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 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street, Fifth Floor,
21 Boston, MA 02110-1301, USA. */
23 /* Contributed by Theodore A. Roth, troth@openavr.org */
25 /* Portions of this file were taken from the original gdb-4.18 patch developed
26 by Denis Chertykov, denisc@overta.ru */
30 #include "frame-unwind.h"
31 #include "frame-base.h"
32 #include "trad-frame.h"
38 #include "arch-utils.h"
40 #include "gdb_string.h"
45 (AVR micros are pure Harvard Architecture processors.)
47 The AVR family of microcontrollers have three distinctly different memory
48 spaces: flash, sram and eeprom. The flash is 16 bits wide and is used for
49 the most part to store program instructions. The sram is 8 bits wide and is
50 used for the stack and the heap. Some devices lack sram and some can have
51 an additional external sram added on as a peripheral.
53 The eeprom is 8 bits wide and is used to store data when the device is
54 powered down. Eeprom is not directly accessible, it can only be accessed
55 via io-registers using a special algorithm. Accessing eeprom via gdb's
56 remote serial protocol ('m' or 'M' packets) looks difficult to do and is
57 not included at this time.
59 [The eeprom could be read manually via ``x/b <eaddr + AVR_EMEM_START>'' or
60 written using ``set {unsigned char}<eaddr + AVR_EMEM_START>''. For this to
61 work, the remote target must be able to handle eeprom accesses and perform
62 the address translation.]
64 All three memory spaces have physical addresses beginning at 0x0. In
65 addition, the flash is addressed by gcc/binutils/gdb with respect to 8 bit
66 bytes instead of the 16 bit wide words used by the real device for the
69 In order for remote targets to work correctly, extra bits must be added to
70 addresses before they are send to the target or received from the target
71 via the remote serial protocol. The extra bits are the MSBs and are used to
72 decode which memory space the address is referring to. */
75 #define XMALLOC(TYPE) ((TYPE*) xmalloc (sizeof (TYPE)))
78 #define EXTRACT_INSN(addr) extract_unsigned_integer(addr,2)
80 /* Constants: prefixed with AVR_ to avoid name space clashes */
94 AVR_NUM_REGS
= 32 + 1 /*SREG*/ + 1 /*SP*/ + 1 /*PC*/,
95 AVR_NUM_REG_BYTES
= 32 + 1 /*SREG*/ + 2 /*SP*/ + 4 /*PC*/,
97 AVR_PC_REG_INDEX
= 35, /* index into array of registers */
99 AVR_MAX_PROLOGUE_SIZE
= 64, /* bytes */
101 /* Count of pushed registers. From r2 to r17 (inclusively), r28, r29 */
104 /* Number of the last pushed register. r17 for current avr-gcc */
105 AVR_LAST_PUSHED_REGNUM
= 17,
107 AVR_ARG1_REGNUM
= 24, /* Single byte argument */
108 AVR_ARGN_REGNUM
= 25, /* Multi byte argments */
110 AVR_RET1_REGNUM
= 24, /* Single byte return value */
111 AVR_RETN_REGNUM
= 25, /* Multi byte return value */
113 /* FIXME: TRoth/2002-01-??: Can we shift all these memory masks left 8
114 bits? Do these have to match the bfd vma values?. It sure would make
115 things easier in the future if they didn't need to match.
117 Note: I chose these values so as to be consistent with bfd vma
120 TRoth/2002-04-08: There is already a conflict with very large programs
121 in the mega128. The mega128 has 128K instruction bytes (64K words),
122 thus the Most Significant Bit is 0x10000 which gets masked off my
125 The problem manifests itself when trying to set a breakpoint in a
126 function which resides in the upper half of the instruction space and
127 thus requires a 17-bit address.
129 For now, I've just removed the EEPROM mask and changed AVR_MEM_MASK
130 from 0x00ff0000 to 0x00f00000. Eeprom is not accessible from gdb yet,
131 but could be for some remote targets by just adding the correct offset
132 to the address and letting the remote target handle the low-level
133 details of actually accessing the eeprom. */
135 AVR_IMEM_START
= 0x00000000, /* INSN memory */
136 AVR_SMEM_START
= 0x00800000, /* SRAM memory */
138 /* No eeprom mask defined */
139 AVR_MEM_MASK
= 0x00f00000, /* mask to determine memory space */
141 AVR_EMEM_START
= 0x00810000, /* EEPROM memory */
142 AVR_MEM_MASK
= 0x00ff0000, /* mask to determine memory space */
148 NORMAL and CALL are the typical types (the -mcall-prologues gcc option
149 causes the generation of the CALL type prologues). */
152 AVR_PROLOGUE_NONE
, /* No prologue */
154 AVR_PROLOGUE_CALL
, /* -mcall-prologues */
156 AVR_PROLOGUE_INTR
, /* interrupt handler */
157 AVR_PROLOGUE_SIG
, /* signal handler */
160 /* Any function with a frame looks like this
161 ....... <-SP POINTS HERE
162 LOCALS1 <-FP POINTS HERE
171 struct avr_unwind_cache
173 /* The previous frame's inner most stack address. Used as this
174 frame ID's stack_addr. */
176 /* The frame's base, optionally used by the high-level debug info. */
180 /* Table indicating the location of each and every register. */
181 struct trad_frame_saved_reg
*saved_regs
;
186 /* FIXME: TRoth: is there anything to put here? */
190 /* Lookup the name of a register given it's number. */
193 avr_register_name (int regnum
)
195 static char *register_names
[] = {
196 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
197 "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
198 "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
199 "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
204 if (regnum
>= (sizeof (register_names
) / sizeof (*register_names
)))
206 return register_names
[regnum
];
209 /* Return the GDB type object for the "standard" data type
210 of data in register N. */
213 avr_register_type (struct gdbarch
*gdbarch
, int reg_nr
)
215 if (reg_nr
== AVR_PC_REGNUM
)
216 return builtin_type_uint32
;
217 if (reg_nr
== AVR_SP_REGNUM
)
218 return builtin_type_void_data_ptr
;
220 return builtin_type_uint8
;
223 /* Instruction address checks and convertions. */
226 avr_make_iaddr (CORE_ADDR x
)
228 return ((x
) | AVR_IMEM_START
);
231 /* FIXME: TRoth: Really need to use a larger mask for instructions. Some
232 devices are already up to 128KBytes of flash space.
