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 (ptid_t ptid
)
321 save_ptid
= inferior_ptid
;
322 inferior_ptid
= ptid
;
323 regcache_cooked_read_unsigned (current_regcache
, AVR_PC_REGNUM
, &pc
);
324 inferior_ptid
= save_ptid
;
325 retval
= avr_make_iaddr (pc
);
330 avr_write_pc (CORE_ADDR val
, ptid_t ptid
)
334 save_ptid
= inferior_ptid
;
335 inferior_ptid
= ptid
;
336 write_register (AVR_PC_REGNUM
, avr_convert_iaddr_to_raw (val
));
337 inferior_ptid
= save_ptid
;
341 avr_scan_arg_moves (int vpc
, unsigned char *prologue
)
345 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
347 insn
= EXTRACT_INSN (&prologue
[vpc
]);
348 if ((insn
& 0xff00) == 0x0100) /* movw rXX, rYY */
350 else if ((insn
& 0xfc00) == 0x2c00) /* mov rXX, rYY */
359 /* Function: avr_scan_prologue
361 This function decodes an AVR function prologue to determine:
362 1) the size of the stack frame
363 2) which registers are saved on it
364 3) the offsets of saved regs
365 This information is stored in the avr_unwind_cache structure.
367 Some devices lack the sbiw instruction, so on those replace this:
373 A typical AVR function prologue with a frame pointer might look like this:
374 push rXX ; saved regs
380 sbiw r28,<LOCALS_SIZE>
381 in __tmp_reg__,__SREG__
384 out __SREG__,__tmp_reg__
387 A typical AVR function prologue without a frame pointer might look like
389 push rXX ; saved regs
392 A main function prologue looks like this:
393 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
394 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
398 A signal handler prologue looks like this:
401 in __tmp_reg__, __SREG__
404 push rXX ; save registers r18:r27, r30:r31
406 push r28 ; save frame pointer
410 sbiw r28, <LOCALS_SIZE>
414 A interrupt handler prologue looks like this:
418 in __tmp_reg__, __SREG__
421 push rXX ; save registers r18:r27, r30:r31
423 push r28 ; save frame pointer
427 sbiw r28, <LOCALS_SIZE>
433 A `-mcall-prologues' prologue looks like this (Note that the megas use a
434 jmp instead of a rjmp, thus the prologue is one word larger since jmp is a
435 32 bit insn and rjmp is a 16 bit insn):
436 ldi r26,lo8(<LOCALS_SIZE>)
437 ldi r27,hi8(<LOCALS_SIZE>)
438 ldi r30,pm_lo8(.L_foo_body)
439 ldi r31,pm_hi8(.L_foo_body)
440 rjmp __prologue_saves__+RRR
443 /* Not really part of a prologue, but still need to scan for it, is when a
444 function prologue moves values passed via registers as arguments to new
445 registers. In this case, all local variables live in registers, so there
446 may be some register saves. This is what it looks like:
450 There could be multiple movw's. If the target doesn't have a movw insn, it
451 will use two mov insns. This could be done after any of the above prologue
455 avr_scan_prologue (CORE_ADDR pc
, struct avr_unwind_cache
*info
)
460 struct minimal_symbol
*msymbol
;
461 unsigned char prologue
[AVR_MAX_PROLOGUE_SIZE
];
464 /* FIXME: TRoth/2003-06-11: This could be made more efficient by only
465 reading in the bytes of the prologue. The problem is that the figuring
466 out where the end of the prologue is is a bit difficult. The old code
467 tried to do that, but failed quite often. */
468 read_memory (pc
, prologue
, AVR_MAX_PROLOGUE_SIZE
);
470 /* Scanning main()'s prologue
471 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
472 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
479 unsigned char img
[] = {
480 0xde, 0xbf, /* out __SP_H__,r29 */
481 0xcd, 0xbf /* out __SP_L__,r28 */
484 insn
= EXTRACT_INSN (&prologue
[vpc
]);
485 /* ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>) */
486 if ((insn
& 0xf0f0) == 0xe0c0)
488 locals
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
