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@verinet.com */
24 /* Portions of this file were taken from the original gdb-4.18 patch developed
25 by Denis Chertykov, denisc@overta.ru */
32 #include "arch-utils.h"
34 #include "gdb_string.h"
38 (AVR micros are pure Harvard Architecture processors.)
40 The AVR family of microcontrollers have three distinctly different memory
41 spaces: flash, sram and eeprom. The flash is 16 bits wide and is used for
42 the most part to store program instructions. The sram is 8 bits wide and is
43 used for the stack and the heap. Some devices lack sram and some can have
44 an additional external sram added on as a peripheral.
46 The eeprom is 8 bits wide and is used to store data when the device is
47 powered down. Eeprom is not directly accessible, it can only be accessed
48 via io-registers using a special algorithm. Accessing eeprom via gdb's
49 remote serial protocol ('m' or 'M' packets) looks difficult to do and is
50 not included at this time.
52 [The eeprom could be read manually via ``x/b <eaddr + AVR_EMEM_START>'' or
53 written using ``set {unsigned char}<eaddr + AVR_EMEM_START>''. For this to
54 work, the remote target must be able to handle eeprom accesses and perform
55 the address translation.]
57 All three memory spaces have physical addresses beginning at 0x0. In
58 addition, the flash is addressed by gcc/binutils/gdb with respect to 8 bit
59 bytes instead of the 16 bit wide words used by the real device for the
62 In order for remote targets to work correctly, extra bits must be added to
63 addresses before they are send to the target or received from the target
64 via the remote serial protocol. The extra bits are the MSBs and are used to
65 decode which memory space the address is referring to. */
68 #define XMALLOC(TYPE) ((TYPE*) xmalloc (sizeof (TYPE)))
71 #define EXTRACT_INSN(addr) extract_unsigned_integer(addr,2)
73 /* Constants: prefixed with AVR_ to avoid name space clashes */
87 AVR_NUM_REGS = 32 + 1 /*SREG*/ + 1 /*SP*/ + 1 /*PC*/,
88 AVR_NUM_REG_BYTES = 32 + 1 /*SREG*/ + 2 /*SP*/ + 4 /*PC*/,
90 AVR_PC_REG_INDEX = 35, /* index into array of registers */
92 AVR_MAX_PROLOGUE_SIZE = 56, /* bytes */
94 /* Count of pushed registers. From r2 to r17 (inclusively), r28, r29 */
97 /* Number of the last pushed register. r17 for current avr-gcc */
98 AVR_LAST_PUSHED_REGNUM = 17,
100 /* FIXME: TRoth/2002-01-??: Can we shift all these memory masks left 8
101 bits? Do these have to match the bfd vma values?. It sure would make
102 things easier in the future if they didn't need to match.
104 Note: I chose these values so as to be consistent with bfd vma
107 TRoth/2002-04-08: There is already a conflict with very large programs
108 in the mega128. The mega128 has 128K instruction bytes (64K words),
109 thus the Most Significant Bit is 0x10000 which gets masked off my
112 The problem manifests itself when trying to set a breakpoint in a
113 function which resides in the upper half of the instruction space and
114 thus requires a 17-bit address.
116 For now, I've just removed the EEPROM mask and changed AVR_MEM_MASK
117 from 0x00ff0000 to 0x00f00000. Eeprom is not accessible from gdb yet,
118 but could be for some remote targets by just adding the correct offset
119 to the address and letting the remote target handle the low-level
120 details of actually accessing the eeprom. */
122 AVR_IMEM_START = 0x00000000, /* INSN memory */
123 AVR_SMEM_START = 0x00800000, /* SRAM memory */
125 /* No eeprom mask defined */
126 AVR_MEM_MASK = 0x00f00000, /* mask to determine memory space */
128 AVR_EMEM_START = 0x00810000, /* EEPROM memory */
129 AVR_MEM_MASK = 0x00ff0000, /* mask to determine memory space */
133 /* Any function with a frame looks like this
134 ....... <-SP POINTS HERE
135 LOCALS1 <-FP POINTS HERE
144 struct frame_extra_info
147 CORE_ADDR args_pointer;
156 /* FIXME: TRoth: is there anything to put here? */
160 /* Lookup the name of a register given it's number. */
163 avr_register_name (int regnum)
165 static char *register_names[] = {
166 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
167 "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
168 "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
169 "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
174 if (regnum >= (sizeof (register_names) / sizeof (*register_names)))
176 return register_names[regnum];
179 /* Index within `registers' of the first byte of the space for
183 avr_register_byte (int regnum)
185 if (regnum < AVR_PC_REGNUM)
188 return AVR_PC_REG_INDEX;
191 /* Number of bytes of storage in the actual machine representation for
195 avr_register_raw_size (int regnum)
209 /* Number of bytes of storage in the program's representation
213 avr_register_virtual_size (int regnum)
215 return TYPE_LENGTH (REGISTER_VIRTUAL_TYPE (regnum));
218 /* Return the GDB type object for the "standard" data type
219 of data in register N. */
222 avr_register_virtual_type (int regnum)
227 return builtin_type_unsigned_long;
229 return builtin_type_unsigned_short;
231 return builtin_type_unsigned_char;
235 /* Instruction address checks and convertions. */
238 avr_make_iaddr (CORE_ADDR x)
240 return ((x) | AVR_IMEM_START);
244 avr_iaddr_p (CORE_ADDR x)
246 return (((x) & AVR_MEM_MASK) == AVR_IMEM_START);
249 /* FIXME: TRoth: Really need to use a larger mask for instructions. Some
250 devices are already up to 128KBytes of flash space.
