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"
42 (AVR micros are pure Harvard Architecture processors.)
44 The AVR family of microcontrollers have three distinctly different memory
45 spaces: flash, sram and eeprom. The flash is 16 bits wide and is used for
46 the most part to store program instructions. The sram is 8 bits wide and is
47 used for the stack and the heap. Some devices lack sram and some can have
48 an additional external sram added on as a peripheral.
50 The eeprom is 8 bits wide and is used to store data when the device is
51 powered down. Eeprom is not directly accessible, it can only be accessed
52 via io-registers using a special algorithm. Accessing eeprom via gdb's
53 remote serial protocol ('m' or 'M' packets) looks difficult to do and is
54 not included at this time.
56 [The eeprom could be read manually via ``x/b <eaddr + AVR_EMEM_START>'' or
57 written using ``set {unsigned char}<eaddr + AVR_EMEM_START>''. For this to
58 work, the remote target must be able to handle eeprom accesses and perform
59 the address translation.]
61 All three memory spaces have physical addresses beginning at 0x0. In
62 addition, the flash is addressed by gcc/binutils/gdb with respect to 8 bit
63 bytes instead of the 16 bit wide words used by the real device for the
66 In order for remote targets to work correctly, extra bits must be added to
67 addresses before they are send to the target or received from the target
68 via the remote serial protocol. The extra bits are the MSBs and are used to
69 decode which memory space the address is referring to. */
72 #define XMALLOC(TYPE) ((TYPE*) xmalloc (sizeof (TYPE)))
75 #define EXTRACT_INSN(addr) extract_unsigned_integer(addr,2)
77 /* Constants: prefixed with AVR_ to avoid name space clashes */
91 AVR_NUM_REGS
= 32 + 1 /*SREG*/ + 1 /*SP*/ + 1 /*PC*/,
92 AVR_NUM_REG_BYTES
= 32 + 1 /*SREG*/ + 2 /*SP*/ + 4 /*PC*/,
94 AVR_PC_REG_INDEX
= 35, /* index into array of registers */
96 AVR_MAX_PROLOGUE_SIZE
= 64, /* bytes */
98 /* Count of pushed registers. From r2 to r17 (inclusively), r28, r29 */
101 /* Number of the last pushed register. r17 for current avr-gcc */
102 AVR_LAST_PUSHED_REGNUM
= 17,
104 AVR_ARG1_REGNUM
= 24, /* Single byte argument */
105 AVR_ARGN_REGNUM
= 25, /* Multi byte argments */
107 AVR_RET1_REGNUM
= 24, /* Single byte return value */
108 AVR_RETN_REGNUM
= 25, /* Multi byte return value */
110 /* FIXME: TRoth/2002-01-??: Can we shift all these memory masks left 8
111 bits? Do these have to match the bfd vma values?. It sure would make
112 things easier in the future if they didn't need to match.
114 Note: I chose these values so as to be consistent with bfd vma
117 TRoth/2002-04-08: There is already a conflict with very large programs
118 in the mega128. The mega128 has 128K instruction bytes (64K words),
119 thus the Most Significant Bit is 0x10000 which gets masked off my
122 The problem manifests itself when trying to set a breakpoint in a
123 function which resides in the upper half of the instruction space and
124 thus requires a 17-bit address.
126 For now, I've just removed the EEPROM mask and changed AVR_MEM_MASK
127 from 0x00ff0000 to 0x00f00000. Eeprom is not accessible from gdb yet,
128 but could be for some remote targets by just adding the correct offset
129 to the address and letting the remote target handle the low-level
130 details of actually accessing the eeprom. */
132 AVR_IMEM_START
= 0x00000000, /* INSN memory */
133 AVR_SMEM_START
= 0x00800000, /* SRAM memory */
135 /* No eeprom mask defined */
136 AVR_MEM_MASK
= 0x00f00000, /* mask to determine memory space */
138 AVR_EMEM_START
= 0x00810000, /* EEPROM memory */
139 AVR_MEM_MASK
= 0x00ff0000, /* mask to determine memory space */
145 NORMAL and CALL are the typical types (the -mcall-prologues gcc option
146 causes the generation of the CALL type prologues). */
149 AVR_PROLOGUE_NONE
, /* No prologue */
151 AVR_PROLOGUE_CALL
, /* -mcall-prologues */
153 AVR_PROLOGUE_INTR
, /* interrupt handler */
154 AVR_PROLOGUE_SIG
, /* signal handler */
157 /* Any function with a frame looks like this
158 ....... <-SP POINTS HERE
159 LOCALS1 <-FP POINTS HERE
168 struct avr_unwind_cache
170 /* The previous frame's inner most stack address. Used as this
171 frame ID's stack_addr. */
173 /* The frame's base, optionally used by the high-level debug info. */
177 /* Table indicating the location of each and every register. */
178 struct trad_frame_saved_reg
*saved_regs
;
183 /* FIXME: TRoth: is there anything to put here? */
187 /* Lookup the name of a register given it's number. */
190 avr_register_name (int regnum
)
192 static char *register_names
[] = {
193 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
194 "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
195 "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
196 "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
201 if (regnum
>= (sizeof (register_names
) / sizeof (*register_names
)))
203 return register_names
[regnum
];
206 /* Return the GDB type object for the "standard" data type
207 of data in register N. */
210 avr_register_type (struct gdbarch
*gdbarch
, int reg_nr
)
212 if (reg_nr
== AVR_PC_REGNUM
)
213 return builtin_type_uint32
;
214 if (reg_nr
== AVR_SP_REGNUM
)
215 return builtin_type_void_data_ptr
;
217 return builtin_type_uint8
;
220 /* Instruction address checks and convertions. */
223 avr_make_iaddr (CORE_ADDR x
)
225 return ((x
) | AVR_IMEM_START
);
229 avr_iaddr_p (CORE_ADDR x
)
231 return (((x
) & AVR_MEM_MASK
) == AVR_IMEM_START
);
234 /* FIXME: TRoth: Really need to use a larger mask for instructions. Some
235 devices are already up to 128KBytes of flash space.