489 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
490 /* ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>) */
491 if ((insn
& 0xf0f0) == 0xe0d0)
493 locals
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
494 if (memcmp (prologue
+ vpc
+ 4, img
, sizeof (img
)) == 0)
496 info
->prologue_type
= AVR_PROLOGUE_MAIN
;
504 /* Scanning `-mcall-prologues' prologue
505 Classic prologue is 10 bytes, mega prologue is a 12 bytes long */
507 while (1) /* Using a while to avoid many goto's */
514 insn
= EXTRACT_INSN (&prologue
[vpc
]);
515 /* ldi r26,<LOCALS_SIZE> */
516 if ((insn
& 0xf0f0) != 0xe0a0)
518 loc_size
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
521 insn
= EXTRACT_INSN (&prologue
[vpc
+ 2]);
522 /* ldi r27,<LOCALS_SIZE> / 256 */
523 if ((insn
& 0xf0f0) != 0xe0b0)
525 loc_size
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
528 insn
= EXTRACT_INSN (&prologue
[vpc
+ 4]);
529 /* ldi r30,pm_lo8(.L_foo_body) */
530 if ((insn
& 0xf0f0) != 0xe0e0)
532 body_addr
= (insn
& 0xf) | ((insn
& 0x0f00) >> 4);
535 insn
= EXTRACT_INSN (&prologue
[vpc
+ 6]);
536 /* ldi r31,pm_hi8(.L_foo_body) */
537 if ((insn
& 0xf0f0) != 0xe0f0)
539 body_addr
|= ((insn
& 0xf) | ((insn
& 0x0f00) >> 4)) << 8;
542 msymbol
= lookup_minimal_symbol ("__prologue_saves__", NULL
, NULL
);
546 insn
= EXTRACT_INSN (&prologue
[vpc
+ 8]);
547 /* rjmp __prologue_saves__+RRR */
548 if ((insn
& 0xf000) == 0xc000)
550 /* Extract PC relative offset from RJMP */
551 i
= (insn
& 0xfff) | (insn
& 0x800 ? (-1 ^ 0xfff) : 0);
552 /* Convert offset to byte addressable mode */
554 /* Destination address */
557 if (body_addr
!= (pc
+ 10)/2)
562 else if ((insn
& 0xfe0e) == 0x940c)
564 /* Extract absolute PC address from JMP */
565 i
= (((insn
& 0x1) | ((insn
& 0x1f0) >> 3) << 16)
566 | (EXTRACT_INSN (&prologue
[vpc
+ 10]) & 0xffff));
567 /* Convert address to byte addressable mode */
570 if (body_addr
!= (pc
+ 12)/2)
578 /* Resolve offset (in words) from __prologue_saves__ symbol.
579 Which is a pushes count in `-mcall-prologues' mode */
580 num_pushes
= AVR_MAX_PUSHES
- (i
- SYMBOL_VALUE_ADDRESS (msymbol
)) / 2;
582 if (num_pushes
> AVR_MAX_PUSHES
)
584 fprintf_unfiltered (gdb_stderr
, _("Num pushes too large: %d\n"),
593 info
->saved_regs
[AVR_FP_REGNUM
+ 1].addr
= num_pushes
;
595 info
->saved_regs
[AVR_FP_REGNUM
].addr
= num_pushes
- 1;
598 for (from
= AVR_LAST_PUSHED_REGNUM
+ 1 - (num_pushes
- 2);
599 from
<= AVR_LAST_PUSHED_REGNUM
; ++from
)
600 info
->saved_regs
[from
].addr
= ++i
;
602 info
->size
= loc_size
+ num_pushes
;
603 info
->prologue_type
= AVR_PROLOGUE_CALL
;
605 return pc
+ pc_offset
;
608 /* Scan for the beginning of the prologue for an interrupt or signal
609 function. Note that we have to set the prologue type here since the
610 third stage of the prologue may not be present (e.g. no saved registered
611 or changing of the SP register). */
615 unsigned char img
[] = {
616 0x78, 0x94, /* sei */
617 0x1f, 0x92, /* push r1 */
618 0x0f, 0x92, /* push r0 */
619 0x0f, 0xb6, /* in r0,0x3f SREG */
620 0x0f, 0x92, /* push r0 */
621 0x11, 0x24 /* clr r1 */
623 if (memcmp (prologue
, img
, sizeof (img
)) == 0)
625 info
->prologue_type
= AVR_PROLOGUE_INTR
;
627 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
628 info
->saved_regs
[0].addr
= 2;
629 info
->saved_regs
[1].addr
= 1;
632 else if (memcmp (img
+ 2, prologue
, sizeof (img
) - 2) == 0)
634 info
->prologue_type
= AVR_PROLOGUE_SIG
;
635 vpc
+= sizeof (img
) - 2;
636 info
->saved_regs
[AVR_SREG_REGNUM
].addr
= 3;
637 info
->saved_regs
[0].addr
= 2;
638 info
->saved_regs
[1].addr
= 1;
643 /* First stage of the prologue scanning.