252 TRoth/2002-04-8: See comment above where AVR_IMEM_START is defined. */
255 avr_convert_iaddr_to_raw (CORE_ADDR x)
257 return ((x) & 0xffffffff);
260 /* SRAM address checks and convertions. */
263 avr_make_saddr (CORE_ADDR x)
265 return ((x) | AVR_SMEM_START);
269 avr_saddr_p (CORE_ADDR x)
271 return (((x) & AVR_MEM_MASK) == AVR_SMEM_START);
275 avr_convert_saddr_to_raw (CORE_ADDR x)
277 return ((x) & 0xffffffff);
280 /* EEPROM address checks and convertions. I don't know if these will ever
281 actually be used, but I've added them just the same. TRoth */
283 /* TRoth/2002-04-08: Commented out for now to allow fix for problem with large
284 programs in the mega128. */
286 /* static CORE_ADDR */
287 /* avr_make_eaddr (CORE_ADDR x) */
289 /* return ((x) | AVR_EMEM_START); */
293 /* avr_eaddr_p (CORE_ADDR x) */
295 /* return (((x) & AVR_MEM_MASK) == AVR_EMEM_START); */
298 /* static CORE_ADDR */
299 /* avr_convert_eaddr_to_raw (CORE_ADDR x) */
301 /* return ((x) & 0xffffffff); */
304 /* Convert from address to pointer and vice-versa. */
307 avr_address_to_pointer (struct type *type, void *buf, CORE_ADDR addr)
309 /* Is it a code address? */
310 if (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC
311 || TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_METHOD)
313 store_unsigned_integer (buf, TYPE_LENGTH (type),
314 avr_convert_iaddr_to_raw (addr));
318 /* Strip off any upper segment bits. */
319 store_unsigned_integer (buf, TYPE_LENGTH (type),
320 avr_convert_saddr_to_raw (addr));
325 avr_pointer_to_address (struct type *type, const void *buf)
327 CORE_ADDR addr = extract_address (buf, TYPE_LENGTH (type));
329 if (TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type)))
331 fprintf_unfiltered (gdb_stderr, "CODE_SPACE ---->> ptr->addr: 0x%lx\n",
333 fprintf_unfiltered (gdb_stderr,
334 "+++ If you see this, please send me an email <troth@verinet.com>\n");
337 /* Is it a code address? */
338 if (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC
339 || TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_METHOD
340 || TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type)))
341 return avr_make_iaddr (addr);
343 return avr_make_saddr (addr);
347 avr_read_pc (ptid_t ptid)
353 save_ptid = inferior_ptid;
354 inferior_ptid = ptid;
355 pc = (int) read_register (AVR_PC_REGNUM);
356 inferior_ptid = save_ptid;
357 retval = avr_make_iaddr (pc);
362 avr_write_pc (CORE_ADDR val, ptid_t ptid)
366 save_ptid = inferior_ptid;
367 inferior_ptid = ptid;
368 write_register (AVR_PC_REGNUM, avr_convert_iaddr_to_raw (val));
369 inferior_ptid = save_ptid;
375 return (avr_make_saddr (read_register (AVR_SP_REGNUM)));
379 avr_write_sp (CORE_ADDR val)
381 write_register (AVR_SP_REGNUM, avr_convert_saddr_to_raw (val));
387 return (avr_make_saddr (read_register (AVR_FP_REGNUM)));
390 /* Translate a GDB virtual ADDR/LEN into a format the remote target
391 understands. Returns number of bytes that can be transfered
392 starting at TARG_ADDR. Return ZERO if no bytes can be transfered
393 (segmentation fault).
395 TRoth/2002-04-08: Could this be used to check for dereferencing an invalid
399 avr_remote_translate_xfer_address (CORE_ADDR memaddr, int nr_bytes,
400 CORE_ADDR *targ_addr, int *targ_len)
405 /* FIXME: TRoth: Do nothing for now. Will need to examine memaddr at this
406 point and see if the high bit are set with the masks that we want. */
408 *targ_addr = memaddr;
409 *targ_len = nr_bytes;
412 /* Function pointers obtained from the target are half of what gdb expects so
416 avr_convert_from_func_ptr_addr (CORE_ADDR addr)
421 /* avr_scan_prologue is also used as the frame_init_saved_regs().
423 Put here the code to store, into fi->saved_regs, the addresses of
424 the saved registers of frame described by FRAME_INFO. This
425 includes special registers such as pc and fp saved in special ways
426 in the stack frame. sp is even more special: the address we return
427 for it IS the sp for the next frame. */
429 /* Function: avr_scan_prologue (helper function for avr_init_extra_frame_info)