237 TRoth/2002-04-8: See comment above where AVR_IMEM_START is defined. */
240 avr_convert_iaddr_to_raw (CORE_ADDR x
)
242 return ((x
) & 0xffffffff);
245 /* SRAM address checks and convertions. */
248 avr_make_saddr (CORE_ADDR x
)
250 return ((x
) | AVR_SMEM_START
);
254 avr_saddr_p (CORE_ADDR x
)
256 return (((x
) & AVR_MEM_MASK
) == AVR_SMEM_START
);
260 avr_convert_saddr_to_raw (CORE_ADDR x
)
262 return ((x
) & 0xffffffff);
265 /* EEPROM address checks and convertions. I don't know if these will ever
266 actually be used, but I've added them just the same. TRoth */
268 /* TRoth/2002-04-08: Commented out for now to allow fix for problem with large
269 programs in the mega128. */
271 /* static CORE_ADDR */
272 /* avr_make_eaddr (CORE_ADDR x) */
274 /* return ((x) | AVR_EMEM_START); */
278 /* avr_eaddr_p (CORE_ADDR x) */
280 /* return (((x) & AVR_MEM_MASK) == AVR_EMEM_START); */
283 /* static CORE_ADDR */
284 /* avr_convert_eaddr_to_raw (CORE_ADDR x) */
286 /* return ((x) & 0xffffffff); */
289 /* Convert from address to pointer and vice-versa. */
292 avr_address_to_pointer (struct type
*type
, void *buf
, CORE_ADDR addr
)
294 /* Is it a code address? */
295 if (TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_FUNC
296 || TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_METHOD
)
298 store_unsigned_integer (buf
, TYPE_LENGTH (type
),
299 avr_convert_iaddr_to_raw (addr
>> 1));
303 /* Strip off any upper segment bits. */
304 store_unsigned_integer (buf
, TYPE_LENGTH (type
),
305 avr_convert_saddr_to_raw (addr
));
310 avr_pointer_to_address (struct type
*type
, const void *buf
)
312 CORE_ADDR addr
= extract_unsigned_integer (buf
, TYPE_LENGTH (type
));
314 /* Is it a code address? */
315 if (TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_FUNC
316 || TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_METHOD
317 || TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type
)))
318 return avr_make_iaddr (addr
<< 1);
320 return avr_make_saddr (addr
);
324 avr_read_pc (ptid_t ptid
)
330 save_ptid
= inferior_ptid
;
331 inferior_ptid
= ptid
;
332 pc
= (int) read_register (AVR_PC_REGNUM
);
333 inferior_ptid
= save_ptid
;
334 retval
= avr_make_iaddr (pc
);
339 avr_write_pc (CORE_ADDR val
, ptid_t ptid
)
343 save_ptid
= inferior_ptid
;
344 inferior_ptid
= ptid
;
345 write_register (AVR_PC_REGNUM
, avr_convert_iaddr_to_raw (val
));
346 inferior_ptid
= save_ptid
;
352 return (avr_make_saddr (read_register (AVR_SP_REGNUM
)));
356 avr_scan_arg_moves (int vpc
, unsigned char *prologue
)
360 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
362 insn
= EXTRACT_INSN (&prologue
[vpc
]);