644 Scan pushes (saved registers) */
646 for (; vpc
< AVR_MAX_PROLOGUE_SIZE
; vpc
+= 2)
648 insn
= EXTRACT_INSN (&prologue
[vpc
]);
649 if ((insn
& 0xfe0f) == 0x920f) /* push rXX */
651 /* Bits 4-9 contain a mask for registers R0-R32. */
652 int regno
= (insn
& 0x1f0) >> 4;
654 info
->saved_regs
[regno
].addr
= info
->size
;
661 if (vpc
>= AVR_MAX_PROLOGUE_SIZE
)
662 fprintf_unfiltered (gdb_stderr
,
663 _("Hit end of prologue while scanning pushes\n"));
665 /* Second stage of the prologue scanning.
670 if (scan_stage
== 1 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
672 unsigned char img
[] = {
673 0xcd, 0xb7, /* in r28,__SP_L__ */
674 0xde, 0xb7 /* in r29,__SP_H__ */
676 unsigned short insn1
;
678 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
685 /* Third stage of the prologue scanning. (Really two stages)
687 sbiw r28,XX or subi r28,lo8(XX)
689 in __tmp_reg__,__SREG__
692 out __SREG__,__tmp_reg__
695 if (scan_stage
== 2 && vpc
< AVR_MAX_PROLOGUE_SIZE
)
698 unsigned char img
[] = {
699 0x0f, 0xb6, /* in r0,0x3f */
700 0xf8, 0x94, /* cli */
701 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
702 0x0f, 0xbe, /* out 0x3f,r0 ; SREG */
703 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
705 unsigned char img_sig
[] = {
706 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
707 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
709 unsigned char img_int
[] = {
710 0xf8, 0x94, /* cli */
711 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
712 0x78, 0x94, /* sei */
713 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
716 insn
= EXTRACT_INSN (&prologue
[vpc
]);
718 if ((insn
& 0xff30) == 0x9720) /* sbiw r28,XXX */
719 locals_size
= (insn
& 0xf) | ((insn
& 0xc0) >> 2);
720 else if ((insn
& 0xf0f0) == 0x50c0) /* subi r28,lo8(XX) */
722 locals_size
= (insn
& 0xf) | ((insn
& 0xf00) >> 4);
723 insn
= EXTRACT_INSN (&prologue
[vpc
]);
725 locals_size
+= ((insn
& 0xf) | ((insn
& 0xf00) >> 4) << 8);
730 /* Scan the last part of the prologue. May not be present for interrupt
731 or signal handler functions, which is why we set the prologue type
732 when we saw the beginning of the prologue previously. */
734 if (memcmp (prologue
+ vpc
, img_sig
, sizeof (img_sig
)) == 0)
736 vpc
+= sizeof (img_sig
);
738 else if (memcmp (prologue
+ vpc
, img_int
, sizeof (img_int
)) == 0)
740 vpc
+= sizeof (img_int
);
742 if (memcmp (prologue
+ vpc
, img
, sizeof (img
)) == 0)
744 info
->prologue_type
= AVR_PROLOGUE_NORMAL
;
748 info
->size
+= locals_size
;
750 return pc
+ avr_scan_arg_moves (vpc
, prologue
);
753 /* If we got this far, we could not scan the prologue, so just return the pc
754 of the frame plus an adjustment for argument move insns. */
756 return pc
+ avr_scan_arg_moves (vpc
, prologue
);;
760 avr_skip_prologue (CORE_ADDR pc
)
762 CORE_ADDR func_addr
, func_end
;
763 CORE_ADDR prologue_end
= pc
;
765 /* See what the symbol table says */
767 if (find_pc_partial_function (pc
, NULL
, &func_addr
, &func_end
))
769 struct symtab_and_line sal
;
770 struct avr_unwind_cache info
= {0};
771 struct trad_frame_saved_reg saved_regs
[AVR_NUM_REGS
];
773 info
.saved_regs
= saved_regs
;
775 /* Need to run the prologue scanner to figure out if the function has a
776 prologue and possibly skip over moving arguments passed via registers
777 to other registers. */