430 This function decodes a AVR function prologue to determine:
431 1) the size of the stack frame
432 2) which registers are saved on it
433 3) the offsets of saved regs
434 This information is stored in the "extra_info" field of the frame_info.
436 A typical AVR function prologue might look like this:
442 sbiw r28,<LOCALS_SIZE>
443 in __tmp_reg__,__SREG__
446 out __SREG__,__tmp_reg__
449 A `-mcall-prologues' prologue look like this:
450 ldi r26,<LOCALS_SIZE>
451 ldi r27,<LOCALS_SIZE>/265
452 ldi r30,pm_lo8(.L_foo_body)
453 ldi r31,pm_hi8(.L_foo_body)
454 rjmp __prologue_saves__+RRR
458 avr_scan_prologue (struct frame_info *fi)
460 CORE_ADDR prologue_start;
461 CORE_ADDR prologue_end;
467 struct minimal_symbol *msymbol;
469 unsigned char prologue[AVR_MAX_PROLOGUE_SIZE];
472 fi->extra_info->framereg = AVR_SP_REGNUM;
474 if (find_pc_partial_function
475 (get_frame_pc (fi), &name, &prologue_start, &prologue_end))
477 struct symtab_and_line sal = find_pc_line (prologue_start, 0);
479 if (sal.line == 0) /* no line info, use current PC */
480 prologue_end = get_frame_pc (fi);
481 else if (sal.end < prologue_end) /* next line begins after fn end */
482 prologue_end = sal.end; /* (probably means no prologue) */
485 /* We're in the boondocks: allow for */
486 /* 19 pushes, an add, and "mv fp,sp" */
487 prologue_end = prologue_start + AVR_MAX_PROLOGUE_SIZE;
489 prologue_end = min (prologue_end, get_frame_pc (fi));
491 /* Search the prologue looking for instructions that set up the
492 frame pointer, adjust the stack pointer, and save registers. */
494 fi->extra_info->framesize = 0;
495 prologue_len = prologue_end - prologue_start;
496 read_memory (prologue_start, prologue, prologue_len);
498 /* Scanning main()'s prologue
499 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
500 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
504 if (name && strcmp ("main", name) == 0 && prologue_len == 8)
507 unsigned char img[] = {
508 0xde, 0xbf, /* out __SP_H__,r29 */
509 0xcd, 0xbf /* out __SP_L__,r28 */
512 fi->extra_info->framereg = AVR_FP_REGNUM;
513 insn = EXTRACT_INSN (&prologue[vpc]);
514 /* ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>) */
515 if ((insn & 0xf0f0) == 0xe0c0)
517 locals = (insn & 0xf) | ((insn & 0x0f00) >> 4);
518 insn = EXTRACT_INSN (&prologue[vpc + 2]);
519 /* ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>) */
520 if ((insn & 0xf0f0) == 0xe0d0)
522 locals |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8;
523 if (memcmp (prologue + vpc + 4, img, sizeof (img)) == 0)
525 deprecated_update_frame_base_hack (fi, locals);
527 fi->extra_info->is_main = 1;
534 /* Scanning `-mcall-prologues' prologue
535 FIXME: mega prologue have a 12 bytes long */
537 while (prologue_len <= 12) /* I'm use while to avoit many goto's */
543 insn = EXTRACT_INSN (&prologue[vpc]);
544 /* ldi r26,<LOCALS_SIZE> */
545 if ((insn & 0xf0f0) != 0xe0a0)
547 loc_size = (insn & 0xf) | ((insn & 0x0f00) >> 4);
549 insn = EXTRACT_INSN (&prologue[vpc + 2]);
550 /* ldi r27,<LOCALS_SIZE> / 256 */
551 if ((insn & 0xf0f0) != 0xe0b0)
553 loc_size |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8;
555 insn = EXTRACT_INSN (&prologue[vpc + 4]);
556 /* ldi r30,pm_lo8(.L_foo_body) */
557 if ((insn & 0xf0f0) != 0xe0e0)
559 body_addr = (insn & 0xf) | ((insn & 0x0f00) >> 4);
561 insn = EXTRACT_INSN (&prologue[vpc + 6]);
562 /* ldi r31,pm_hi8(.L_foo_body) */
563 if ((insn & 0xf0f0) != 0xe0f0)
565 body_addr |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8;
567 if (body_addr != (prologue_start + 10) / 2)
570 msymbol = lookup_minimal_symbol ("__prologue_saves__", NULL, NULL);
574 /* FIXME: prologue for mega have a JMP instead of RJMP */
575 insn = EXTRACT_INSN (&prologue[vpc + 8]);
576 /* rjmp __prologue_saves__+RRR */
577 if ((insn & 0xf000) != 0xc000)
580 /* Extract PC relative offset from RJMP */
581 i = (insn & 0xfff) | (insn & 0x800 ? (-1 ^ 0xfff) : 0);
582 /* Convert offset to byte addressable mode */
584 /* Destination address */
585 i += vpc + prologue_start + 10;
586 /* Resovle offset (in words) from __prologue_saves__ symbol.
587 Which is a pushes count in `-mcall-prologues' mode */
588 num_pushes = AVR_MAX_PUSHES - (i - SYMBOL_VALUE_ADDRESS (msymbol)) / 2;
590 if (num_pushes > AVR_MAX_PUSHES)
596 get_frame_saved_regs (fi)[AVR_FP_REGNUM + 1] = num_pushes;
598 get_frame_saved_regs (fi)[AVR_FP_REGNUM] = num_pushes - 1;
600 for (from = AVR_LAST_PUSHED_REGNUM + 1 - (num_pushes - 2);
601 from <= AVR_LAST_PUSHED_REGNUM; ++from)
602 get_frame_saved_regs (fi)[from] = ++i;
604 fi->extra_info->locals_size = loc_size;
605 fi->extra_info->framesize = loc_size + num_pushes;
606 fi->extra_info->framereg = AVR_FP_REGNUM;
610 /* Scan interrupt or signal function */
612 if (prologue_len >= 12)
614 unsigned char img[] = {
615 0x78, 0x94, /* sei */
616 0x1f, 0x92, /* push r1 */
617 0x0f, 0x92, /* push r0 */
618 0x0f, 0xb6, /* in r0,0x3f SREG */
619 0x0f, 0x92, /* push r0 */
620 0x11, 0x24 /* clr r1 */
622 if (memcmp (prologue, img, sizeof (img)) == 0)
625 get_frame_saved_regs (fi)[0] = 2;
626 get_frame_saved_regs (fi)[1] = 1;
627 fi->extra_info->framesize += 3;
629 else if (memcmp (img + 1, prologue, sizeof (img) - 1) == 0)
631 vpc += sizeof (img) - 1;
632 get_frame_saved_regs (fi)[0] = 2;
633 get_frame_saved_regs (fi)[1] = 1;
634 fi->extra_info->framesize += 3;
638 /* First stage of the prologue scanning.