234 TRoth/2002-04-8: See comment above where AVR_IMEM_START is defined. */
237 avr_convert_iaddr_to_raw (CORE_ADDR x
)
239 return ((x
) & 0xffffffff);
242 /* SRAM address checks and convertions. */
245 avr_make_saddr (CORE_ADDR x
)
247 return ((x
) | AVR_SMEM_START
);
251 avr_convert_saddr_to_raw (CORE_ADDR x
)
253 return ((x
) & 0xffffffff);
256 /* EEPROM address checks and convertions. I don't know if these will ever
257 actually be used, but I've added them just the same. TRoth */
259 /* TRoth/2002-04-08: Commented out for now to allow fix for problem with large
260 programs in the mega128. */
262 /* static CORE_ADDR */
263 /* avr_make_eaddr (CORE_ADDR x) */
265 /* return ((x) | AVR_EMEM_START); */
269 /* avr_eaddr_p (CORE_ADDR x) */
271 /* return (((x) & AVR_MEM_MASK) == AVR_EMEM_START); */
274 /* static CORE_ADDR */
275 /* avr_convert_eaddr_to_raw (CORE_ADDR x) */
277 /* return ((x) & 0xffffffff); */
280 /* Convert from address to pointer and vice-versa. */
283 avr_address_to_pointer (struct type
*type
, gdb_byte
*buf
, CORE_ADDR addr
)
285 /* Is it a code address? */
286 if (TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_FUNC
287 || TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_METHOD
)
289 store_unsigned_integer (buf
, TYPE_LENGTH (type
),
290 avr_convert_iaddr_to_raw (addr
>> 1));
294 /* Strip off any upper segment bits. */
295 store_unsigned_integer (buf
, TYPE_LENGTH (type
),
296 avr_convert_saddr_to_raw (addr
));
301 avr_pointer_to_address (struct type
*type
, const gdb_byte
*buf
)
303 CORE_ADDR addr
= extract_unsigned_integer (buf
, TYPE_LENGTH (type
));
305 /* Is it a code address? */
306 if (TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_FUNC
307 || TYPE_CODE (TYPE_TARGET_TYPE (type
)) == TYPE_CODE_METHOD
308 || TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type
)))
309 return avr_make_iaddr (addr
<< 1);
311 return avr_make_saddr (addr
);
315 avr_read_pc (struct regcache
*regcache
)
318 regcache_cooked_read_unsigned (regcache
, AVR_PC_REGNUM
, &pc
);
319 return avr_make_iaddr (pc
);
323 avr_write_pc (struct regcache
*regcache
, CORE_ADDR val
)
325 regcache_cooked_write_unsigned (regcache
, AVR_PC_REGNUM
,
326 avr_convert_iaddr_to_raw (val
));
330 avr_scan_arg_moves (int vpc
, unsigned char *prologue
)
334 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
336 insn
= EXTRACT_INSN (&prologue
[vpc
]);