779 prologue_end
= avr_scan_prologue (pc
, &info
);
781 if (info
.prologue_type
== AVR_PROLOGUE_NONE
)
785 sal
= find_pc_line (func_addr
, 0);
787 if (sal
.line
!= 0 && sal
.end
< func_end
)
792 /* Either we didn't find the start of this function (nothing we can do),
793 or there's no line info, or the line after the prologue is after
794 the end of the function (there probably isn't a prologue). */
799 /* Not all avr devices support the BREAK insn. Those that don't should treat
800 it as a NOP. Thus, it should be ok. Since the avr is currently a remote
801 only target, this shouldn't be a problem (I hope). TRoth/2003-05-14 */
803 static const unsigned char *
804 avr_breakpoint_from_pc (CORE_ADDR
* pcptr
, int *lenptr
)
806 static unsigned char avr_break_insn
[] = { 0x98, 0x95 };
807 *lenptr
= sizeof (avr_break_insn
);
808 return avr_break_insn
;
811 /* Given a return value in `regbuf' with a type `valtype',
812 extract and copy its value into `valbuf'.
814 Return values are always passed via registers r25:r24:... */
817 avr_extract_return_value (struct type
*type
, struct regcache
*regcache
,
823 if (TYPE_LENGTH (type
) == 1)
825 regcache_cooked_read_unsigned (regcache
, 24, &c
);
826 store_unsigned_integer (valbuf
, 1, c
);
831 /* The MSB of the return value is always in r25, calculate which
832 register holds the LSB. */
833 int lsb_reg
= 25 - TYPE_LENGTH (type
) + 1;
835 for (i
=0; i
< TYPE_LENGTH (type
); i
++)
837 regcache_cooked_read (regcache
, lsb_reg
+ i
,
838 (bfd_byte
*) valbuf
+ i
);
843 /* Put here the code to store, into fi->saved_regs, the addresses of
844 the saved registers of frame described by FRAME_INFO. This
845 includes special registers such as pc and fp saved in special ways
846 in the stack frame. sp is even more special: the address we return
847 for it IS the sp for the next frame. */
849 struct avr_unwind_cache
*
850 avr_frame_unwind_cache (struct frame_info
*next_frame
,
851 void **this_prologue_cache
)
856 struct avr_unwind_cache
*info
;
859 if ((*this_prologue_cache
))
860 return (*this_prologue_cache
);
862 info
= FRAME_OBSTACK_ZALLOC (struct avr_unwind_cache
);
863 (*this_prologue_cache
) = info
;
864 info
->saved_regs
= trad_frame_alloc_saved_regs (next_frame
);
867 info
->prologue_type
= AVR_PROLOGUE_NONE
;
869 pc
= frame_func_unwind (next_frame
, NORMAL_FRAME
);
871 if ((pc
> 0) && (pc
< frame_pc_unwind (next_frame
)))
872 avr_scan_prologue (pc
, info
);
874 if ((info
->prologue_type
!= AVR_PROLOGUE_NONE
)
875 && (info
->prologue_type
!= AVR_PROLOGUE_MAIN
))
877 ULONGEST high_base
; /* High byte of FP */
879 /* The SP was moved to the FP. This indicates that a new frame
880 was created. Get THIS frame's FP value by unwinding it from
882 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
, &this_base
);
883 frame_unwind_unsigned_register (next_frame
, AVR_FP_REGNUM
+1, &high_base
);
884 this_base
+= (high_base
<< 8);
886 /* The FP points at the last saved register. Adjust the FP back
887 to before the first saved register giving the SP. */
888 prev_sp
= this_base
+ info
->size
;
892 /* Assume that the FP is this frame's SP but with that pushed
893 stack space added back. */
894 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &this_base
);
895 prev_sp
= this_base
+ info
->size
;
898 /* Add 1 here to adjust for the post-decrement nature of the push