363 if ((insn
& 0xff00) == 0x0100) /* movw rXX, rYY */
365 else if ((insn
& 0xfc00) == 0x2c00) /* mov rXX, rYY */
374 /* Function: avr_scan_prologue
376 This function decodes an AVR function prologue to determine:
377 1) the size of the stack frame
378 2) which registers are saved on it
379 3) the offsets of saved regs
380 This information is stored in the avr_unwind_cache structure.
382 Some devices lack the sbiw instruction, so on those replace this:
388 A typical AVR function prologue with a frame pointer might look like this:
389 push rXX ; saved regs
395 sbiw r28,<LOCALS_SIZE>
396 in __tmp_reg__,__SREG__
399 out __SREG__,__tmp_reg__
402 A typical AVR function prologue without a frame pointer might look like
404 push rXX ; saved regs
407 A main function prologue looks like this:
408 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
409 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
413 A signal handler prologue looks like this:
416 in __tmp_reg__, __SREG__
419 push rXX ; save registers r18:r27, r30:r31
421 push r28 ; save frame pointer
425 sbiw r28, <LOCALS_SIZE>
429 A interrupt handler prologue looks like this:
433 in __tmp_reg__, __SREG__
436 push rXX ; save registers r18:r27, r30:r31
438 push r28 ; save frame pointer
442 sbiw r28, <LOCALS_SIZE>
448 A `-mcall-prologues' prologue looks like this (Note that the megas use a
449 jmp instead of a rjmp, thus the prologue is one word larger since jmp is a
450 32 bit insn and rjmp is a 16 bit insn):
451 ldi r26,lo8(<LOCALS_SIZE>)
452 ldi r27,hi8(<LOCALS_SIZE>)
453 ldi r30,pm_lo8(.L_foo_body)
454 ldi r31,pm_hi8(.L_foo_body)
455 rjmp __prologue_saves__+RRR
458 /* Not really part of a prologue, but still need to scan for it, is when a
459 function prologue moves values passed via registers as arguments to new
460 registers. In this case, all local variables live in registers, so there
461 may be some register saves. This is what it looks like:
465 There could be multiple movw's. If the target doesn't have a movw insn, it
466 will use two mov insns. This could be done after any of the above prologue
470 avr_scan_prologue (CORE_ADDR pc
, struct avr_unwind_cache
*info
)
475 struct minimal_symbol
*msymbol
;
476 unsigned char prologue
[AVR_MAX_PROLOGUE_SIZE
];
479 /* FIXME: TRoth/2003-06-11: This could be made more efficient by only
480 reading in the bytes of the prologue. The problem is that the figuring
481 out where the end of the prologue is is a bit difficult. The old code
482 tried to do that, but failed quite often. */
483 read_memory (pc
, prologue
, AVR_MAX_PROLOGUE_SIZE
);
485 /* Scanning main()'s prologue
486 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
487 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
494 unsigned char img
[] = {
495 0xde, 0xbf, /* out __SP_H__,r29 */
496 0xcd, 0xbf /* out __SP_L__,r28 */
499 insn
= EXTRACT_INSN (&prologue
[vpc
]);
500 /* ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>) */
501 if ((insn
& 0xf0f0) == 0xe0c0)
503 locals
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
504 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
505 /* ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>) */
506 if ((insn
& 0xf0f0) == 0xe0d0)
508 locals
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
509 if (memcmp (prologue
+ vpc
+ 4, img
, sizeof (img
)) == 0)
511 info
->prologue_type
= AVR_PROLOGUE_MAIN
;
519 /* Scanning `-mcall-prologues' prologue
520 Classic prologue is 10 bytes, mega prologue is a 12 bytes long */
522 while (1) /* Using a while to avoid many goto's */
529 insn
= EXTRACT_INSN (&prologue
[vpc
]);
530 /* ldi r26,<LOCALS_SIZE> */
531 if ((insn
& 0xf0f0) != 0xe0a0)
533 loc_size
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
536 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
537 /* ldi r27,<LOCALS_SIZE> / 256 */
538 if ((insn
& 0xf0f0) != 0xe0b0)
540 loc_size
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
543 insn
= EXTRACT_INSN (&prologue
[vpc
+ 4]);
544 /* ldi r30,pm_lo8(.L_foo_body) */
545 if ((insn
& 0xf0f0) != 0xe0e0)
547 body_addr
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
550 insn
= EXTRACT_INSN (&prologue
[vpc
+ 6]);
551 /* ldi r31,pm_hi8(.L_foo_body) */
552 if ((insn
& 0xf0f0) != 0xe0f0)
554 body_addr
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
557 msymbol
= lookup_minimal_symbol ("__prologue_saves__", NULL
, NULL
);
561 insn
= EXTRACT_INSN (&prologue
[vpc
+ 8]);
562 /* rjmp __prologue_saves__+RRR */
563 if ((insn
& 0xf000) == 0xc000)
565 /* Extract PC relative offset from RJMP */
566 i
= (insn
& 0xfff) | (insn
& 0x800 ? (-1 ^ 0xfff) : 0);
567 /* Convert offset to byte addressable mode */
569 /* Destination address */
572 if (body_addr
!= (pc
+ 10)/2)
577 else if ((insn
& 0xfe0e) == 0x940c)
579 /* Extract absolute PC address from JMP */
580 i
= (((insn
& 0x1) | ((insn
& 0x1f0) >> 3) << 16)
581 | (EXTRACT_INSN (&prologue
[vpc
+ 10]) & 0xffff));
582 /* Convert address to byte addressable mode */
585 if (body_addr
!= (pc
+ 12)/2)
593 /* Resolve offset (in words) from __prologue_saves__ symbol.
594 Which is a pushes count in `-mcall-prologues' mode */
595 num_pushes
= AVR_MAX_PUSHES
- (i
- SYMBOL_VALUE_ADDRESS (msymbol
)) / 2;
597 if (num_pushes
> AVR_MAX_PUSHES
)
599 fprintf_unfiltered (gdb_stderr
, "Num pushes too large: %d\n",
608 info
->saved_regs
[AVR_FP_REGNUM
+ 1].addr
= num_pushes
;
610 info
->saved_regs
[AVR_FP_REGNUM
].addr
= num_pushes
- 1;
613 for (from
= AVR_LAST_PUSHED_REGNUM
+ 1 - (num_pushes
- 2);
614 from
<= AVR_LAST_PUSHED_REGNUM
; ++from
)
615 info
->saved_regs
[from
].addr
= ++i
;
617 info
->size
= loc_size
+ num_pushes
;
618 info
->prologue_type
= AVR_PROLOGUE_CALL
;
620 return pc
+ pc_offset
;
623 /* Scan for the beginning of the prologue for an interrupt or signal
624 function. Note that we have to set the prologue type here since the
625 third stage of the prologue may not be present (e.g. no saved registered
626 or changing of the SP register). */
630 unsigned char img
[] = {
631 0x78, 0x94, /* sei */
632 0x1f, 0x92, /* push r1 */
633 0x0f, 0x92, /* push r0 */
634 0x0f, 0xb6, /* in r0,0x3f SREG */
635 0x0f, 0x92, /* push r0 */
636 0x11, 0x24 /* clr r1 */
638 if (memcmp (prologue
, img
, sizeof (img
)) == 0)
640 info
->prologue_type
= AVR_PROLOGUE_INTR
;
642 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
643 info
->saved_regs
[0].addr
= 2;
644 info
->saved_regs
[1].addr
= 1;
647 else if (memcmp (img
+ 2, prologue
, sizeof (img
) - 2) == 0)
649 info
->prologue_type
= AVR_PROLOGUE_SIG
;
650 vpc
+= sizeof (img
) - 2;
651 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
652 info
->saved_regs
[0].addr
= 2;
653 info
->saved_regs
[1].addr
= 1;
658 /* First stage of the prologue scanning.