337 if ((insn
& 0xff00) == 0x0100) /* movw rXX, rYY */
339 else if ((insn
& 0xfc00) == 0x2c00) /* mov rXX, rYY */
348 /* Function: avr_scan_prologue
350 This function decodes an AVR function prologue to determine:
351 1) the size of the stack frame
352 2) which registers are saved on it
353 3) the offsets of saved regs
354 This information is stored in the avr_unwind_cache structure.
356 Some devices lack the sbiw instruction, so on those replace this:
362 A typical AVR function prologue with a frame pointer might look like this:
363 push rXX ; saved regs
369 sbiw r28,<LOCALS_SIZE>
370 in __tmp_reg__,__SREG__
373 out __SREG__,__tmp_reg__
376 A typical AVR function prologue without a frame pointer might look like
378 push rXX ; saved regs
381 A main function prologue looks like this:
382 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
383 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
387 A signal handler prologue looks like this:
390 in __tmp_reg__, __SREG__
393 push rXX ; save registers r18:r27, r30:r31
395 push r28 ; save frame pointer
399 sbiw r28, <LOCALS_SIZE>
403 A interrupt handler prologue looks like this:
407 in __tmp_reg__, __SREG__
410 push rXX ; save registers r18:r27, r30:r31
412 push r28 ; save frame pointer
416 sbiw r28, <LOCALS_SIZE>
422 A `-mcall-prologues' prologue looks like this (Note that the megas use a
423 jmp instead of a rjmp, thus the prologue is one word larger since jmp is a
424 32 bit insn and rjmp is a 16 bit insn):
425 ldi r26,lo8(<LOCALS_SIZE>)
426 ldi r27,hi8(<LOCALS_SIZE>)
427 ldi r30,pm_lo8(.L_foo_body)
428 ldi r31,pm_hi8(.L_foo_body)
429 rjmp __prologue_saves__+RRR
432 /* Not really part of a prologue, but still need to scan for it, is when a
433 function prologue moves values passed via registers as arguments to new
434 registers. In this case, all local variables live in registers, so there
435 may be some register saves. This is what it looks like:
439 There could be multiple movw's. If the target doesn't have a movw insn, it
440 will use two mov insns. This could be done after any of the above prologue
444 avr_scan_prologue (CORE_ADDR pc
, struct avr_unwind_cache
*info
)
449 struct minimal_symbol
*msymbol
;
450 unsigned char prologue
[AVR_MAX_PROLOGUE_SIZE
];
453 /* FIXME: TRoth/2003-06-11: This could be made more efficient by only
454 reading in the bytes of the prologue. The problem is that the figuring
455 out where the end of the prologue is is a bit difficult. The old code
456 tried to do that, but failed quite often. */
457 read_memory (pc
, prologue
, AVR_MAX_PROLOGUE_SIZE
);
459 /* Scanning main()'s prologue
460 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
461 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
468 unsigned char img
[] = {
469 0xde, 0xbf, /* out __SP_H__,r29 */
470 0xcd, 0xbf /* out __SP_L__,r28 */
473 insn
= EXTRACT_INSN (&prologue
[vpc
]);
474 /* ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>) */
475 if ((insn
& 0xf0f0) == 0xe0c0)
477 locals
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
478 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
479 /* ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>) */
480 if ((insn
& 0xf0f0) == 0xe0d0)
482 locals
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
483 if (memcmp (prologue
+ vpc
+ 4, img
, sizeof (img
)) == 0)
485 info
->prologue_type
= AVR_PROLOGUE_MAIN
;
493 /* Scanning `-mcall-prologues' prologue
494 Classic prologue is 10 bytes, mega prologue is a 12 bytes long */
496 while (1) /* Using a while to avoid many goto's */
503 insn
= EXTRACT_INSN (&prologue
[vpc
]);
504 /* ldi r26,<LOCALS_SIZE> */
505 if ((insn
& 0xf0f0) != 0xe0a0)
507 loc_size
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
510 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
511 /* ldi r27,<LOCALS_SIZE> / 256 */
512 if ((insn
& 0xf0f0) != 0xe0b0)
514 loc_size
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
517 insn
= EXTRACT_INSN (&prologue
[vpc
+ 4]);
518 /* ldi r30,pm_lo8(.L_foo_body) */
519 if ((insn
& 0xf0f0) != 0xe0e0)
521 body_addr
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
524 insn
= EXTRACT_INSN (&prologue
[vpc
+ 6]);
525 /* ldi r31,pm_hi8(.L_foo_body) */
526 if ((insn
& 0xf0f0) != 0xe0f0)
528 body_addr
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
531 msymbol
= lookup_minimal_symbol ("__prologue_saves__", NULL
, NULL
);
535 insn
= EXTRACT_INSN (&prologue
[vpc
+ 8]);
536 /* rjmp __prologue_saves__+RRR */
537 if ((insn
& 0xf000) == 0xc000)
539 /* Extract PC relative offset from RJMP */
540 i
= (insn
& 0xfff) | (insn
& 0x800 ? (-1 ^ 0xfff) : 0);
541 /* Convert offset to byte addressable mode */
543 /* Destination address */
546 if (body_addr
!= (pc
+ 10)/2)
551 else if ((insn
& 0xfe0e) == 0x940c)
553 /* Extract absolute PC address from JMP */
554 i
= (((insn
& 0x1) | ((insn
& 0x1f0) >> 3) << 16)
555 | (EXTRACT_INSN (&prologue
[vpc
+ 10]) & 0xffff));
556 /* Convert address to byte addressable mode */
559 if (body_addr
!= (pc
+ 12)/2)
567 /* Resolve offset (in words) from __prologue_saves__ symbol.