900 info
->prev_sp
= avr_make_saddr (prev_sp
+1);
902 info
->base
= avr_make_saddr (this_base
);
904 /* Adjust all the saved registers so that they contain addresses and not
906 for (i
= 0; i
< gdbarch_num_regs (current_gdbarch
) - 1; i
++)
907 if (info
->saved_regs
[i
].addr
)
909 info
->saved_regs
[i
].addr
= (info
->prev_sp
- info
->saved_regs
[i
].addr
);
912 /* Except for the main and startup code, the return PC is always saved on
913 the stack and is at the base of the frame. */
915 if (info
->prologue_type
!= AVR_PROLOGUE_MAIN
)
917 info
->saved_regs
[AVR_PC_REGNUM
].addr
= info
->prev_sp
;
920 /* The previous frame's SP needed to be computed. Save the computed
922 trad_frame_set_value (info
->saved_regs
, AVR_SP_REGNUM
, info
->prev_sp
+1);
928 avr_unwind_pc (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
932 frame_unwind_unsigned_register (next_frame
, AVR_PC_REGNUM
, &pc
);
934 return avr_make_iaddr (pc
);
938 avr_unwind_sp (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
942 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &sp
);
944 return avr_make_saddr (sp
);
947 /* Given a GDB frame, determine the address of the calling function's
948 frame. This will be used to create a new GDB frame struct. */
951 avr_frame_this_id (struct frame_info
*next_frame
,
952 void **this_prologue_cache
,
953 struct frame_id
*this_id
)
955 struct avr_unwind_cache
*info
956 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
961 /* The FUNC is easy. */
962 func
= frame_func_unwind (next_frame
, NORMAL_FRAME
);
964 /* Hopefully the prologue analysis either correctly determined the
965 frame's base (which is the SP from the previous frame), or set
966 that base to "NULL". */
967 base
= info
->prev_sp
;
971 id
= frame_id_build (base
, func
);
976 avr_frame_prev_register (struct frame_info
*next_frame
,
977 void **this_prologue_cache
,
978 int regnum
, int *optimizedp
,
979 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
980 int *realnump
, gdb_byte
*bufferp
)
982 struct avr_unwind_cache
*info
983 = avr_frame_unwind_cache (next_frame
, this_prologue_cache
);
985 if (regnum
== AVR_PC_REGNUM
)
987 if (trad_frame_addr_p (info
->saved_regs
, regnum
))
990 *lvalp
= lval_memory
;
991 *addrp
= info
->saved_regs
[regnum
].addr
;
995 /* Reading the return PC from the PC register is slightly
996 abnormal. register_size(AVR_PC_REGNUM) says it is 4 bytes,
997 but in reality, only two bytes (3 in upcoming mega256) are
1000 Also, note that the value on the stack is an addr to a word
1001 not a byte, so we will need to multiply it by two at some
1004 And to confuse matters even more, the return address stored
1005 on the stack is in big endian byte order, even though most
1006 everything else about the avr is little endian. Ick! */
1008 /* FIXME: number of bytes read here will need updated for the
1009 mega256 when it is available. */
1013 unsigned char buf
[2];
1015 read_memory (info
->saved_regs
[regnum
].addr
, buf
, 2);
1017 /* Convert the PC read from memory as a big-endian to
1018 little-endian order. */
1023 pc
= (extract_unsigned_integer (buf
, 2) * 2);
1024 store_unsigned_integer (bufferp
,
1025 register_size (current_gdbarch
, regnum
),
1031 trad_frame_get_prev_register (next_frame
, info
->saved_regs
, regnum
,
1032 optimizedp
, lvalp
, addrp
, realnump
, bufferp
);