659 Scan pushes (saved registers) */
661 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
663 insn
= EXTRACT_INSN (&prologue
[vpc
]);
664 if ((insn
& 0xfe0f) == 0x920f) /* push rXX */
666 /* Bits 4-9 contain a mask for registers R0-R32. */
667 int regno
= (insn
& 0x1f0) >> 4;
669 info
->saved_regs
[regno
].addr
= info
->size
;
676 if (vpc
>= AVR_MAX_PROLOGUE_SIZE
)
677 fprintf_unfiltered (gdb_stderr
,
678 "Hit end of prologue while scanning pushes\n");
680 /* Second stage of the prologue scanning.
685 if (scan_stage
== 1 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
687 unsigned char img
[] = {
688 0xcd, 0xb7, /* in r28,__SP_L__ */
689 0xde, 0xb7 /* in r29,__SP_H__ */
691 unsigned short insn1
;
693 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
700 /* Third stage of the prologue scanning. (Really two stages)
702 sbiw r28,XX or subi r28,lo8(XX)
704 in __tmp_reg__,__SREG__
707 out __SREG__,__tmp_reg__
710 if (scan_stage
== 2 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
713 unsigned char img
[] = {
714 0x0f, 0xb6, /* in r0,0x3f */
715 0xf8, 0x94, /* cli */
716 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
717 0x0f, 0xbe, /* out 0x3f,r0 ; SREG */
718 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
720 unsigned char img_sig
[] = {
721 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
722 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
724 unsigned char img_int
[] = {
725 0xf8, 0x94, /* cli */
726 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
727 0x78, 0x94, /* sei */
728 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
731 insn
= EXTRACT_INSN (&prologue
[vpc
]);
733 if ((insn
& 0xff30) == 0x9720) /* sbiw r28,XXX */
734 locals_size
= (insn
& 0xf) | ((insn
& 0xc0) >> 2);
735 else if ((insn
& 0xf0f0) == 0x50c0) /* subi r28,lo8(XX) */
737 locals_size
= (insn
& 0xf) | ((insn
& 0xf00) >> 4);
738 insn
= EXTRACT_INSN (&prologue
[vpc
]);
740 locals_size
+= ((insn
& 0xf) | ((insn
& 0xf00) >> 4) << 8);
745 /* Scan the last part of the prologue. May not be present for interrupt
746 or signal handler functions, which is why we set the prologue type
747 when we saw the beginning of the prologue previously. */
749 if (memcmp (prologue
+ vpc
, img_sig
, sizeof (img_sig
)) == 0)
751 vpc
+= sizeof (img_sig
);
753 else if (memcmp (prologue
+ vpc
, img_int
, sizeof (img_int
)) == 0)
755 vpc
+= sizeof (img_int
);
757 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
759 info
->prologue_type
= AVR_PROLOGUE_NORMAL
;
763 info
->size
+= locals_size
;
765 return pc
+ avr_scan_arg_moves (vpc
, prologue
);
768 /* If we got this far, we could not scan the prologue, so just return the pc
769 of the frame plus an adjustment for argument move insns. */
771 return pc
+ avr_scan_arg_moves (vpc
, prologue
);;
774 /* Returns the return address for a dummy. */
777 avr_call_dummy_address (void)
779 return entry_point_address ();
783 avr_skip_prologue (CORE_ADDR pc
)
785 CORE_ADDR func_addr
, func_end
;
786 CORE_ADDR prologue_end
= pc
;
788 /* See what the symbol table says */
790 if (find_pc_partial_function (pc
, NULL
, &func_addr
, &func_end
))
792 struct symtab_and_line sal
;
793 struct avr_unwind_cache info
= {0};
794 struct trad_frame_saved_reg saved_regs
[AVR_NUM_REGS
];
796 info
.saved_regs
= saved_regs
;
798 /* Need to run the prologue scanner to figure out if the function has a
799 prologue and possibly skip over moving arguments passed via registers
800 to other registers. */
802 prologue_end
= avr_scan_prologue (pc
, &info
);
804 if (info
.prologue_type
!= AVR_PROLOGUE_NONE
)
806 sal
= find_pc_line (func_addr
, 0);
808 if (sal
.line
!= 0 && sal
.end
< func_end
)
813 /* Either we didn't find the start of this function (nothing we can do),
814 or there's no line info, or the line after the prologue is after
815 the end of the function (there probably isn't a prologue). */
820 /* Not all avr devices support the BREAK insn. Those that don't should treat
821 it as a NOP. Thus, it should be ok. Since the avr is currently a remote
822 only target, this shouldn't be a problem (I hope). TRoth/2003-05-14 */
824 static const unsigned char *
825 avr_breakpoint_from_pc (CORE_ADDR
* pcptr
, int *lenptr
)
827 static unsigned char avr_break_insn
[] = { 0x98, 0x95 };
828 *lenptr
= sizeof (avr_break_insn
);
829 return avr_break_insn
;
832 /* Given a return value in `regbuf' with a type `valtype',
833 extract and copy its value into `valbuf'.