641 for (; vpc <= prologue_len; vpc += 2)
643 insn = EXTRACT_INSN (&prologue[vpc]);
644 if ((insn & 0xfe0f) == 0x920f) /* push rXX */
646 /* Bits 4-9 contain a mask for registers R0-R32. */
647 regno = (insn & 0x1f0) >> 4;
648 ++fi->extra_info->framesize;
649 get_frame_saved_regs (fi)[regno] = fi->extra_info->framesize;
656 /* Second stage of the prologue scanning.
661 if (scan_stage == 1 && vpc + 4 <= prologue_len)
663 unsigned char img[] = {
664 0xcd, 0xb7, /* in r28,__SP_L__ */
665 0xde, 0xb7 /* in r29,__SP_H__ */
667 unsigned short insn1;
669 if (memcmp (prologue + vpc, img, sizeof (img)) == 0)
672 fi->extra_info->framereg = AVR_FP_REGNUM;
677 /* Third stage of the prologue scanning. (Really two stages)
679 sbiw r28,XX or subi r28,lo8(XX)
681 in __tmp_reg__,__SREG__
684 out __SREG__,__tmp_reg__
687 if (scan_stage == 2 && vpc + 12 <= prologue_len)
690 unsigned char img[] = {
691 0x0f, 0xb6, /* in r0,0x3f */
692 0xf8, 0x94, /* cli */
693 0xcd, 0xbf, /* out 0x3d,r28 ; SPL */
694 0x0f, 0xbe, /* out 0x3f,r0 ; SREG */
695 0xde, 0xbf /* out 0x3e,r29 ; SPH */
697 unsigned char img_sig[] = {
698 0xcd, 0xbf, /* out 0x3d,r28 ; SPL */
699 0xde, 0xbf /* out 0x3e,r29 ; SPH */
701 unsigned char img_int[] = {
702 0xf8, 0x94, /* cli */
703 0xcd, 0xbf, /* out 0x3d,r28 ; SPL */
704 0x78, 0x94, /* sei */
705 0xde, 0xbf /* out 0x3e,r29 ; SPH */
708 insn = EXTRACT_INSN (&prologue[vpc]);
710 if ((insn & 0xff30) == 0x9720) /* sbiw r28,XXX */
711 locals_size = (insn & 0xf) | ((insn & 0xc0) >> 2);
712 else if ((insn & 0xf0f0) == 0x50c0) /* subi r28,lo8(XX) */
714 locals_size = (insn & 0xf) | ((insn & 0xf00) >> 4);
715 insn = EXTRACT_INSN (&prologue[vpc]);
717 locals_size += ((insn & 0xf) | ((insn & 0xf00) >> 4) << 8);
721 fi->extra_info->locals_size = locals_size;
722 fi->extra_info->framesize += locals_size;
726 /* This function actually figures out the frame address for a given pc and
727 sp. This is tricky because we sometimes don't use an explicit
728 frame pointer, and the previous stack pointer isn't necessarily recorded
729 on the stack. The only reliable way to get this info is to
730 examine the prologue. */
733 avr_init_extra_frame_info (int fromleaf, struct frame_info *fi)
738 deprecated_update_frame_pc_hack (fi, FRAME_SAVED_PC (fi->next));
740 frame_extra_info_zalloc (fi, sizeof (struct frame_extra_info));
741 frame_saved_regs_zalloc (fi);
743 fi->extra_info->return_pc = 0;
744 fi->extra_info->args_pointer = 0;
745 fi->extra_info->locals_size = 0;
746 fi->extra_info->framereg = 0;
747 fi->extra_info->framesize = 0;
748 fi->extra_info->is_main = 0;
750 avr_scan_prologue (fi);
752 if (DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), fi->frame, fi->frame))
754 /* We need to setup fi->frame here because run_stack_dummy gets it wrong
755 by assuming it's always FP. */
756 deprecated_update_frame_base_hack (fi, deprecated_read_register_dummy (get_frame_pc (fi), fi->frame,
759 else if (!fi->next) /* this is the innermost frame? */
760 deprecated_update_frame_base_hack (fi, read_register (fi->extra_info->framereg));
761 else if (fi->extra_info->is_main != 1) /* not the innermost frame, not `main' */
762 /* If we have an next frame, the callee saved it. */
764 struct frame_info *next_fi = fi->next;
765 if (fi->extra_info->framereg == AVR_SP_REGNUM)
766 deprecated_update_frame_base_hack (fi, next_fi->frame + 2 /* ret addr */ + next_fi->extra_info->framesize);
767 /* FIXME: I don't analyse va_args functions */
772 unsigned int fp_low, fp_high;
774 /* Scan all frames */
775 for (; next_fi; next_fi = next_fi->next)
777 /* look for saved AVR_FP_REGNUM */
778 if (get_frame_saved_regs (next_fi)[AVR_FP_REGNUM] && !fp)
779 fp = get_frame_saved_regs (next_fi)[AVR_FP_REGNUM];