1035 static const struct frame_unwind avr_frame_unwind
= {
1038 avr_frame_prev_register
1041 const struct frame_unwind
*
1042 avr_frame_sniffer (struct frame_info
*next_frame
)
1044 return &avr_frame_unwind
;
1048 avr_frame_base_address (struct frame_info
*next_frame
, void **this_cache
)
1050 struct avr_unwind_cache
*info
1051 = avr_frame_unwind_cache (next_frame
, this_cache
);
1056 static const struct frame_base avr_frame_base
= {
1058 avr_frame_base_address
,
1059 avr_frame_base_address
,
1060 avr_frame_base_address
1063 /* Assuming NEXT_FRAME->prev is a dummy, return the frame ID of that
1064 dummy frame. The frame ID's base needs to match the TOS value
1065 saved by save_dummy_frame_tos(), and the PC match the dummy frame's
1068 static struct frame_id
1069 avr_unwind_dummy_id (struct gdbarch
*gdbarch
, struct frame_info
*next_frame
)
1073 frame_unwind_unsigned_register (next_frame
, AVR_SP_REGNUM
, &base
);
1074 return frame_id_build (avr_make_saddr (base
), frame_pc_unwind (next_frame
));
1077 /* When arguments must be pushed onto the stack, they go on in reverse
1078 order. The below implements a FILO (stack) to do this. */
1083 struct stack_item
*prev
;
1087 static struct stack_item
*
1088 push_stack_item (struct stack_item
*prev
, const bfd_byte
*contents
, int len
)
1090 struct stack_item
*si
;
1091 si
= xmalloc (sizeof (struct stack_item
));
1092 si
->data
= xmalloc (len
);
1095 memcpy (si
->data
, contents
, len
);
1099 static struct stack_item
*pop_stack_item (struct stack_item
*si
);
1100 static struct stack_item
*
1101 pop_stack_item (struct stack_item
*si
)
1103 struct stack_item
*dead
= si
;
1110 /* Setup the function arguments for calling a function in the inferior.
1112 On the AVR architecture, there are 18 registers (R25 to R8) which are
1113 dedicated for passing function arguments. Up to the first 18 arguments
1114 (depending on size) may go into these registers. The rest go on the stack.
1116 All arguments are aligned to start in even-numbered registers (odd-sized
1117 arguments, including char, have one free register above them). For example,
1118 an int in arg1 and a char in arg2 would be passed as such:
1123 Arguments that are larger than 2 bytes will be split between two or more
1124 registers as available, but will NOT be split between a register and the
1125 stack. Arguments that go onto the stack are pushed last arg first (this is
1126 similar to the d10v). */
1128 /* NOTE: TRoth/2003-06-17: The rest of this comment is old looks to be
1131 An exceptional case exists for struct arguments (and possibly other
1132 aggregates such as arrays) -- if the size is larger than WORDSIZE bytes but
1133 not a multiple of WORDSIZE bytes. In this case the argument is never split
1134 between the registers and the stack, but instead is copied in its entirety
1135 onto the stack, AND also copied into as many registers as there is room
1136 for. In other words, space in registers permitting, two copies of the same
1137 argument are passed in. As far as I can tell, only the one on the stack is
1138 used, although that may be a function of the level of compiler
1139 optimization. I suspect this is a compiler bug. Arguments of these odd
1140 sizes are left-justified within the word (as opposed to arguments smaller
1141 than WORDSIZE bytes, which are right-justified).