835 Return values are always passed via registers r25:r24:... */
838 avr_extract_return_value (struct type
*type
, struct regcache
*regcache
,
844 if (TYPE_LENGTH (type
) == 1)
846 regcache_cooked_read_unsigned (regcache
, 24, &c
);
847 store_unsigned_integer (valbuf
, 1, c
);
852 /* The MSB of the return value is always in r25, calculate which
853 register holds the LSB. */
854 int lsb_reg
= 25 - TYPE_LENGTH (type
) + 1;
856 for (i
=0; i
< TYPE_LENGTH (type
); i
++)
858 regcache_cooked_read (regcache
, lsb_reg
+ i
,
859 (bfd_byte
*) valbuf
+ i
);
865 avr_saved_regs_unwinder (struct frame_info
*next_frame
,
866 struct trad_frame_saved_reg
*this_saved_regs
,
867 int regnum
, int *optimizedp
,
868 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
869 int *realnump
, void *bufferp
)
871 if (this_saved_regs
[regnum
].addr
!= 0)
874 *lvalp
= lval_memory
;
875 *addrp
= this_saved_regs
[regnum
].addr
;
879 /* Read the value in from memory. */
881 if (regnum
== AVR_PC_REGNUM
)
883 /* Reading the return PC from the PC register is slightly
884 abnormal. register_size(AVR_PC_REGNUM) says it is 4 bytes,
885 but in reality, only two bytes (3 in upcoming mega256) are
888 Also, note that the value on the stack is an addr to a word
889 not a byte, so we will need to multiply it by two at some
892 And to confuse matters even more, the return address stored
893 on the stack is in big endian byte order, even though most
894 everything else about the avr is little endian. Ick! */
896 /* FIXME: number of bytes read here will need updated for the
897 mega256 when it is available. */
901 unsigned char buf
[2];
903 read_memory (this_saved_regs
[regnum
].addr
, buf
, 2);
905 /* Convert the PC read from memory as a big-endian to
906 little-endian order. */
911 pc
= (extract_unsigned_integer (buf
, 2) * 2);
912 store_unsigned_integer (bufferp
,
913 register_size (current_gdbarch
, regnum
),
918 read_memory (this_saved_regs
[regnum
].addr
, bufferp
,
919 register_size (current_gdbarch
, regnum
));
926 /* No luck, assume this and the next frame have the same register
927 value. If a value is needed, pass the request on down the chain;
928 otherwise just return an indication that the value is in the same
929 register as the next frame. */
930 frame_register_unwind (next_frame
, regnum
, optimizedp
, lvalp
, addrp
,
934 /* Put here the code to store, into fi->saved_regs, the addresses of
935 the saved registers of frame described by FRAME_INFO. This
936 includes special registers such as pc and fp saved in special ways
937 in the stack frame. sp is even more special: the address we return
938 for it IS the sp for the next frame. */
940 struct avr_unwind_cache
*
941 avr_frame_unwind_cache (struct frame_info
*next_frame
,
942 void **this_prologue_cache
)
947 struct avr_unwind_cache
*info
;
950 if ((*this_prologue_cache
))
951 return (*this_prologue_cache
);
953 info
= FRAME_OBSTACK_ZALLOC (struct avr_unwind_cache
);
954 (*this_prologue_cache
) = info
;
955 info
->saved_regs
= trad_frame_alloc_saved_regs (next_frame
);
958 info
->prologue_type
= AVR_PROLOGUE_NONE
;
960 pc
= frame_func_unwind (next_frame
);
962 if ((pc
> 0) && (pc
< frame_pc_unwind (next_frame
)))
963 avr_scan_prologue (pc
, info
);
965 if (info
->prologue_type
!= AVR_PROLOGUE_NONE
)
967 ULONGEST high_base
; /* High byte of FP */
969 /* The SP was moved to the FP. This indicates that a new frame
970 was created. Get THIS frame's FP value by unwinding it from
972 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
, &this_base
);
973 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
+1, &high_base
);
974 this_base
+= (high_base
<< 8);
976 /* The FP points at the last saved register. Adjust the FP back
977 to before the first saved register giving the SP. */
978 prev_sp
= this_base
+ info
->size
;
982 /* Assume that the FP is this frame's SP but with that pushed
983 stack space added back. */
984 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &this_base
);
985 prev_sp
= this_base
+ info
->size
;
988 /* Add 1 here to adjust for the post-decrement nature of the push
990 info
->prev_sp
= avr_make_saddr (prev_sp
+1);
992 info
->base
= avr_make_saddr (this_base
);
994 /* Adjust all the saved registers so that they contain addresses and not
995 offsets. We need to add one to the addresses since push ops are post
996 decrement on the avr. */
997 for (i
= 0; i
< NUM_REGS
- 1; i
++)
998 if (info
->saved_regs
[i
].addr
)
1000 info
->saved_regs
[i
].addr
= (info
->prev_sp
- info
->saved_regs
[i
].addr
);
1003 /* Except for the main and startup code, the return PC is always saved on
1004 the stack and is at the base of the frame. */
1006 if (info
->prologue_type
!= AVR_PROLOGUE_MAIN
)
1008 info
->saved_regs
[AVR_PC_REGNUM
].addr
= info
->prev_sp
;
1015 avr_unwind_pc (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
1019 frame_unwind_unsigned_register (next_frame
, AVR_PC_REGNUM
, &pc
);
1021 return avr_make_iaddr (pc
);
1024 /* Given a GDB frame, determine the address of the calling function's
