__
440 push rXX ; save registers r18:r27, r30:r31
442 push r28 ; save frame pointer
446 sbiw r28, <LOCALS_SIZE>
452 A `-mcall-prologues' prologue looks like this (Note that the megas use a
453 jmp instead of a rjmp, thus the prologue is one word larger since jmp is a
454 32 bit insn and rjmp is a 16 bit insn):
455 ldi r26,lo8(<LOCALS_SIZE>)
456 ldi r27,hi8(<LOCALS_SIZE>)
457 ldi r30,pm_lo8(.L_foo_body)
458 ldi r31,pm_hi8(.L_foo_body)
459 rjmp __prologue_saves__+RRR
462 /* Not really part of a prologue, but still need to scan for it, is when a
463 function prologue moves values passed via registers as arguments to new
464 registers. In this case, all local variables live in registers, so there
465 may be some register saves. This is what it looks like:
469 There could be multiple movw's. If the target doesn't have a movw insn, it
470 will use two mov insns. This could be done after any of the above prologue
474 avr_scan_prologue (CORE_ADDR pc
, struct avr_unwind_cache
*info
)
479 struct minimal_symbol
*msymbol
;
480 unsigned char prologue
[AVR_MAX_PROLOGUE_SIZE
];
483 /* FIXME: TRoth/2003-06-11: This could be made more efficient by only
484 reading in the bytes of the prologue. The problem is that the figuring
485 out where the end of the prologue is is a bit difficult. The old code
486 tried to do that, but failed quite often. */
487 read_memory (pc
, prologue
, AVR_MAX_PROLOGUE_SIZE
);
489 /* Scanning main()'s prologue
490 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
491 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
498 unsigned char img
[] = {
499 0xde, 0xbf, /* out __SP_H__,r29 */
500 0xcd, 0xbf /* out __SP_L__,r28 */
503 insn
= EXTRACT_INSN (&prologue
[vpc
]);
504 /* ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>) */
505 if ((insn
& 0xf0f0) == 0xe0c0)
507 locals
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
508 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
509 /* ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>) */
510 if ((insn
& 0xf0f0) == 0xe0d0)
512 locals
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
513 if (memcmp (prologue
+ vpc
+ 4, img
, sizeof (img
)) == 0)
515 info
->prologue_type
= AVR_PROLOGUE_MAIN
;
523 /* Scanning `-mcall-prologues' prologue
524 Classic prologue is 10 bytes, mega prologue is a 12 bytes long */
526 while (1) /* Using a while to avoid many goto's */
533 insn
= EXTRACT_INSN (&prologue
[vpc
]);
534 /* ldi r26,<LOCALS_SIZE> */
535 if ((insn
& 0xf0f0) != 0xe0a0)
537 loc_size
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
540 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
541 /* ldi r27,<LOCALS_SIZE> / 256 */
542 if ((insn
& 0xf0f0) != 0xe0b0)
544 loc_size
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
547 insn
= EXTRACT_INSN (&prologue
[vpc
+ 4]);
548 /* ldi r30,pm_lo8(.L_foo_body) */
549 if ((insn
& 0xf0f0) != 0xe0e0)
551 body_addr
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
554 insn
= EXTRACT_INSN (&prologue
[vpc
+ 6]);
555 /* ldi r31,pm_hi8(.L_foo_body) */
556 if ((insn
& 0xf0f0) != 0xe0f0)
558 body_addr
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
561 msymbol
= lookup_minimal_symbol ("__prologue_saves__", NULL
, NULL
);
565 insn
= EXTRACT_INSN (&prologue
[vpc
+ 8]);
566 /* rjmp __prologue_saves__+RRR */
567 if ((insn
& 0xf000) == 0xc000)
569 /* Extract PC relative offset from RJMP */
570 i
= (insn
& 0xfff) | (insn
& 0x800 ? (-1 ^ 0xfff) : 0);
571 /* Convert offset to byte addressable mode */
573 /* Destination address */
576 if (body_addr
!= (pc
+ 10)/2)
581 else if ((insn
& 0xfe0e) == 0x940c)
583 /* Extract absolute PC address from JMP */
584 i
= (((insn
& 0x1) | ((insn
& 0x1f0) >> 3) << 16)
585 | (EXTRACT_INSN (&prologue
[vpc
+ 10]) & 0xffff));
586 /* Convert address to byte addressable mode */
589 if (body_addr
!= (pc
+ 12)/2)
597 /* Resolve offset (in words) from __prologue_saves__ symbol.