568 Which is a pushes count in `-mcall-prologues' mode */
569 num_pushes
= AVR_MAX_PUSHES
- (i
- SYMBOL_VALUE_ADDRESS (msymbol
)) / 2;
571 if (num_pushes
> AVR_MAX_PUSHES
)
573 fprintf_unfiltered (gdb_stderr
, _("Num pushes too large: %d\n"),
582 info
->saved_regs
[AVR_FP_REGNUM
+ 1].addr
= num_pushes
;
584 info
->saved_regs
[AVR_FP_REGNUM
].addr
= num_pushes
- 1;
587 for (from
= AVR_LAST_PUSHED_REGNUM
+ 1 - (num_pushes
- 2);
588 from
<= AVR_LAST_PUSHED_REGNUM
; ++from
)
589 info
->saved_regs
[from
].addr
= ++i
;
591 info
->size
= loc_size
+ num_pushes
;
592 info
->prologue_type
= AVR_PROLOGUE_CALL
;
594 return pc
+ pc_offset
;
597 /* Scan for the beginning of the prologue for an interrupt or signal
598 function. Note that we have to set the prologue type here since the
599 third stage of the prologue may not be present (e.g. no saved registered
600 or changing of the SP register). */
604 unsigned char img
[] = {
605 0x78, 0x94, /* sei */
606 0x1f, 0x92, /* push r1 */
607 0x0f, 0x92, /* push r0 */
608 0x0f, 0xb6, /* in r0,0x3f SREG */
609 0x0f, 0x92, /* push r0 */
610 0x11, 0x24 /* clr r1 */
612 if (memcmp (prologue
, img
, sizeof (img
)) == 0)
614 info
->prologue_type
= AVR_PROLOGUE_INTR
;
616 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
617 info
->saved_regs
[0].addr
= 2;
618 info
->saved_regs
[1].addr
= 1;
621 else if (memcmp (img
+ 2, prologue
, sizeof (img
) - 2) == 0)
623 info
->prologue_type
= AVR_PROLOGUE_SIG
;
624 vpc
+= sizeof (img
) - 2;
625 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
626 info
->saved_regs
[0].addr
= 2;
627 info
->saved_regs
[1].addr
= 1;
632 /* First stage of the prologue scanning.
633 Scan pushes (saved registers) */
635 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
637 insn
= EXTRACT_INSN (&prologue
[vpc
]);
638 if ((insn
& 0xfe0f) == 0x920f) /* push rXX */
640 /* Bits 4-9 contain a mask for registers R0-R32. */
641 int regno
= (insn
& 0x1f0) >> 4;
643 info
->saved_regs
[regno
].addr
= info
->size
;
650 if (vpc
>= AVR_MAX_PROLOGUE_SIZE
)
651 fprintf_unfiltered (gdb_stderr
,
652 _("Hit end of prologue while scanning pushes\n"));
654 /* Second stage of the prologue scanning.
659 if (scan_stage
== 1 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
661 unsigned char img
[] = {
662 0xcd, 0xb7, /* in r28,__SP_L__ */
663 0xde, 0xb7 /* in r29,__SP_H__ */
665 unsigned short insn1
;
667 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
674 /* Third stage of the prologue scanning. (Really two stages)
676 sbiw r28,XX or subi r28,lo8(XX)
678 in __tmp_reg__,__SREG__
681 out __SREG__,__tmp_reg__
684 if (scan_stage
== 2 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
687 unsigned char img
[] = {
688 0x0f, 0xb6, /* in r0,0x3f */
689 0xf8, 0x94, /* cli */
690 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
691 0x0f, 0xbe, /* out 0x3f,r0 ; SREG */
692 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
694 unsigned char img_sig
[] = {
695 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
696 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
698 unsigned char img_int
[] = {
699 0xf8, 0x94, /* cli */
700 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
701 0x78, 0x94, /* sei */
702 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
705 insn
= EXTRACT_INSN (&prologue
[vpc
]);
707 if ((insn
& 0xff30) == 0x9720) /* sbiw r28,XXX */
708 locals_size
= (insn
& 0xf) | ((insn
& 0xc0) >> 2);
709 else if ((insn
& 0xf0f0) == 0x50c0) /* subi r28,lo8(XX) */
711 locals_size
= (insn
& 0xf) | ((insn
& 0xf00) >> 4);
712 insn
= EXTRACT_INSN (&prologue
[vpc
]);
714 locals_size
+= ((insn
& 0xf) | ((insn
& 0xf00) >> 4) << 8);
719 /* Scan the last part of the prologue. May not be present for interrupt
720 or signal handler functions, which is why we set the prologue type
721 when we saw the beginning of the prologue previously. */
723 if (memcmp (prologue
+ vpc
, img_sig
, sizeof (img_sig
)) == 0)
725 vpc
+= sizeof (img_sig
);
727 else if (memcmp (prologue
+ vpc
, img_int
, sizeof (img_int
)) == 0)
729 vpc
+= sizeof (img_int
);
731 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
733 info
->prologue_type
= AVR_PROLOGUE_NORMAL
;
737 info
->size
+= locals_size
;
739 return pc
+ avr_scan_arg_moves (vpc
, prologue
);
742 /* If we got this far, we could not scan the prologue, so just return the pc
743 of the frame plus an adjustment for argument move insns. */
745 return pc
+ avr_scan_arg_moves (vpc
, prologue
);;
749 avr_skip_prologue (CORE_ADDR pc
)
751 CORE_ADDR func_addr
, func_end
;
752 CORE_ADDR prologue_end