780 /* look for saved AVR_FP_REGNUM + 1 */
781 if (get_frame_saved_regs (next_fi)[AVR_FP_REGNUM + 1] && !fp1)
782 fp1 = get_frame_saved_regs (next_fi)[AVR_FP_REGNUM + 1];
784 fp_low = (fp ? read_memory_unsigned_integer (avr_make_saddr (fp), 1)
785 : read_register (AVR_FP_REGNUM)) & 0xff;
787 (fp1 ? read_memory_unsigned_integer (avr_make_saddr (fp1), 1) :
788 read_register (AVR_FP_REGNUM + 1)) & 0xff;
789 deprecated_update_frame_base_hack (fi, fp_low | (fp_high << 8));
793 /* TRoth: Do we want to do this if we are in main? I don't think we should
794 since return_pc makes no sense when we are in main. */
796 if ((get_frame_pc (fi)) && (fi->extra_info->is_main == 0)) /* We are not in CALL_DUMMY */
801 addr = fi->frame + fi->extra_info->framesize + 1;
803 /* Return address in stack in different endianness */
805 fi->extra_info->return_pc =
806 read_memory_unsigned_integer (avr_make_saddr (addr), 1) << 8;
807 fi->extra_info->return_pc |=
808 read_memory_unsigned_integer (avr_make_saddr (addr + 1), 1);
810 /* This return address in words,
811 must be converted to the bytes address */
812 fi->extra_info->return_pc *= 2;
814 /* Resolve a pushed registers addresses */
815 for (i = 0; i < NUM_REGS; i++)
817 if (get_frame_saved_regs (fi)[i])
818 get_frame_saved_regs (fi)[i] = addr - get_frame_saved_regs (fi)[i];
823 /* Restore the machine to the state it had before the current frame was
824 created. Usually used either by the "RETURN" command, or by
825 call_function_by_hand after the dummy_frame is finished. */
832 struct frame_info *frame = get_current_frame ();
834 if (DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (frame), frame->frame, frame->frame))
836 generic_pop_dummy_frame ();
840 /* TRoth: Why only loop over 8 registers? */
842 for (regnum = 0; regnum < 8; regnum++)
844 /* Don't forget AVR_SP_REGNUM in a frame_saved_regs struct is the
845 actual value we want, not the address of the value we want. */
846 if (get_frame_saved_regs (frame)[regnum] && regnum != AVR_SP_REGNUM)
848 saddr = avr_make_saddr (get_frame_saved_regs (frame)[regnum]);
849 write_register (regnum,
850 read_memory_unsigned_integer (saddr, 1));
852 else if (get_frame_saved_regs (frame)[regnum] && regnum == AVR_SP_REGNUM)
853 write_register (regnum, frame->frame + 2);
856 /* Don't forget the update the PC too! */
857 write_pc (frame->extra_info->return_pc);
859 flush_cached_frames ();
862 /* Return the saved PC from this frame. */
865 avr_frame_saved_pc (struct frame_info *frame)
867 if (DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (frame), frame->frame, frame->frame))
868 return deprecated_read_register_dummy (get_frame_pc (frame), frame->frame,
871 return frame->extra_info->return_pc;
875 avr_saved_pc_after_call (struct frame_info *frame)
877 unsigned char m1, m2;
878 unsigned int sp = read_register (AVR_SP_REGNUM);
879 m1 = read_memory_unsigned_integer (avr_make_saddr (sp + 1), 1);
880 m2 = read_memory_unsigned_integer (avr_make_saddr (sp + 2), 1);
881 return (m2 | (m1 << 8)) * 2;
884 /* Figure out where in REGBUF the called function has left its return value.
885 Copy that into VALBUF. */
888 avr_extract_return_value (struct type *type, char *regbuf, char *valbuf)
894 len = TYPE_LENGTH (type);
899 case 2: /* (short), (int) */
900 memcpy (valbuf, regbuf + REGISTER_BYTE (24), 2);
902 case 4: /* (long), (float) */
903 memcpy (valbuf, regbuf + REGISTER_BYTE (22), 4);
905 case 8: /* (double) (doesn't seem to happen, which is good,
906 because this almost certainly isn't right. */
907 error ("I don't know how a double is returned.");
912 /* Returns the return address for a dummy. */
915 avr_call_dummy_address (void)
917 return entry_point_address ();
920 /* Place the appropriate value in the appropriate registers.