598 Which is a pushes count in `-mcall-prologues' mode */
599 num_pushes
= AVR_MAX_PUSHES
- (i
- SYMBOL_VALUE_ADDRESS (msymbol
)) / 2;
601 if (num_pushes
> AVR_MAX_PUSHES
)
603 fprintf_unfiltered (gdb_stderr
, "Num pushes too large: %d\n",
612 info
->saved_regs
[AVR_FP_REGNUM
+ 1].addr
= num_pushes
;
614 info
->saved_regs
[AVR_FP_REGNUM
].addr
= num_pushes
- 1;
617 for (from
= AVR_LAST_PUSHED_REGNUM
+ 1 - (num_pushes
- 2);
618 from
<= AVR_LAST_PUSHED_REGNUM
; ++from
)
619 info
->saved_regs
[from
].addr
= ++i
;
621 info
->size
= loc_size
+ num_pushes
;
622 info
->prologue_type
= AVR_PROLOGUE_CALL
;
624 return pc
+ pc_offset
;
627 /* Scan for the beginning of the prologue for an interrupt or signal
628 function. Note that we have to set the prologue type here since the
629 third stage of the prologue may not be present (e.g. no saved registered
630 or changing of the SP register). */
634 unsigned char img
[] = {
635 0x78, 0x94, /* sei */
636 0x1f, 0x92, /* push r1 */
637 0x0f, 0x92, /* push r0 */
638 0x0f, 0xb6, /* in r0,0x3f SREG */
639 0x0f, 0x92, /* push r0 */
640 0x11, 0x24 /* clr r1 */
642 if (memcmp (prologue
, img
, sizeof (img
)) == 0)
644 info
->prologue_type
= AVR_PROLOGUE_INTR
;
646 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
647 info
->saved_regs
[0].addr
= 2;
648 info
->saved_regs
[1].addr
= 1;
651 else if (memcmp (img
+ 2, prologue
, sizeof (img
) - 2) == 0)
653 info
->prologue_type
= AVR_PROLOGUE_SIG
;
654 vpc
+= sizeof (img
) - 2;
655 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
656 info
->saved_regs
[0].addr
= 2;
657 info
->saved_regs
[1].addr
= 1;
662 /* First stage of the prologue scanning.
663 Scan pushes (saved registers) */
665 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
667 insn
= EXTRACT_INSN (&prologue
[vpc
]);
668 if ((insn
& 0xfe0f) == 0x920f) /* push rXX */
670 /* Bits 4-9 contain a mask for registers R0-R32. */
671 int regno
= (insn
& 0x1f0) >> 4;
673 info
->saved_regs
[regno
].addr
= info
->size
;
680 if (vpc
>= AVR_MAX_PROLOGUE_SIZE
)
681 fprintf_unfiltered (gdb_stderr
,
682 "Hit end of prologue while scanning pushes\n");
684 /* Second stage of the prologue scanning.