1143 If the function is to return an aggregate type such as a struct, the caller
1144 must allocate space into which the callee will copy the return value. In
1145 this case, a pointer to the return value location is passed into the callee
1146 in register R0, which displaces one of the other arguments passed in via
1147 registers R0 to R2. */
1150 avr_push_dummy_call (struct gdbarch
*gdbarch
, struct value
*function
,
1151 struct regcache
*regcache
, CORE_ADDR bp_addr
,
1152 int nargs
, struct value
**args
, CORE_ADDR sp
,
1153 int struct_return
, CORE_ADDR struct_addr
)
1156 unsigned char buf
[2];
1157 CORE_ADDR return_pc
= avr_convert_iaddr_to_raw (bp_addr
);
1158 int regnum
= AVR_ARGN_REGNUM
;
1159 struct stack_item
*si
= NULL
;
1162 /* FIXME: TRoth/2003-06-18: Not sure what to do when returning a struct. */
1165 fprintf_unfiltered (gdb_stderr
, "struct_return: 0x%lx\n", struct_addr
);
1166 write_register (argreg
--, struct_addr
& 0xff);
1167 write_register (argreg
--, (struct_addr
>>8) & 0xff);
1171 for (i
= 0; i
< nargs
; i
++)
1175 struct value
*arg
= args
[i
];
1176 struct type
*type
= check_typedef (value_type (arg
));
1177 const bfd_byte
*contents
= value_contents (arg
);
1178 int len
= TYPE_LENGTH (type
);
1180 /* Calculate the potential last register needed. */
1181 last_regnum
= regnum
- (len
+ (len
& 1));
1183 /* If there are registers available, use them. Once we start putting
1184 stuff on the stack, all subsequent args go on stack. */
1185 if ((si
== NULL
) && (last_regnum
>= 8))
1189 /* Skip a register for odd length args. */
1193 val
= extract_unsigned_integer (contents
, len
);
1194 for (j
=0; j
<len
; j
++)
1196 regcache_cooked_write_unsigned (regcache
, regnum
--,
1197 val
>> (8*(len
-j
-1)));
1200 /* No registers available, push the args onto the stack. */
1203 /* From here on, we don't care about regnum. */
1204 si
= push_stack_item (si
, contents
, len
);
1208 /* Push args onto the stack. */
1212 /* Add 1 to sp here to account for post decr nature of pushes. */
1213 write_memory (sp
+1, si
->data
, si
->len
);
1214 si
= pop_stack_item (si
);
1217 /* Set the return address. For the avr, the return address is the BP_ADDR.
1218 Need to push the return address onto the stack noting that it needs to be
1219 in big-endian order on the stack. */
1220 buf
[0] = (return_pc
>> 8) & 0xff;
1221 buf
[1] = return_pc
& 0xff;
1224 write_memory (sp
+1, buf
, 2); /* Add one since pushes are post decr ops. */
1226 /* Finally, update the SP register. */
1227 regcache_cooked_write_unsigned (regcache
, AVR_SP_REGNUM
,
1228 avr_convert_saddr_to_raw (sp
));
1233 /* Initialize the gdbarch structure for the AVR's. */
1235 static struct gdbarch
*
1236 avr_gdbarch_init (struct gdbarch_info info
, struct gdbarch_list
*arches
)
1238 struct gdbarch
*gdbarch
;
1239 struct gdbarch_tdep
*tdep
;
1241 /* Find a candidate among the list of pre-declared architectures. */
1242 arches
= gdbarch_list_lookup_by_info (arches
, &info
);
1244 return arches
->gdbarch
;
1246 /* None found, create a new architecture from the information provided. */
1247 tdep
= XMALLOC (struct gdbarch_tdep
);
1248 gdbarch
= gdbarch_alloc (&info
, tdep
);
1250 /* If we ever need to differentiate the device types, do it here. */
1251 switch (info
.bfd_arch_info
->mach
)
1261 set_gdbarch_short_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1262 set_gdbarch_int_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1263 set_gdbarch_long_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1264 set_gdbarch_long_long_bit (gdbarch
, 8 * TARGET_CHAR_BIT
);
1265 set_gdbarch_ptr_bit (gdbarch
, 2 * TARGET_CHAR_BIT
);
1266 set_gdbarch_addr_bit (gdbarch
, 32);
1268 set_gdbarch_float_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1269 set_gdbarch_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1270 set_gdbarch_long_double_bit (gdbarch
, 4 * TARGET_CHAR_BIT