= pc
;
754 /* See what the symbol table says */
756 if (find_pc_partial_function (pc
, NULL
, &func_addr
, &func_end
))
758 struct symtab_and_line sal
;
759 struct avr_unwind_cache info
= {0};
760 struct trad_frame_saved_reg saved_regs
[AVR_NUM_REGS
];
762 info
.saved_regs
= saved_regs
;
764 /* Need to run the prologue scanner to figure out if the function has a
765 prologue and possibly skip over moving arguments passed via registers
766 to other registers. */
768 prologue_end
= avr_scan_prologue (pc
, &info
);
770 if (info
.prologue_type
== AVR_PROLOGUE_NONE
)
774 sal
= find_pc_line (func_addr
, 0);
776 if (sal
.line
!= 0 && sal
.end
< func_end
)
781 /* Either we didn't find the start of this function (nothing we can do),
782 or there's no line info, or the line after the prologue is after
783 the end of the function (there probably isn't a prologue). */
788 /* Not all avr devices support the BREAK insn. Those that don't should treat
789 it as a NOP. Thus, it should be ok. Since the avr is currently a remote
790 only target, this shouldn't be a problem (I hope). TRoth/2003-05-14 */
792 static const unsigned char *
793 avr_breakpoint_from_pc (CORE_ADDR
* pcptr
, int *lenptr
)
795 static unsigned char avr_break_insn
[] = { 0x98, 0x95 };
796 *lenptr
= sizeof (avr_break_insn
);
797 return avr_break_insn
;
800 /* Given a return value in `regbuf' with a type `valtype',
801 extract and copy its value into `valbuf'.
803 Return values are always passed via registers r25:r24:... */
806 avr_extract_return_value (struct type
*type
, struct regcache
*regcache
,
812 if (TYPE_LENGTH (type
) == 1)
814 regcache_cooked_read_unsigned (regcache
, 24, &c
);
815 store_unsigned_integer (valbuf
, 1, c
);
820 /* The MSB of the return value is always in r25, calculate which
821 register holds the LSB. */
822 int lsb_reg
= 25 - TYPE_LENGTH (type
) + 1;
824 for (i
=0; i
< TYPE_LENGTH (type
); i
++)
826 regcache_cooked_read (regcache
, lsb_reg
+ i
,
827 (bfd_byte
*) valbuf
+ i
);
832 /* Put here the code to store, into fi->saved_regs, the addresses of
833 the saved registers of frame described by FRAME_INFO. This
834 includes special registers such as pc and fp saved in special ways
835 in the stack frame. sp is even more special: the address we return
836 for it IS the sp for the next frame. */
838 struct avr_unwind_cache
*
839 avr_frame_unwind_cache (struct frame_info
*next_frame
,
840 void **this_prologue_cache
)
845 struct avr_unwind_cache
*info
;
848 if ((*this_prologue_cache
))
849 return (*this_prologue_cache
);
851 info
= FRAME_OBSTACK_ZALLOC (struct avr_unwind_cache
);
852 (*this_prologue_cache
) = info
;
853 info
->saved_regs
= trad_frame_alloc_saved_regs (next_frame
);
856 info
->prologue_type
= AVR_PROLOGUE_NONE
;
858 pc
= frame_func_unwind (next_frame
, NORMAL_FRAME
);
860 if ((pc
> 0) && (pc
< frame_pc_unwind (next_frame
)))
861 avr_scan_prologue (pc
, info
);
863 if ((info
->prologue_type
!= AVR_PROLOGUE_NONE
)
864 && (info
->prologue_type
!= AVR_PROLOGUE_MAIN
))
866 ULONGEST high_base
; /* High byte of FP */
868 /* The SP was moved to the FP. This indicates that a new frame
869 was created. Get THIS frame's FP value by unwinding it from
871 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
, &this_base
);
872 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
+1, &high_base
);
873 this_base
+= (high_base
<< 8);
875 /* The FP points at the last saved register. Adjust the FP back
876 to before the first saved register giving the SP. */
877 prev_sp
= this_base
+ info
->size
;
881 /* Assume that the FP is this frame's SP but with that pushed
882 stack space added back. */
883 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &this_base
);
884 prev_sp
= this_base
+ info
->size
;
887 /* Add 1 here to adjust for the post-decrement nature of the push
889 info
->prev_sp
= avr_make_saddr (prev_sp
+1);
891 info
->base
= avr_make_saddr (this_base
);
893 /* Adjust all the saved registers so that they contain addresses and not
895 for (i
= 0; i
< gdbarch_num_regs (current_gdbarch
) - 1; i
++)
896 if (info
->saved_regs
[i
].addr
)
898 info
->saved_regs
[i
].addr
= (info
->prev_sp
- info
->saved_regs
[i
].addr
);
901 /* Except for the main and startup code, the return PC is always saved on
902 the stack and is at the base of the frame. */
904 if (info
->prologue_type
!= AVR_PROLOGUE_MAIN
)
906 info
->saved_regs
[AVR_PC_REGNUM
].addr
= info
->prev_sp
;
909 /* The previous frame's SP needed to be computed. Save the computed
911 trad_frame_set_value (info