689 if (scan_stage
== 1 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
691 unsigned char img
[] = {
692 0xcd, 0xb7, /* in r28,__SP_L__ */
693 0xde, 0xb7 /* in r29,__SP_H__ */
695 unsigned short insn1
;
697 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
704 /* Third stage of the prologue scanning. (Really two stages)
706 sbiw r28,XX or subi r28,lo8(XX)
708 in __tmp_reg__,__SREG__
711 out __SREG__,__tmp_reg__
714 if (scan_stage
== 2 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
717 unsigned char img
[] = {
718 0x0f, 0xb6, /* in r0,0x3f */
719 0xf8, 0x94, /* cli */
720 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
721 0x0f, 0xbe, /* out 0x3f,r0 ; SREG */
722 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
724 unsigned char img_sig
[] = {
725 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
726 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
728 unsigned char img_int
[] = {
729 0xf8, 0x94, /* cli */
730 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
731 0x78, 0x94, /* sei */
732 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
735 insn
= EXTRACT_INSN (&prologue
[vpc
]);
737 if ((insn
& 0xff30) == 0x9720) /* sbiw r28,XXX */
738 locals_size
= (insn
& 0xf) | ((insn
& 0xc0) >> 2);
739 else if ((insn
& 0xf0f0) == 0x50c0) /* subi r28,lo8(XX) */
741 locals_size
= (insn
& 0xf) | ((insn
& 0xf00) >> 4);
742 insn
= EXTRACT_INSN (&prologue
[vpc
]);
744 locals_size
+= ((insn
& 0xf) | ((insn
& 0xf00) >> 4) << 8);
749 /* Scan the last part of the prologue. May not be present for interrupt
750 or signal handler functions, which is why we set the prologue type
751 when we saw the beginning of the prologue previously. */
753 if (memcmp (prologue
+ vpc
, img_sig
, sizeof (img_sig
)) == 0)
755 vpc
+= sizeof (img_sig
);
757 else if (memcmp (prologue
+ vpc
, img_int
, sizeof (img_int
)) == 0)
759 vpc
+= sizeof (img_int
);
761 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
763 info
->prologue_type
= AVR_PROLOGUE_NORMAL
;
767 info
->size
+= locals_size
;
769 return pc
+ avr_scan_arg_moves (vpc
, prologue
);
772 /* If we got this far, we could not scan the prologue, so just return the pc
773 of the frame plus an adjustment for argument move insns. */
775 return pc
+ avr_scan_arg_moves (vpc
, prologue
);;
779 avr_skip_prologue (CORE_ADDR pc
)
781 CORE_ADDR func_addr
, func_end
;
782 CORE_ADDR prologue_end
= pc
;
784 /* See what the symbol table says */
786 if (find_pc_partial_function (pc
, NULL
, &func_addr
, &func_end
))
788 struct symtab_and_line sal
;
789 struct avr_unwind_cache info
= {0};
790 struct trad_frame_saved_reg saved_regs
[AVR_NUM_REGS
];
792 info
.saved_regs
= saved_regs
;
794 /* Need to run the prologue scanner to figure out if the function has a
795 prologue and possibly skip over moving arguments passed via registers
796 to other registers. */
798 prologue_end
= avr_scan_prologue (pc
, &info
);
800 if (info
.prologue_type
== AVR_PROLOGUE_NONE
)
804 sal
= find_pc_line (func_addr
, 0);
806 if (sal
.line
!= 0 && sal
.end
< func_end
)
811 /* Either we didn't find the start of this function (nothing we can do),
812 or there's no line info, or the line after the prologue is after
813 the end of the function (there probably isn't a prologue). */
818 /* Not all avr devices support the BREAK insn. Those that don't should treat
819 it as a NOP. Thus, it should be ok. Since the avr is currently a remote
820 only target, this shouldn't be a problem (I hope). TRoth/2003-05-14 */
822 static const unsigned char *
823 avr_breakpoint_from_pc (CORE_ADDR
* pcptr
, int *lenptr
)
825 static unsigned char avr_break_insn
[] = { 0x98, 0x95 };
826 *lenptr
= sizeof (avr_break_insn
);
827 return avr_break_insn
;
830 /* Given a return value in `regbuf' with a type `valtype',
831 extract and copy its value into `valbuf'.