1025 frame. This will be used to create a new GDB frame struct. */
1028 avr_frame_this_id (struct frame_info
*next_frame
,
1029 void **this_prologue_cache
,
1030 struct frame_id
*this_id
)
1032 struct avr_unwind_cache
*info
1033 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
1038 /* The FUNC is easy. */
1039 func
= frame_func_unwind (next_frame
);
1041 /* This is meant to halt the backtrace at "_start". Make sure we
1042 don't halt it at a generic dummy frame. */
1043 if (inside_entry_file (func
))
1046 /* Hopefully the prologue analysis either correctly determined the
1047 frame's base (which is the SP from the previous frame), or set
1048 that base to "NULL". */
1049 base
= info
->prev_sp
;
1053 id
= frame_id_build (base
, func
);
1055 /* Check that we're not going round in circles with the same frame
1056 ID (but avoid applying the test to sentinel frames which do go
1057 round in circles). Can't use frame_id_eq() as that doesn't yet
1058 compare the frame's PC value. */
1059 if (frame_relative_level (next_frame
) >= 0
1060 && get_frame_type (next_frame
) != DUMMY_FRAME
1061 && frame_id_eq (get_frame_id (next_frame
), id
))
1068 avr_frame_prev_register (struct frame_info
*next_frame
,
1069 void **this_prologue_cache
,
1070 int regnum
, int *optimizedp
,
1071 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
1072 int *realnump
, void *bufferp
)
1074 struct avr_unwind_cache
*info
1075 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
1077 avr_saved_regs_unwinder (next_frame
, info
->saved_regs
, regnum
, optimizedp
,
1078 lvalp
, addrp
, realnump
, bufferp
);
1081 static const struct frame_unwind avr_frame_unwind
= {
1084 avr_frame_prev_register
1087 const struct frame_unwind
*
1088 avr_frame_p (CORE_ADDR pc
)
1090 return &avr_frame_unwind
;
1094 avr_frame_base_address (struct frame_info
*next_frame
, void **this_cache
)
1096 struct avr_unwind_cache
*info
1097 = avr_frame_unwind_cache (next_frame
, this_cache
);
1102 static const struct frame_base avr_frame_base
= {
1104 avr_frame_base_address
,
1105 avr_frame_base_address
,
1106 avr_frame_base_address
1109 /* Assuming NEXT_FRAME->prev is a dummy, return the frame ID of that
1110 dummy frame. The frame ID's base needs to match the TOS value
1111 saved by save_dummy_frame_tos(), and the PC match the dummy frame's
1114 static struct frame_id
1115 avr_unwind_dummy_id (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
1119 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &base
);
1120 return frame_id_build (avr_make_saddr (base
), frame_pc_unwind (next_frame
));
1123 /* When arguments must be pushed onto the stack, they go on in reverse
1124 order. The below implements a FILO (stack) to do this. */
1129 struct stack_item
*prev
;
1133 static struct stack_item
*push_stack_item (struct stack_item
*prev
,
1134 void *contents
, int len
);
1135 static struct stack_item
*
1136 push_stack_item (struct stack_item
*prev
, void *contents
, int len
)
1138 struct stack_item
*si
;
1139 si
= xmalloc (sizeof (struct stack_item
));
1140 si
->data
= xmalloc (len
);
1143 memcpy (si
->data
, contents
, len
);
1147 static struct stack_item
*pop_stack_item (struct stack_item
*si
);
1148 static struct stack_item
*
1149 pop_stack_item (struct stack_item
*si
)
1151 struct stack_item
*dead
= si
;
1158 /* Setup the function arguments for calling a function in the inferior.
1160 On the AVR architecture, there are 18 registers (R25 to R8) which are
1161 dedicated for passing function arguments. Up to the first 18 arguments
1162 (depending on size) may go into these registers. The rest go on the stack.
1164 All arguments are aligned to start in even-numbered registers (odd-sized
1165 arguments, including char, have one free register above them). For example,
1166 an int in arg1 and a char in arg2 would be passed as such:
1171 Arguments that are larger than 2 bytes will be split between two or more
1172 registers as available, but will NOT be split between a register and the
1173 stack. Arguments that go onto the stack are pushed last arg first (this is
1174 similar to the d10v). */
1176 /* NOTE: TRoth/2003-06-17: The rest of this comment is old looks to be
1179 An exceptional case exists for struct arguments (and possibly other
1180 aggregates such as arrays) -- if the size is larger than WORDSIZE bytes but
1181 not a multiple of WORDSIZE bytes. In this case the argument is never split
1182 between the registers and the stack, but instead is copied in its entirety
1183 onto the stack, AND also copied into as many registers as there is room
1184 for. In other words, space in registers permitting, two copies of the same
1185 argument are passed in. As far as I can tell, only the one on the stack is
1186 used, although that may be a function of the level of compiler
1187 optimization. I suspect this is a compiler bug. Arguments of these odd
1188 sizes are left-justified within the word (as opposed to arguments smaller
1189 than WORDSIZE bytes, which are right-justified).