->saved_regs
, AVR_SP_REGNUM
, info
->prev_sp
+1);
917 avr_unwind_pc (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
921 frame_unwind_unsigned_register (next_frame
, AVR_PC_REGNUM
, &pc
);
923 return avr_make_iaddr (pc
);
927 avr_unwind_sp (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
931 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &sp
);
933 return avr_make_saddr (sp
);
936 /* Given a GDB frame, determine the address of the calling function's
937 frame. This will be used to create a new GDB frame struct. */
940 avr_frame_this_id (struct frame_info
*next_frame
,
941 void **this_prologue_cache
,
942 struct frame_id
*this_id
)
944 struct avr_unwind_cache
*info
945 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
950 /* The FUNC is easy. */
951 func
= frame_func_unwind (next_frame
, NORMAL_FRAME
);
953 /* Hopefully the prologue analysis either correctly determined the
954 frame's base (which is the SP from the previous frame), or set
955 that base to "NULL". */
956 base
= info
->prev_sp
;
960 id
= frame_id_build (base
, func
);
965 avr_frame_prev_register (struct frame_info
*next_frame
,
966 void **this_prologue_cache
,
967 int regnum
, int *optimizedp
,
968 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
969 int *realnump
, gdb_byte
*bufferp
)
971 struct avr_unwind_cache
*info
972 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
974 if (regnum
== AVR_PC_REGNUM
)
976 if (trad_frame_addr_p (info
->saved_regs
, regnum
))
979 *lvalp
= lval_memory
;
980 *addrp
= info
->saved_regs
[regnum
].addr
;
984 /* Reading the return PC from the PC register is slightly
985 abnormal. register_size(AVR_PC_REGNUM) says it is 4 bytes,
986 but in reality, only two bytes (3 in upcoming mega256) are
989 Also, note that the value on the stack is an addr to a word
990 not a byte, so we will need to multiply it by two at some
993 And to confuse matters even more, the return address stored
994 on the stack is in big endian byte order, even though most
995 everything else about the avr is little endian. Ick! */
997 /* FIXME: number of bytes read here will need updated for the
998 mega256 when it is available. */
1002 unsigned char buf
[2];
1004 read_memory (info
->saved_regs
[regnum
].addr
, buf
, 2);
1006 /* Convert the PC read from memory as a big-endian to
1007 little-endian order. */
1012 pc
= (extract_unsigned_integer (buf
, 2) * 2);
1013 store_unsigned_integer (bufferp
,
1014 register_size (current_gdbarch
, regnum
),
1020 trad_frame_get_prev_register (next_frame
, info
->saved_regs
, regnum
,
1021 optimizedp
, lvalp
, addrp
, realnump
, bufferp
);
1024 static const struct frame_unwind avr_frame_unwind
= {
1027 avr_frame_prev_register
1030 const struct frame_unwind
*
1031 avr_frame_sniffer (struct frame_info
*next_frame
)
1033 return &avr_frame_unwind
;
1037 avr_frame_base_address (struct frame_info
*next_frame
, void **this_cache
)
1039 struct avr_unwind_cache
*info
1040 = avr_frame_unwind_cache (next_frame
, this_cache
);
1045 static const struct frame_base avr_frame_base
= {
1047 avr_frame_base_address
,
1048 avr_frame_base_address
,
1049 avr_frame_base_address
1052 /* Assuming NEXT_FRAME->prev is a dummy, return the frame ID of that
1053 dummy frame. The frame ID's base needs to match the TOS value
1054 saved by save_dummy_frame_tos(), and the PC match the dummy frame's
1057 static struct frame_id
1058 avr_unwind_dummy_id (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
1062 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &base
);
1063 return frame_id_build (avr_make_saddr (base
), frame_pc_unwind (next_frame
));
1066 /* When arguments must be pushed onto the stack, they go on in reverse
1067 order. The below implements a FILO (stack) to do this. */
1072 struct stack_item
*prev
;
1076 static struct stack_item
*
1077 push_stack_item (struct stack_item
*prev
, const bfd_byte
*contents
, int len
)
1079 struct stack_item
*si
;
1080 si
= xmalloc (sizeof (struct stack_item
));
1081 si
->data
= xmalloc (len
);
1084 memcpy (si
->data
, contents
, len
);
1088 static struct stack_item
*pop_stack_item (struct stack_item
*si
);
1089 static struct stack_item
*
1090 pop_stack_item (struct stack_item
*si
)
1092 struct stack_item
*dead
= si
;
1099 /* Setup the function arguments for calling a function in the inferior.
1101 On the AVR architecture, there are 18 registers (R25 to R8) which are
1102 dedicated for passing function arguments. Up to the first 18 arguments
1103 (depending on size) may go into these registers. The rest go on the stack.