833 Return values are always passed via registers r25:r24:... */
836 avr_extract_return_value (struct type
*type
, struct regcache
*regcache
,
842 if (TYPE_LENGTH (type
) == 1)
844 regcache_cooked_read_unsigned (regcache
, 24, &c
);
845 store_unsigned_integer (valbuf
, 1, c
);
850 /* The MSB of the return value is always in r25, calculate which
851 register holds the LSB. */
852 int lsb_reg
= 25 - TYPE_LENGTH (type
) + 1;
854 for (i
=0; i
< TYPE_LENGTH (type
); i
++)
856 regcache_cooked_read (regcache
, lsb_reg
+ i
,
857 (bfd_byte
*) valbuf
+ i
);
862 /* Put here the code to store, into fi->saved_regs, the addresses of
863 the saved registers of frame described by FRAME_INFO. This
864 includes special registers such as pc and fp saved in special ways
865 in the stack frame. sp is even more special: the address we return
866 for it IS the sp for the next frame. */
868 struct avr_unwind_cache
*
869 avr_frame_unwind_cache (struct frame_info
*next_frame
,
870 void **this_prologue_cache
)
875 struct avr_unwind_cache
*info
;
878 if ((*this_prologue_cache
))
879 return (*this_prologue_cache
);
881 info
= FRAME_OBSTACK_ZALLOC (struct avr_unwind_cache
);
882 (*this_prologue_cache
) = info
;
883 info
->saved_regs
= trad_frame_alloc_saved_regs (next_frame
);
886 info
->prologue_type
= AVR_PROLOGUE_NONE
;
888 pc
= frame_func_unwind (next_frame
);
890 if ((pc
> 0) && (pc
< frame_pc_unwind (next_frame
)))
891 avr_scan_prologue (pc
, info
);
893 if ((info
->prologue_type
!= AVR_PROLOGUE_NONE
)
894 && (info
->prologue_type
!= AVR_PROLOGUE_MAIN
))
896 ULONGEST high_base
; /* High byte of FP */
898 /* The SP was moved to the FP. This indicates that a new frame
899 was created. Get THIS frame's FP value by unwinding it from
901 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
, &this_base
);
902 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
+1, &high_base
);
903 this_base
+= (high_base
<< 8);
905 /* The FP points at the last saved register. Adjust the FP back
906 to before the first saved register giving the SP. */
907 prev_sp
= this_base
+ info
->size
;
911 /* Assume that the FP is this frame's SP but with that pushed
912 stack space added back. */
913 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &this_base
);
914 prev_sp
= this_base
+ info
->size
;
917 /* Add 1 here to adjust for the post-decrement nature of the push
919 info
->prev_sp
= avr_make_saddr (prev_sp
+1);
921 info
->base
= avr_make_saddr (this_base
);
923 /* Adjust all the saved registers so that they contain addresses and not
925 for (i
= 0; i
< NUM_REGS
- 1; i
++)
926 if (info
->saved_regs
[i
].addr
)
928 info
->saved_regs
[i
].addr
= (info
->prev_sp
- info
->saved_regs
[i
].addr
);
931 /* Except for the main and startup code, the return PC is always saved on
932 the stack and is at the base of the frame. */
934 if (info
->prologue_type
!= AVR_PROLOGUE_MAIN
)
936 info
->saved_regs
[AVR_PC_REGNUM
].addr
= info
->prev_sp
;
939 /* The previous frame's SP needed to be computed. Save the computed
941 trad_frame_set_value (info
->saved_regs
, AVR_SP_REGNUM
, info
->prev_sp
+1);
947 avr_unwind_pc (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
951 frame_unwind_unsigned_register (next_frame
, AVR_PC_REGNUM
, &pc
);
953 return avr_make_iaddr (pc
);
956 /* Given a GDB frame, determine the address of the calling function's
957 frame. This will be used to create a new GDB frame struct. */
960 avr_frame_this_id (struct frame_info
*next_frame
,
961 void **this_prologue_cache
,
962 struct frame_id
*this_id
)
964 struct avr_unwind_cache
*info
965 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
970 /* The FUNC is easy. */
971 func
= frame_func_unwind (next_frame
);
973 /* This is meant to halt the backtrace at "_start". Make sure we
974 don't halt it at a generic dummy frame. */
975 if (deprecated_inside_entry_file (func
))
978 /* Hopefully the prologue analysis either correctly determined the