1191 If the function is to return an aggregate type such as a struct, the caller
1192 must allocate space into which the callee will copy the return value. In
1193 this case, a pointer to the return value location is passed into the callee
1194 in register R0, which displaces one of the other arguments passed in via
1195 registers R0 to R2. */
1198 avr_push_dummy_call (struct gdbarch
*gdbarch
, CORE_ADDR func_addr
,
1199 struct regcache
*regcache
, CORE_ADDR bp_addr
,
1200 int nargs
, struct value
**args
, CORE_ADDR sp
,
1201 int struct_return
, CORE_ADDR struct_addr
)
1204 unsigned char buf
[2];
1205 CORE_ADDR return_pc
= avr_convert_iaddr_to_raw (bp_addr
);
1206 int regnum
= AVR_ARGN_REGNUM
;
1207 struct stack_item
*si
= NULL
;
1210 /* FIXME: TRoth/2003-06-18: Not sure what to do when returning a struct. */
1213 fprintf_unfiltered (gdb_stderr
, "struct_return: 0x%lx\n", struct_addr
);
1214 write_register (argreg
--, struct_addr
& 0xff);
1215 write_register (argreg
--, (struct_addr
>>8) & 0xff);
1219 for (i
= 0; i
< nargs
; i
++)
1223 struct value
*arg
= args
[i
];
1224 struct type
*type
= check_typedef (VALUE_TYPE (arg
));
1225 char *contents
= VALUE_CONTENTS (arg
);
1226 int len
= TYPE_LENGTH (type
);
1228 /* Calculate the potential last register needed. */
1229 last_regnum
= regnum
- (len
+ (len
& 1));
1231 /* If there are registers available, use them. Once we start putting
1232 stuff on the stack, all subsequent args go on stack. */
1233 if ((si
== NULL
) && (last_regnum
>= 8))
1237 /* Skip a register for odd length args. */
1241 val
= extract_unsigned_integer (contents
, len
);
1242 for (j
=0; j
<len
; j
++)
1244 regcache_cooked_write_unsigned (regcache
, regnum
--,
1245 val
>> (8*(len
-j
-1)));
1248 /* No registers available, push the args onto the stack. */
1251 /* From here on, we don't care about regnum. */
1252 si
= push_stack_item (si
, contents
, len
);
1256 /* Push args onto the stack. */
1260 /* Add 1 to sp here to account for post decr nature of pushes. */
1261 write_memory (sp
+1, si
->data
, si
->len
);
1262 si
= pop_stack_item (si
);
1265 /* Set the return address. For the avr, the return address is the BP_ADDR.
1266 Need to push the return address onto the stack noting that it needs to be
1267 in big-endian order on the stack. */
1268 buf
[0] = (return_pc
>> 8) & 0xff;
1269 buf
[1] = return_pc
& 0xff;
1272 write_memory (sp
+1, buf
, 2); /* Add one since pushes are post decr ops. */
1274 /* Finally, update the SP register. */
1275 regcache_cooked_write_unsigned (regcache
, AVR_SP_REGNUM
,
1276 avr_convert_saddr_to_raw (sp
));
1281 /* Initialize the gdbarch structure for the AVR's. */
1283 static struct gdbarch
*
1284 avr_gdbarch_init (struct gdbarch_info info
, struct gdbarch_list
*arches
)
1286 struct gdbarch
*gdbarch
;
1287 struct gdbarch_tdep
*tdep
;
1289 /* Find a candidate among the list of pre-declared architectures. */
1290 arches
= gdbarch_list_lookup_by_info (arches
, &info
);
1292 return arches
->gdbarch
;
1294 /* None found, create a new architecture from the information provided. */
1295 tdep
= XMALLOC (struct gdbarch_tdep
);
1296 gdbarch
= gdbarch_alloc (&info
, tdep
);
1298 /* If we ever need to differentiate the device types, do it here. */
1299 switch (info
.bfd_arch_info
->mach
)
1309 set_gdbarch_short_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1310 set_gdbarch_int_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1311 set_gdbarch_long_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1312 set_gdbarch_long_long_bit (gdbarch
, 8 * TARGET_CHAR_BIT
);
1313 set_gdbarch_ptr_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1314 set_gdbarch_addr_bit (gdbarch
, 32);
1315 set_gdbarch_bfd_vma_bit (gdbarch
, 32); /* FIXME: TRoth/2002-02-18: Is this needed? */
1317 set_gdbarch_float_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1318 set_gdbarch_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1319 set_gdbarch_long_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1321 set_gdbarch_float_format (gdbarch
, &floatformat_ieee_single_little
);
1322 set_gdbarch_double_format (gdbarch
, &floatformat_ieee_single_little
);
1323 set_gdbarch_long_double_format (gdbarch
, &floatformat_ieee_single_little
);
1325 set_gdbarch_read_pc (gdbarch
, avr_read_pc
);