);
1272 set_gdbarch_float_format (gdbarch
, floatformats_ieee_single
);
1273 set_gdbarch_double_format (gdbarch
, floatformats_ieee_single
);
1274 set_gdbarch_long_double_format (gdbarch
, floatformats_ieee_single
);
1276 set_gdbarch_read_pc (gdbarch
, avr_read_pc
);
1277 set_gdbarch_write_pc (gdbarch
, avr_write_pc
);
1279 set_gdbarch_num_regs (gdbarch
, AVR_NUM_REGS
);
1281 set_gdbarch_sp_regnum (gdbarch
, AVR_SP_REGNUM
);
1282 set_gdbarch_pc_regnum (gdbarch
, AVR_PC_REGNUM
);
1284 set_gdbarch_register_name (gdbarch
, avr_register_name
);
1285 set_gdbarch_register_type (gdbarch
, avr_register_type
);
1287 set_gdbarch_extract_return_value (gdbarch
, avr_extract_return_value
);
1288 set_gdbarch_print_insn (gdbarch
, print_insn_avr
);
1290 set_gdbarch_push_dummy_call (gdbarch
, avr_push_dummy_call
);
1292 set_gdbarch_address_to_pointer (gdbarch
, avr_address_to_pointer
);
1293 set_gdbarch_pointer_to_address (gdbarch
, avr_pointer_to_address
);
1295 set_gdbarch_skip_prologue (gdbarch
, avr_skip_prologue
);
1296 set_gdbarch_inner_than (gdbarch
, core_addr_lessthan
);
1298 set_gdbarch_breakpoint_from_pc (gdbarch
, avr_breakpoint_from_pc
);
1300 frame_unwind_append_sniffer (gdbarch
, avr_frame_sniffer
);
1301 frame_base_set_default (gdbarch
, &avr_frame_base
);
1303 set_gdbarch_unwind_dummy_id (gdbarch
, avr_unwind_dummy_id
);
1305 set_gdbarch_unwind_pc (gdbarch
, avr_unwind_pc
);
1306 set_gdbarch_unwind_sp (gdbarch
, avr_unwind_sp
);
1311 /* Send a query request to the avr remote target asking for values of the io
1312 registers. If args parameter is not NULL, then the user has requested info
1313 on a specific io register [This still needs implemented and is ignored for
1314 now]. The query string should be one of these forms:
1316 "Ravr.io_reg" -> reply is "NN" number of io registers
1318 "Ravr.io_reg:addr,len" where addr is first register and len is number of
1319 registers to be read. The reply should be "<NAME>,VV;" for each io register
1320 where, <NAME> is a string, and VV is the hex value of the register.
1322 All io registers are 8-bit. */
1325 avr_io_reg_read_command (char *args
, int from_tty
)
1331 unsigned int nreg
= 0;
1335 /* Find out how many io registers the target has. */
1336 bufsiz
= target_read_alloc (¤t_target
, TARGET_OBJECT_AVR
,
1337 "avr.io_reg", &buf
);
1341 fprintf_unfiltered (gdb_stderr
,
1342 _("ERR: info io_registers NOT supported "
1343 "by current target\n"));
1347 if (sscanf (buf
, "%x", &nreg
) != 1)
1349 fprintf_unfiltered (gdb_stderr
,
1350 _("Error fetching number of io registers\n"));
1357 reinitialize_more_filter ();
1359 printf_unfiltered (_("Target has %u io registers:\n\n"), nreg
);
1361 /* only fetch up to 8 registers at a time to keep the buffer small */
1364 for (i
= 0; i
< nreg
; i
+= step
)
1366 /* how many registers this round? */
1369 j
= nreg
- i
; /* last block is less than 8 registers */
1371 snprintf (query
, sizeof (query
) - 1, "avr.io_reg:%x,%x", i
, j
);
1372 bufsiz
= target_read_alloc (¤t_target
, TARGET_OBJECT_AVR
,
1376 for (k
= i
; k
< (i
+ j
); k
++)
1378 if (sscanf (p
, "%[^,],%x;", query
, &val
) == 2)
1380 printf_filtered ("[%02x] %-15s : %02x\n", k
, query
, val
);
1381 while ((*p
!= ';') && (*p
!= '\0'))
1383 p
++; /* skip over ';' */
1393 extern initialize_file_ftype _initialize_avr_tdep
; /* -Wmissing-prototypes */
1396 _initialize_avr_tdep (void)
1398 register_gdbarch_init (bfd_arch_avr
, avr_gdbarch_init
);
1400 /* Add a new command to allow the user to query the avr remote target for
1401 the values of the io space registers in a saner way than just using
1404 /* FIXME: TRoth/2002-02-18: This should probably be changed to 'info avr
1405 io_registers' to signify it is not available on other platforms. */
1407 add_cmd ("io_registers", class_info
, avr_io_reg_read_command
,
1408 _("query remote avr target for io space register values"),