979 frame's base (which is the SP from the previous frame), or set
980 that base to "NULL". */
981 base
= info
->prev_sp
;
985 id
= frame_id_build (base
, func
);
987 /* Check that we're not going round in circles with the same frame
988 ID (but avoid applying the test to sentinel frames which do go
989 round in circles). Can't use frame_id_eq() as that doesn't yet
990 compare the frame's PC value. */
991 if (frame_relative_level (next_frame
) >= 0
992 && get_frame_type (next_frame
) != DUMMY_FRAME
993 && frame_id_eq (get_frame_id (next_frame
), id
))
1000 avr_frame_prev_register (struct frame_info
*next_frame
,
1001 void **this_prologue_cache
,
1002 int regnum
, int *optimizedp
,
1003 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
1004 int *realnump
, void *bufferp
)
1006 struct avr_unwind_cache
*info
1007 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
1009 if (regnum
== AVR_PC_REGNUM
)
1011 if (trad_frame_addr_p (info
->saved_regs
, regnum
))
1014 *lvalp
= lval_memory
;
1015 *addrp
= info
->saved_regs
[regnum
].addr
;
1017 if (bufferp
!= NULL
)
1019 /* Reading the return PC from the PC register is slightly
1020 abnormal. register_size(AVR_PC_REGNUM) says it is 4 bytes,
1021 but in reality, only two bytes (3 in upcoming mega256) are
1022 stored on the stack.
1024 Also, note that the value on the stack is an addr to a word
1025 not a byte, so we will need to multiply it by two at some
1028 And to confuse matters even more, the return address stored
1029 on the stack is in big endian byte order, even though most
1030 everything else about the avr is little endian. Ick! */
1032 /* FIXME: number of bytes read here will need updated for the
1033 mega256 when it is available. */
1037 unsigned char buf
[2];
1039 read_memory (info
->saved_regs
[regnum
].addr
, buf
, 2);
1041 /* Convert the PC read from memory as a big-endian to
1042 little-endian order. */
1047 pc
= (extract_unsigned_integer (buf
, 2) * 2);
1048 store_unsigned_integer (bufferp
,
1049 register_size (current_gdbarch
, regnum
),
1055 trad_frame_prev_register (next_frame
, info
->saved_regs
, regnum
,
1056 optimizedp
, lvalp
, addrp
, realnump
, bufferp
);
1059 static const struct frame_unwind avr_frame_unwind
= {
1062 avr_frame_prev_register
1065 const struct frame_unwind
*
1066 avr_frame_sniffer (struct frame_info
*next_frame
)
1068 return &avr_frame_unwind
;
1072 avr_frame_base_address (struct frame_info
*next_frame
, void **this_cache
)
1074 struct avr_unwind_cache
*info
1075 = avr_frame_unwind_cache (next_frame
, this_cache
);
1080 static const struct frame_base avr_frame_base
= {
1082 avr_frame_base_address
,
1083 avr_frame_base_address
,
1084 avr_frame_base_address
1087 /* Assuming NEXT_FRAME->prev is a dummy, return the frame ID of that
1088 dummy frame. The frame ID's base needs to match the TOS value
1089 saved by save_dummy_frame_tos(), and the PC match the dummy frame's
1092 static struct frame_id
1093 avr_unwind_dummy_id (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
1097 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &base
);
1098 return frame_id_build (avr_make_saddr (base
), frame_pc_unwind (next_frame
));
1101 /* When arguments must be pushed onto the stack, they go on in reverse
1102 order. The below implements a FILO (stack) to do this. */
1107 struct stack_item
*prev
;
1111 static struct stack_item
*push_stack_item (struct stack_item
*prev
,
1112 void *contents
, int len
);
1113 static struct stack_item
*
1114 push_stack_item (struct stack_item
*prev
, void *contents
, int len
)
1116 struct stack_item
*si
;
1117 si
= xmalloc (sizeof (struct stack_item
));
1118 si
->data
= xmalloc (len
);
1121 memcpy (si
->data
, contents
, len
);
1125 static struct stack_item
*pop_stack_item (struct stack_item
*si
);
1126 static struct stack_item
*
1127 pop_stack_item (struct stack_item
*si
)
1129 struct stack_item
*dead
= si
;
1136 /* Setup the function arguments for calling a function in the inferior.