1326 set_gdbarch_write_pc (gdbarch
, avr_write_pc
);
1327 set_gdbarch_read_sp (gdbarch
, avr_read_sp
);
1329 set_gdbarch_num_regs (gdbarch
, AVR_NUM_REGS
);
1331 set_gdbarch_sp_regnum (gdbarch
, AVR_SP_REGNUM
);
1332 set_gdbarch_pc_regnum (gdbarch
, AVR_PC_REGNUM
);
1334 set_gdbarch_register_name (gdbarch
, avr_register_name
);
1335 set_gdbarch_register_type (gdbarch
, avr_register_type
);
1337 set_gdbarch_extract_return_value (gdbarch
, avr_extract_return_value
);
1338 set_gdbarch_print_insn (gdbarch
, print_insn_avr
);
1340 set_gdbarch_call_dummy_address (gdbarch
, avr_call_dummy_address
);
1341 set_gdbarch_push_dummy_call (gdbarch
, avr_push_dummy_call
);
1343 set_gdbarch_address_to_pointer (gdbarch
, avr_address_to_pointer
);
1344 set_gdbarch_pointer_to_address (gdbarch
, avr_pointer_to_address
);
1346 set_gdbarch_use_struct_convention (gdbarch
, generic_use_struct_convention
);
1348 set_gdbarch_skip_prologue (gdbarch
, avr_skip_prologue
);
1349 set_gdbarch_inner_than (gdbarch
, core_addr_lessthan
);
1351 set_gdbarch_decr_pc_after_break (gdbarch
, 0);
1352 set_gdbarch_breakpoint_from_pc (gdbarch
, avr_breakpoint_from_pc
);
1354 set_gdbarch_function_start_offset (gdbarch
, 0);
1356 set_gdbarch_frame_args_skip (gdbarch
, 0);
1357 set_gdbarch_frameless_function_invocation (gdbarch
,
1358 frameless_look_for_prologue
);
1360 frame_unwind_append_predicate (gdbarch
, avr_frame_p
);
1361 frame_base_set_default (gdbarch
, &avr_frame_base
);
1363 set_gdbarch_unwind_dummy_id (gdbarch
, avr_unwind_dummy_id
);
1365 set_gdbarch_unwind_pc (gdbarch
, avr_unwind_pc
);
1370 /* Send a query request to the avr remote target asking for values of the io
1371 registers. If args parameter is not NULL, then the user has requested info
1372 on a specific io register [This still needs implemented and is ignored for
1373 now]. The query string should be one of these forms:
1375 "Ravr.io_reg" -> reply is "NN" number of io registers
1377 "Ravr.io_reg:addr,len" where addr is first register and len is number of
1378 registers to be read. The reply should be "<NAME>,VV;" for each io register
1379 where, <NAME> is a string, and VV is the hex value of the register.
1381 All io registers are 8-bit. */
1384 avr_io_reg_read_command (char *args
, int from_tty
)
1390 unsigned int nreg
= 0;
1394 if (!current_target
.to_query
)
1396 fprintf_unfiltered (gdb_stderr
,
1397 "ERR: info io_registers NOT supported by current "
1402 /* Just get the maximum buffer size. */
1403 target_query ((int) 'R', 0, 0, &bufsiz
);
1404 if (bufsiz
> sizeof (buf
))
1405 bufsiz
= sizeof (buf
);
1407 /* Find out how many io registers the target has. */
1408 strcpy (query
, "avr.io_reg");
1409 target_query ((int) 'R', query
, buf
, &bufsiz
);
1411 if (strncmp (buf
, "", bufsiz
) == 0)
1413 fprintf_unfiltered (gdb_stderr
,
1414 "info io_registers NOT supported by target\n");
1418 if (sscanf (buf
, "%x", &nreg
) != 1)
1420 fprintf_unfiltered (gdb_stderr
,
1421 "Error fetching number of io registers\n");
1425 reinitialize_more_filter ();
1427 printf_unfiltered ("Target has %u io registers:\n\n", nreg
);
1429 /* only fetch up to 8 registers at a time to keep the buffer small */
1432 for (i
= 0; i
< nreg
; i
+= step
)
1434 /* how many registers this round? */
1437 j
= nreg
- i
; /* last block is less than 8 registers */
1439 snprintf (query
, sizeof (query
) - 1, "avr.io_reg:%x,%x", i
, j
);
1440 target_query ((int) 'R', query
, buf
, &bufsiz
);
1443 for (k
= i
; k
< (i
+ j
); k
++)
1445 if (sscanf (p
, "%[^,],%x;", query
, &val
) == 2)
1447 printf_filtered ("[%02x] %-15s : %02x\n", k
, query
, val
);
1448 while ((*p
!= ';') && (*p
!= '\0'))
1450 p
++; /* skip over ';' */
1458 extern initialize_file_ftype _initialize_avr_tdep
; /* -Wmissing-prototypes */
1461 _initialize_avr_tdep (void)
1463 register_gdbarch_init (bfd_arch_avr
, avr_gdbarch_init
);
1465 /* Add a new command to allow the user to query the avr remote target for
1466 the values of the io space registers in a saner way than just using
1469 /* FIXME: TRoth/2002-02-18: This should probably be changed to 'info avr
1470 io_registers' to signify it is not available on other platforms. */
1472 add_cmd ("io_registers", class_info
, avr_io_reg_read_command
,
1473 "query remote avr target for io space register values", &infolist
);