921 Primarily used by the RETURN command. */
924 avr_store_return_value (struct type *type, char *valbuf)
926 int wordsize, len, regval;
930 len = TYPE_LENGTH (type);
934 case 2: /* short, int */
935 regval = extract_address (valbuf, len);
936 write_register (0, regval);
938 case 4: /* long, float */
939 regval = extract_address (valbuf, len);
940 write_register (0, regval >> 16);
941 write_register (1, regval & 0xffff);
943 case 8: /* presumeably double, but doesn't seem to happen */
944 error ("I don't know how to return a double.");
949 /* Setup the return address for a dummy frame, as called by
950 call_function_by_hand. Only necessary when you are using an empty
954 avr_push_return_address (CORE_ADDR pc, CORE_ADDR sp)
956 unsigned char buf[2];
959 struct minimal_symbol *msymbol;
966 write_memory (sp + 1, buf, 2);
969 /* FIXME: TRoth/2002-02-18: This should probably be removed since it's a
970 left-over from Denis' original patch which used avr-mon for the target
971 instead of the generic remote target. */
972 if ((strcmp (target_shortname, "avr-mon") == 0)
973 && (msymbol = lookup_minimal_symbol ("gdb_break", NULL, NULL)))
975 mon_brk = SYMBOL_VALUE_ADDRESS (msymbol);
976 store_unsigned_integer (buf, wordsize, mon_brk / 2);
978 write_memory (sp + 1, buf + 1, 1);
979 write_memory (sp + 2, buf, 1);
986 avr_skip_prologue (CORE_ADDR pc)
988 CORE_ADDR func_addr, func_end;
989 struct symtab_and_line sal;
991 /* See what the symbol table says */
993 if (find_pc_partial_function (pc, NULL, &func_addr, &func_end))
995 sal = find_pc_line (func_addr, 0);
997 /* troth/2002-08-05: For some very simple functions, gcc doesn't
998 generate a prologue and the sal.end ends up being the 2-byte ``ret''
999 instruction at the end of the function, but func_end ends up being
1000 the address of the first instruction of the _next_ function. By
1001 adjusting func_end by 2 bytes, we can catch these functions and not
1002 return sal.end if it is the ``ret'' instruction. */
1004 if (sal.line != 0 && sal.end < (func_end-2))
1008 /* Either we didn't find the start of this function (nothing we can do),
1009 or there's no line info, or the line after the prologue is after
1010 the end of the function (there probably isn't a prologue). */
1016 avr_frame_address (struct frame_info *fi)
1018 return avr_make_saddr (fi->frame);
1021 /* Given a GDB frame, determine the address of the calling function's
1022 frame. This will be used to create a new GDB frame struct, and
1023 then INIT_EXTRA_FRAME_INFO and DEPRECATED_INIT_FRAME_PC will be
1024 called for the new frame.
1026 For us, the frame address is its stack pointer value, so we look up
1027 the function prologue to determine the caller's sp value, and return it. */
1030 avr_frame_chain (struct frame_info *frame)
1032 if (DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (frame), frame->frame, frame->frame))
1034 /* initialize the return_pc now */
1035 frame->extra_info->return_pc
1036 = deprecated_read_register_dummy (get_frame_pc (frame), frame->frame,
1038 return frame->frame;
1040 return (frame->extra_info->is_main ? 0
1041 : frame->frame + frame->extra_info->framesize + 2 /* ret addr */ );
1044 /* Store the address of the place in which to copy the structure the
1045 subroutine will return. This is called from call_function.
1047 We store structs through a pointer passed in the first Argument
1051 avr_store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
1053 write_register (0, addr);
1056 /* Extract from an array REGBUF containing the (raw) register state
1057 the address in which a function should return its structure value,
1058 as a CORE_ADDR (or an expression that can be used as one). */
1061 avr_extract_struct_value_address (char *regbuf)
1063 return (extract_address ((regbuf) + REGISTER_BYTE (0),
1064 REGISTER_RAW_SIZE (0)) | AVR_SMEM_START);
1067 /* Setup the function arguments for calling a function in the inferior.
1069 On the AVR architecture, there are 18 registers (R25 to R8) which are
1070 dedicated for passing function arguments. Up to the first 18 arguments
1071 (depending on size) may go into these registers. The rest go on the stack.
1073 Arguments that are larger than WORDSIZE bytes will be split between two or
1074 more registers as available, but will NOT be split between a register and
1077 An exceptional case exists for struct arguments (and possibly other
1078 aggregates such as arrays) -- if the size is larger than WORDSIZE bytes but
1079 not a multiple of WORDSIZE bytes. In this case the argument is never split
1080 between the registers and the stack, but instead is copied in its entirety
1081 onto the stack, AND also copied into as many registers as there is room
1082 for. In other words, space in registers permitting, two copies of the same
1083 argument are passed in. As far as I can tell, only the one on the stack is
1084 used, although that may be a function of the level of compiler
1085 optimization. I suspect this is a compiler bug. Arguments of these odd
1086 sizes are left-justified within the word (as opposed to arguments smaller
1087 than WORDSIZE bytes, which are right-justified).
1089 If the function is to return an aggregate type such as a struct, the caller
1090 must allocate space into which the callee will copy the return value. In
1091 this case, a pointer to the return value location is passed into the callee
1092 in register R0, which displaces one of the other arguments passed in via
1093 registers R0 to R2. */
1096 avr_push_arguments (int nargs, struct value **args, CORE_ADDR sp,
1097 int struct_return, CORE_ADDR struct_addr)
1099 int stack_alloc, stack_offset;
1111 /* Now make sure there's space on the stack */
1112 for (argnum = 0, stack_alloc = 0; argnum < nargs; argnum++)
1113 stack_alloc += TYPE_LENGTH (VALUE_TYPE (args[argnum]));
1114 sp -= stack_alloc; /* make room on stack for args */
1115 /* we may over-allocate a little here, but that won't hurt anything */
1118 if (struct_return) /* "struct return" pointer takes up one argreg */
1120 write_register (--argreg, struct_addr);
1123 /* Now load as many as possible of the first arguments into registers, and
1124 push the rest onto the stack. There are 3N bytes in three registers
1125 available. Loop thru args from first to last. */
1127 for (argnum = 0, stack_offset = 0; argnum < nargs; argnum++)
1129 type = VALUE_TYPE (args[argnum]);
1130 len = TYPE_LENGTH (type);
1131 val = (char *) VALUE_CONTENTS (args[argnum]);
1133 /* NOTE WELL!!!!! This is not an "else if" clause!!! That's because
1134 some *&^%$ things get passed on the stack AND in the registers! */
1136 { /* there's room in registers */
1138 regval = extract_address (val + len, wordsize);
1139 write_register (argreg--, regval);
1145 /* Initialize the gdbarch structure for the AVR's. */
1147 static struct gdbarch *
1148 avr_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
1150 /* FIXME: TRoth/2002-02-18: I have no idea if avr_call_dummy_words[] should
1151 be bigger or not. Initial testing seems to show that `call my_func()`
1152 works and backtrace from a breakpoint within the call looks correct.