1138 On the AVR architecture, there are 18 registers (R25 to R8) which are
1139 dedicated for passing function arguments. Up to the first 18 arguments
1140 (depending on size) may go into these registers. The rest go on the stack.
1142 All arguments are aligned to start in even-numbered registers (odd-sized
1143 arguments, including char, have one free register above them). For example,
1144 an int in arg1 and a char in arg2 would be passed as such:
1149 Arguments that are larger than 2 bytes will be split between two or more
1150 registers as available, but will NOT be split between a register and the
1151 stack. Arguments that go onto the stack are pushed last arg first (this is
1152 similar to the d10v). */
1154 /* NOTE: TRoth/2003-06-17: The rest of this comment is old looks to be
1157 An exceptional case exists for struct arguments (and possibly other
1158 aggregates such as arrays) -- if the size is larger than WORDSIZE bytes but
1159 not a multiple of WORDSIZE bytes. In this case the argument is never split
1160 between the registers and the stack, but instead is copied in its entirety
1161 onto the stack, AND also copied into as many registers as there is room
1162 for. In other words, space in registers permitting, two copies of the same
1163 argument are passed in. As far as I can tell, only the one on the stack is
1164 used, although that may be a function of the level of compiler
1165 optimization. I suspect this is a compiler bug. Arguments of these odd
1166 sizes are left-justified within the word (as opposed to arguments smaller
1167 than WORDSIZE bytes, which are right-justified).
1169 If the function is to return an aggregate type such as a struct, the caller
1170 must allocate space into which the callee will copy the return value. In
1171 this case, a pointer to the return value location is passed into the callee
1172 in register R0, which displaces one of the other arguments passed in via
1173 registers R0 to R2. */
1176 avr_push_dummy_call (struct gdbarch
*gdbarch
, CORE_ADDR func_addr
,
1177 struct regcache
*regcache
, CORE_ADDR bp_addr
,
1178 int nargs
, struct value
**args
, CORE_ADDR sp
,
1179 int struct_return
, CORE_ADDR struct_addr
)
1182 unsigned char buf
[2];
1183 CORE_ADDR return_pc
= avr_convert_iaddr_to_raw (bp_addr
);
1184 int regnum
= AVR_ARGN_REGNUM
;
1185 struct stack_item
*si
= NULL
;
1188 /* FIXME: TRoth/2003-06-18: Not sure what to do when returning a struct. */
1191 fprintf_unfiltered (gdb_stderr
, "struct_return: 0x%lx\n", struct_addr
);
1192 write_register (argreg
--, struct_addr
& 0xff);
1193 write_register (argreg
--, (struct_addr
>>8) & 0xff);
1197 for (i
= 0; i
< nargs
; i
++)
1201 struct value
*arg
= args
[i
];
1202 struct type
*type
= check_typedef (VALUE_TYPE (arg
));
1203 char *contents
= VALUE_CONTENTS (arg
);
1204 int len
= TYPE_LENGTH (type
);
1206 /* Calculate the potential last register needed. */
1207 last_regnum
= regnum
- (len
+ (len
& 1));
1209 /* If there are registers available, use them. Once we start putting
1210 stuff on the stack, all subsequent args go on stack. */
1211 if ((si
== NULL
) && (last_regnum
>= 8))
1215 /* Skip a register for odd length args. */
1219 val
= extract_unsigned_integer (contents
, len
);
1220 for (j
=0; j
<len
; j
++)
1222 regcache_cooked_write_unsigned (regcache
, regnum
--,
1223 val
>> (8*(len
-j
-1)));
1226 /* No registers available, push the args onto the stack. */
1229 /* From here on, we don't care about regnum. */
1230 si
= push_stack_item (si
, contents
, len
);
1234 /* Push args onto the stack. */
1238 /* Add 1 to sp here to account for post decr nature of pushes. */
1239 write_memory (sp
+1, si
->data
, si
->len
);
1240 si
= pop_stack_item (si
);
1243 /* Set the return address. For the avr, the return address is the BP_ADDR.