1105 All arguments are aligned to start in even-numbered registers (odd-sized
1106 arguments, including char, have one free register above them). For example,
1107 an int in arg1 and a char in arg2 would be passed as such:
1112 Arguments that are larger than 2 bytes will be split between two or more
1113 registers as available, but will NOT be split between a register and the
1114 stack. Arguments that go onto the stack are pushed last arg first (this is
1115 similar to the d10v). */
1117 /* NOTE: TRoth/2003-06-17: The rest of this comment is old looks to be
1120 An exceptional case exists for struct arguments (and possibly other
1121 aggregates such as arrays) -- if the size is larger than WORDSIZE bytes but
1122 not a multiple of WORDSIZE bytes. In this case the argument is never split
1123 between the registers and the stack, but instead is copied in its entirety
1124 onto the stack, AND also copied into as many registers as there is room
1125 for. In other words, space in registers permitting, two copies of the same
1126 argument are passed in. As far as I can tell, only the one on the stack is
1127 used, although that may be a function of the level of compiler
1128 optimization. I suspect this is a compiler bug. Arguments of these odd
1129 sizes are left-justified within the word (as opposed to arguments smaller
1130 than WORDSIZE bytes, which are right-justified).
1132 If the function is to return an aggregate type such as a struct, the caller
1133 must allocate space into which the callee will copy the return value. In
1134 this case, a pointer to the return value location is passed into the callee
1135 in register R0, which displaces one of the other arguments passed in via
1136 registers R0 to R2. */
1139 avr_push_dummy_call (struct gdbarch
*gdbarch
, struct value
*function
,
1140 struct regcache
*regcache
, CORE_ADDR bp_addr
,
1141 int nargs
, struct value
**args
, CORE_ADDR sp
,
1142 int struct_return
, CORE_ADDR struct_addr
)
1145 unsigned char buf
[2];
1146 CORE_ADDR return_pc
= avr_convert_iaddr_to_raw (bp_addr
);
1147 int regnum
= AVR_ARGN_REGNUM
;
1148 struct stack_item
*si
= NULL
;
1151 /* FIXME: TRoth/2003-06-18: Not sure what to do when returning a struct. */
1154 fprintf_unfiltered (gdb_stderr
, "struct_return: 0x%lx\n", struct_addr
);
1155 regcache_cooked_write_unsigned (regcache
, argreg
--, struct_addr
& 0xff);
1156 regcache_cooked_write_unsigned (regcache
, argreg
--, (struct_addr
>>8) & 0xff);
1160 for (i
= 0; i
< nargs
; i
++)
1164 struct value
*arg
= args
[i
];
1165 struct type
*type
= check_typedef (value_type (arg
));
1166 const bfd_byte
*contents
= value_contents (arg
);
1167 int len
= TYPE_LENGTH (type
);
1169 /* Calculate the potential last register needed. */
1170 last_regnum
= regnum
- (len
+ (len
& 1));
1172 /* If there are registers available, use them. Once we start putting
1173 stuff on the stack, all subsequent args go on stack. */
1174 if ((si
== NULL
) && (last_regnum
>= 8))
1178 /* Skip a register for odd length args. */
1182 val
= extract_unsigned_integer (contents
, len
);
1183 for (j
=0; j
<len
; j
++)
1185 regcache_cooked_write_unsigned (regcache
, regnum
--,
1186 val
>> (8*(len
-j
-1)));
1189 /* No registers available, push the args onto the stack. */
1192 /* From here on, we don't care about regnum. */
1193 si
= push_stack_item (si
, contents
, len
);
1197 /* Push args onto the stack. */
1201 /* Add 1 to sp here to account for post decr nature of pushes. */
1202 write_memory (sp
+1, si
->data
, si
->len
);
1203 si
= pop_stack_item (si
);
1206 /* Set the return address. For the avr, the return address is the BP_ADDR.
1207 Need to push the return address onto the stack noting that it needs to be
1208 in big-endian order on the stack. */
1209 buf
[0] = (return_pc
>> 8) & 0xff;
1210 buf
[1] = return_pc
& 0xff;
1213 write_memory (sp
+1, buf
, 2); /* Add one since pushes are post decr ops. */
1215 /* Finally, update the SP register. */
1216 regcache_cooked_write_unsigned (regcache
, AVR_SP_REGNUM
,
1217 avr_convert_saddr_to_raw (sp
));
1222 /* Initialize the gdbarch structure for the AVR's. */
1224 static struct gdbarch
*
1225 avr_gdbarch_init (struct gdbarch_info info
, struct gdbarch_list
*arches
)
1227 struct gdbarch
*gdbarch
;
1228 struct gdbarch_tdep
*tdep
;
1230 /* Find a candidate among the list of pre-declared architectures. */
1231 arches
= gdbarch_list_lookup_by_info (arches
, &info
);
1233 return arches
->gdbarch
;
1235 /* None found, create a new architecture from the information provided. */
1236 tdep
= XMALLOC (struct gdbarch_tdep
);
1237 gdbarch
= gdbarch_alloc (&info
, tdep