1153 Admittedly, I haven't tested with more than a very simple program. */
1154 static LONGEST avr_call_dummy_words[] = { 0 };
1156 struct gdbarch *gdbarch;
1157 struct gdbarch_tdep *tdep;
1159 /* Find a candidate among the list of pre-declared architectures. */
1160 arches = gdbarch_list_lookup_by_info (arches, &info);
1162 return arches->gdbarch;
1164 /* None found, create a new architecture from the information provided. */
1165 tdep = XMALLOC (struct gdbarch_tdep);
1166 gdbarch = gdbarch_alloc (&info, tdep);
1168 /* NOTE: cagney/2002-12-06: This can be deleted when this arch is
1169 ready to unwind the PC first (see frame.c:get_prev_frame()). */
1170 set_gdbarch_deprecated_init_frame_pc (gdbarch, init_frame_pc_default);
1172 /* If we ever need to differentiate the device types, do it here. */
1173 switch (info.bfd_arch_info->mach)
1183 set_gdbarch_short_bit (gdbarch, 2 * TARGET_CHAR_BIT);
1184 set_gdbarch_int_bit (gdbarch, 2 * TARGET_CHAR_BIT);
1185 set_gdbarch_long_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1186 set_gdbarch_long_long_bit (gdbarch, 8 * TARGET_CHAR_BIT);
1187 set_gdbarch_ptr_bit (gdbarch, 2 * TARGET_CHAR_BIT);
1188 set_gdbarch_addr_bit (gdbarch, 32);
1189 set_gdbarch_bfd_vma_bit (gdbarch, 32); /* FIXME: TRoth/2002-02-18: Is this needed? */
1191 set_gdbarch_float_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1192 set_gdbarch_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1193 set_gdbarch_long_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1195 set_gdbarch_float_format (gdbarch, &floatformat_ieee_single_little);
1196 set_gdbarch_double_format (gdbarch, &floatformat_ieee_single_little);
1197 set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_single_little);
1199 set_gdbarch_read_pc (gdbarch, avr_read_pc);
1200 set_gdbarch_write_pc (gdbarch, avr_write_pc);
1201 set_gdbarch_read_fp (gdbarch, avr_read_fp);
1202 set_gdbarch_read_sp (gdbarch, avr_read_sp);
1203 set_gdbarch_write_sp (gdbarch, avr_write_sp);
1205 set_gdbarch_num_regs (gdbarch, AVR_NUM_REGS);
1207 set_gdbarch_sp_regnum (gdbarch, AVR_SP_REGNUM);
1208 set_gdbarch_fp_regnum (gdbarch, AVR_FP_REGNUM);
1209 set_gdbarch_pc_regnum (gdbarch, AVR_PC_REGNUM);
1211 set_gdbarch_register_name (gdbarch, avr_register_name);
1212 set_gdbarch_register_size (gdbarch, 1);
1213 set_gdbarch_register_bytes (gdbarch, AVR_NUM_REG_BYTES);
1214 set_gdbarch_register_byte (gdbarch, avr_register_byte);
1215 set_gdbarch_register_raw_size (gdbarch, avr_register_raw_size);
1216 set_gdbarch_max_register_raw_size (gdbarch, 4);
1217 set_gdbarch_register_virtual_size (gdbarch, avr_register_virtual_size);
1218 set_gdbarch_max_register_virtual_size (gdbarch, 4);
1219 set_gdbarch_register_virtual_type (gdbarch, avr_register_virtual_type);
1221 set_gdbarch_print_insn (gdbarch, print_insn_avr);
1223 set_gdbarch_call_dummy_address (gdbarch, avr_call_dummy_address);
1224 set_gdbarch_call_dummy_start_offset (gdbarch, 0);
1225 set_gdbarch_call_dummy_breakpoint_offset_p (gdbarch, 1);
1226 set_gdbarch_call_dummy_breakpoint_offset (gdbarch, 0);
1227 set_gdbarch_call_dummy_length (gdbarch, 0);
1228 set_gdbarch_call_dummy_p (gdbarch, 1);
1229 set_gdbarch_call_dummy_words (gdbarch, avr_call_dummy_words);
1230 set_gdbarch_call_dummy_stack_adjust_p (gdbarch, 0);
1231 set_gdbarch_fix_call_dummy (gdbarch, generic_fix_call_dummy);
1233 /* set_gdbarch_believe_pcc_promotion (gdbarch, 1); // TRoth: should this be set? */
1235 set_gdbarch_address_to_pointer (gdbarch, avr_address_to_pointer);
1236 set_gdbarch_pointer_to_address (gdbarch, avr_pointer_to_address);
1237 set_gdbarch_deprecated_extract_return_value (gdbarch, avr_extract_return_value);
1238 set_gdbarch_push_arguments (gdbarch, avr_push_arguments);
1239 set_gdbarch_push_dummy_frame (gdbarch, generic_push_dummy_frame);
1240 set_gdbarch_push_return_address (gdbarch, avr_push_return_address);
1241 set_gdbarch_pop_frame (gdbarch, avr_pop_frame);
1243 set_gdbarch_deprecated_store_return_value (gdbarch, avr_store_return_value);
1245 set_gdbarch_use_struct_convention (gdbarch, generic_use_struct_convention);