1244 Need to push the return address onto the stack noting that it needs to be
1245 in big-endian order on the stack. */
1246 buf
[0] = (return_pc
>> 8) & 0xff;
1247 buf
[1] = return_pc
& 0xff;
1250 write_memory (sp
+1, buf
, 2); /* Add one since pushes are post decr ops. */
1252 /* Finally, update the SP register. */
1253 regcache_cooked_write_unsigned (regcache
, AVR_SP_REGNUM
,
1254 avr_convert_saddr_to_raw (sp
));
1259 /* Initialize the gdbarch structure for the AVR's. */
1261 static struct gdbarch
*
1262 avr_gdbarch_init (struct gdbarch_info info
, struct gdbarch_list
*arches
)
1264 struct gdbarch
*gdbarch
;
1265 struct gdbarch_tdep
*tdep
;
1267 /* Find a candidate among the list of pre-declared architectures. */
1268 arches
= gdbarch_list_lookup_by_info (arches
, &info
);
1270 return arches
->gdbarch
;
1272 /* None found, create a new architecture from the information provided. */
1273 tdep
= XMALLOC (struct gdbarch_tdep
);
1274 gdbarch
= gdbarch_alloc (&info
, tdep
);
1276 /* If we ever need to differentiate the device types, do it here. */
1277 switch (info
.bfd_arch_info
->mach
)
1287 set_gdbarch_short_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1288 set_gdbarch_int_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1289 set_gdbarch_long_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1290 set_gdbarch_long_long_bit (gdbarch
, 8 * TARGET_CHAR_BIT
);
1291 set_gdbarch_ptr_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1292 set_gdbarch_addr_bit (gdbarch
, 32);
1294 set_gdbarch_float_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1295 set_gdbarch_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1296 set_gdbarch_long_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1298 set_gdbarch_float_format (gdbarch
, &floatformat_ieee_single_little
);
1299 set_gdbarch_double_format (gdbarch
, &floatformat_ieee_single_little
);
1300 set_gdbarch_long_double_format (gdbarch
, &floatformat_ieee_single_little
);
1302 set_gdbarch_read_pc (gdbarch
, avr_read_pc
);
1303 set_gdbarch_write_pc (gdbarch
, avr_write_pc
);
1304 set_gdbarch_read_sp (gdbarch
, avr_read_sp
);
1306 set_gdbarch_num_regs (gdbarch
, AVR_NUM_REGS
);
1308 set_gdbarch_sp_regnum (gdbarch
, AVR_SP_REGNUM
);
1309 set_gdbarch_pc_regnum (gdbarch
, AVR_PC_REGNUM
);
1311 set_gdbarch_register_name (gdbarch
, avr_register_name
);
1312 set_gdbarch_register_type (gdbarch
, avr_register_type
);
1314 set_gdbarch_extract_return_value (gdbarch
, avr_extract_return_value
);
1315 set_gdbarch_print_insn (gdbarch
, print_insn_avr
);
1317 set_gdbarch_push_dummy_call (gdbarch
, avr_push_dummy_call
);
1319 set_gdbarch_address_to_pointer (gdbarch
, avr_address_to_pointer
);
1320 set_gdbarch_pointer_to_address (gdbarch
, avr_pointer_to_address
);
1322 set_gdbarch_use_struct_convention (gdbarch
, generic_use_struct_convention
);
1324 set_gdbarch_skip_prologue (gdbarch
, avr_skip_prologue
);
1325 set_gdbarch_inner_than (gdbarch
, core_addr_lessthan
);
1327 set_gdbarch_decr_pc_after_break (gdbarch
, 0);
1328 set_gdbarch_breakpoint_from_pc (gdbarch
, avr_breakpoint_from_pc
);
1330 set_gdbarch_function_start_offset (gdbarch