);
1239 /* If we ever need to differentiate the device types, do it here. */
1240 switch (info
.bfd_arch_info
->mach
)
1250 set_gdbarch_short_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1251 set_gdbarch_int_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1252 set_gdbarch_long_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1253 set_gdbarch_long_long_bit (gdbarch
, 8 * TARGET_CHAR_BIT
);
1254 set_gdbarch_ptr_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1255 set_gdbarch_addr_bit (gdbarch
, 32);
1257 set_gdbarch_float_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1258 set_gdbarch_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1259 set_gdbarch_long_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1261 set_gdbarch_float_format (gdbarch
, floatformats_ieee_single
);
1262 set_gdbarch_double_format (gdbarch
, floatformats_ieee_single
);
1263 set_gdbarch_long_double_format (gdbarch
, floatformats_ieee_single
);
1265 set_gdbarch_read_pc (gdbarch
, avr_read_pc
);
1266 set_gdbarch_write_pc (gdbarch
, avr_write_pc
);
1268 set_gdbarch_num_regs (gdbarch
, AVR_NUM_REGS
);
1270 set_gdbarch_sp_regnum (gdbarch
, AVR_SP_REGNUM
);
1271 set_gdbarch_pc_regnum (gdbarch
, AVR_PC_REGNUM
);
1273 set_gdbarch_register_name (gdbarch
, avr_register_name
);
1274 set_gdbarch_register_type (gdbarch
, avr_register_type
);
1276 set_gdbarch_extract_return_value (gdbarch
, avr_extract_return_value
);
1277 set_gdbarch_print_insn (gdbarch
, print_insn_avr
);
1279 set_gdbarch_push_dummy_call (gdbarch
, avr_push_dummy_call
);
1281 set_gdbarch_address_to_pointer (gdbarch
, avr_address_to_pointer
);
1282 set_gdbarch_pointer_to_address (gdbarch
, avr_pointer_to_address
);
1284 set_gdbarch_skip_prologue (gdbarch
, avr_skip_prologue
);
1285 set_gdbarch_inner_than (gdbarch
, core_addr_lessthan
);
1287 set_gdbarch_breakpoint_from_pc (gdbarch
, avr_breakpoint_from_pc
);
1289 frame_unwind_append_sniffer (gdbarch
, avr_frame_sniffer
);
1290 frame_base_set_default (gdbarch
, &avr_frame_base
);
1292 set_gdbarch_unwind_dummy_id (gdbarch
, avr_unwind_dummy_id
);
1294 set_gdbarch_unwind_pc (gdbarch
, avr_unwind_pc
);
1295 set_gdbarch_unwind_sp (gdbarch
, avr_unwind_sp
);
1300 /* Send a query request to the avr remote target asking for values of the io
1301 registers. If args parameter is not NULL, then the user has requested info
1302 on a specific io register [This still needs implemented and is ignored for
1303 now]. The query string should be one of these forms:
1305 "Ravr.io_reg" -> reply is "NN" number of io registers
1307 "Ravr.io_reg:addr,len" where addr is first register and len is number of
1308 registers to be read. The reply should be "<NAME>,VV;" for each io register
1309 where, <NAME> is a string, and VV is the hex value of the register.
1311 All io registers are 8-bit. */
1314 avr_io_reg_read_command (char *args
, int from_tty
)
1320 unsigned int nreg
= 0;
1324 /* Find out how many io registers the target has. */
1325 bufsiz
= target_read_alloc (¤t_target
, TARGET_OBJECT_AVR
,
1326 "avr.io_reg", &buf
);
1330 fprintf_unfiltered (gdb_stderr
,
1331 _("ERR: info io_registers NOT supported "
1332 "by current target\n"));
1336 if (sscanf (buf
, "%x", &nreg
) != 1)
1338 fprintf_unfiltered (gdb_stderr
,
1339 _("Error fetching number of io registers\n"));
1346 reinitialize_more_filter ();
1348 printf_unfiltered (_("Target has %u io registers:\n\n"), nreg
);
1350 /* only fetch up to 8 registers at a time to keep the buffer small */
1353 for (i
= 0; i
< nreg
; i
+= step
)
1355 /* how many registers this round? */
1358 j
= nreg
- i
; /* last block is less than 8 registers */
1360 snprintf (query
, sizeof (query
) - 1, "avr.io_reg:%x,%x", i
, j
);
1361 bufsiz
= target_read_alloc (¤t_target
, TARGET_OBJECT_AVR
,
1365 for (k
= i
; k
< (i
+ j
); k
++)
1367 if (sscanf (p
, "%[^,],%x;", query
, &val
) == 2)
1369 printf_filtered ("[%02x] %-15s : %02x\n", k
, query
, val
);
1370 while ((*p
!= ';') && (*p
!= '\0'))
1372 p
++; /* skip over ';' */
1382 extern initialize_file_ftype _initialize_avr_tdep
; /* -Wmissing-prototypes */
1385 _initialize_avr_tdep (void)
1387 register_gdbarch_init (bfd_arch_avr
, avr_gdbarch_init
);
1389 /* Add a new command to allow the user to query the avr remote target for
1390 the values of the io space registers in a saner way than just using
1393 /* FIXME: TRoth/2002-02-18: This should probably be changed to 'info avr
1394 io_registers' to signify it is not available on other platforms. */
1396 add_cmd ("io_registers", class_info
, avr_io_reg_read_command
,
1397 _("query remote avr target for io space register values"),