1246 set_gdbarch_store_struct_return (gdbarch, avr_store_struct_return);
1247 set_gdbarch_deprecated_extract_struct_value_address
1248 (gdbarch, avr_extract_struct_value_address);
1250 set_gdbarch_frame_init_saved_regs (gdbarch, avr_scan_prologue);
1251 set_gdbarch_init_extra_frame_info (gdbarch, avr_init_extra_frame_info);
1252 set_gdbarch_skip_prologue (gdbarch, avr_skip_prologue);
1253 /* set_gdbarch_prologue_frameless_p (gdbarch, avr_prologue_frameless_p); */
1254 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
1256 set_gdbarch_decr_pc_after_break (gdbarch, 0);
1258 set_gdbarch_function_start_offset (gdbarch, 0);
1259 set_gdbarch_remote_translate_xfer_address (gdbarch,
1260 avr_remote_translate_xfer_address);
1261 set_gdbarch_frame_args_skip (gdbarch, 0);
1262 set_gdbarch_frameless_function_invocation (gdbarch, frameless_look_for_prologue); /* ??? */
1263 set_gdbarch_frame_chain (gdbarch, avr_frame_chain);
1264 set_gdbarch_frame_saved_pc (gdbarch, avr_frame_saved_pc);
1265 set_gdbarch_frame_args_address (gdbarch, avr_frame_address);
1266 set_gdbarch_frame_locals_address (gdbarch, avr_frame_address);
1267 set_gdbarch_saved_pc_after_call (gdbarch, avr_saved_pc_after_call);
1268 set_gdbarch_frame_num_args (gdbarch, frame_num_args_unknown);
1270 set_gdbarch_convert_from_func_ptr_addr (gdbarch,
1271 avr_convert_from_func_ptr_addr);
1276 /* Send a query request to the avr remote target asking for values of the io
1277 registers. If args parameter is not NULL, then the user has requested info
1278 on a specific io register [This still needs implemented and is ignored for
1279 now]. The query string should be one of these forms:
1281 "Ravr.io_reg" -> reply is "NN" number of io registers
1283 "Ravr.io_reg:addr,len" where addr is first register and len is number of
1284 registers to be read. The reply should be "<NAME>,VV;" for each io register
1285 where, <NAME> is a string, and VV is the hex value of the register.
1287 All io registers are 8-bit. */
1290 avr_io_reg_read_command (char *args, int from_tty)
1296 unsigned int nreg = 0;
1300 /* fprintf_unfiltered (gdb_stderr, "DEBUG: avr_io_reg_read_command (\"%s\", %d)\n", */
1301 /* args, from_tty); */
1303 if (!current_target.to_query)
1305 fprintf_unfiltered (gdb_stderr,
1306 "ERR: info io_registers NOT supported by current target\n");
1310 /* Just get the maximum buffer size. */
1311 target_query ((int) 'R', 0, 0, &bufsiz);
1312 if (bufsiz > sizeof (buf))
1313 bufsiz = sizeof (buf);
1315 /* Find out how many io registers the target has. */
1316 strcpy (query, "avr.io_reg");
1317 target_query ((int) 'R', query, buf, &bufsiz);
1319 if (strncmp (buf, "", bufsiz) == 0)
1321 fprintf_unfiltered (gdb_stderr,
1322 "info io_registers NOT supported by target\n");
1326 if (sscanf (buf, "%x", &nreg) != 1)
1328 fprintf_unfiltered (gdb_stderr,
1329 "Error fetching number of io registers\n");
1333 reinitialize_more_filter ();
1335 printf_unfiltered ("Target has %u io registers:\n\n", nreg);
1337 /* only fetch up to 8 registers at a time to keep the buffer small */
1340 for (i = 0; i < nreg; i += step)
1342 j = step - (nreg % step); /* how many registers this round? */
1344 snprintf (query, sizeof (query) - 1, "avr.io_reg:%x,%x", i, j);
1345 target_query ((int) 'R', query, buf, &bufsiz);
1348 for (k = i; k < (i + j); k++)
1350 if (sscanf (p, "%[^,],%x;", query, &val) == 2)
1352 printf_filtered ("[%02x] %-15s : %02x\n", k, query, val);
1353 while ((*p != ';') && (*p != '\0'))
1355 p++; /* skip over ';' */
1364 _initialize_avr_tdep (void)
1366 register_gdbarch_init (bfd_arch_avr, avr_gdbarch_init);
1368 /* Add a new command to allow the user to query the avr remote target for
1369 the values of the io space registers in a saner way than just using
1372 /* FIXME: TRoth/2002-02-18: This should probably be changed to 'info avr
1373 io_registers' to signify it is not available on other platforms. */
1375 add_cmd ("io_registers", class_info, avr_io_reg_read_command,
1376 "query remote avr target for io space register values", &infolist);