, 0);
1332 set_gdbarch_frame_args_skip (gdbarch
, 0);
1333 set_gdbarch_frameless_function_invocation (gdbarch
,
1334 frameless_look_for_prologue
);
1336 frame_unwind_append_sniffer (gdbarch
, avr_frame_sniffer
);
1337 frame_base_set_default (gdbarch
, &avr_frame_base
);
1339 set_gdbarch_unwind_dummy_id (gdbarch
, avr_unwind_dummy_id
);
1341 set_gdbarch_unwind_pc (gdbarch
, avr_unwind_pc
);
1346 /* Send a query request to the avr remote target asking for values of the io
1347 registers. If args parameter is not NULL, then the user has requested info
1348 on a specific io register [This still needs implemented and is ignored for
1349 now]. The query string should be one of these forms:
1351 "Ravr.io_reg" -> reply is "NN" number of io registers
1353 "Ravr.io_reg:addr,len" where addr is first register and len is number of
1354 registers to be read. The reply should be "<NAME>,VV;" for each io register
1355 where, <NAME> is a string, and VV is the hex value of the register.
1357 All io registers are 8-bit. */
1360 avr_io_reg_read_command (char *args
, int from_tty
)
1366 unsigned int nreg
= 0;
1370 if (!current_target
.to_query
)
1372 fprintf_unfiltered (gdb_stderr
,
1373 "ERR: info io_registers NOT supported by current "
1378 /* Just get the maximum buffer size. */
1379 target_query ((int) 'R', 0, 0, &bufsiz
);
1380 if (bufsiz
> sizeof (buf
))
1381 bufsiz
= sizeof (buf
);
1383 /* Find out how many io registers the target has. */
1384 strcpy (query
, "avr.io_reg");
1385 target_query ((int) 'R', query
, buf
, &bufsiz
);
1387 if (strncmp (buf
, "", bufsiz
) == 0)
1389 fprintf_unfiltered (gdb_stderr
,
1390 "info io_registers NOT supported by target\n");
1394 if (sscanf (buf
, "%x", &nreg
) != 1)
1396 fprintf_unfiltered (gdb_stderr
,
1397 "Error fetching number of io registers\n");
1401 reinitialize_more_filter ();
1403 printf_unfiltered ("Target has %u io registers:\n\n", nreg
);
1405 /* only fetch up to 8 registers at a time to keep the buffer small */
1408 for (i
= 0; i
< nreg
; i
+= step
)
1410 /* how many registers this round? */
1413 j
= nreg
- i
; /* last block is less than 8 registers */
1415 snprintf (query
, sizeof (query
) - 1, "avr.io_reg:%x,%x", i
, j
);
1416 target_query ((int) 'R', query
, buf
, &bufsiz
);
1419 for (k
= i
; k
< (i
+ j
); k
++)
1421 if (sscanf (p
, "%[^,],%x;", query
, &val
) == 2)
1423 printf_filtered ("[%02x] %-15s : %02x\n", k
, query
, val
);
1424 while ((*p
!= ';') && (*p
!= '\0'))
1426 p
++; /* skip over ';' */
1434 extern initialize_file_ftype _initialize_avr_tdep
; /* -Wmissing-prototypes */
1437 _initialize_avr_tdep (void)
1439 register_gdbarch_init (bfd_arch_avr
, avr_gdbarch_init
);
1441 /* Add a new command to allow the user to query the avr remote target for
1442 the values of the io space registers in a saner way than just using
1445 /* FIXME: TRoth/2002-02-18: This should probably be changed to 'info avr
1446 io_registers' to signify it is not available on other platforms. */
1448 add_cmd ("io_registers", class_info
, avr_io_reg_read_command
,
1449 "query remote avr target for io space register values", &infolist
);