1 /* Target-dependent code for Atmel AVR, for GDB.
2 Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
3 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
22 /* Contributed by Theodore A. Roth, troth@openavr.org */
24 /* Portions of this file were taken from the original gdb-4.18 patch developed
25 by Denis Chertykov, denisc@overta.ru */
29 #include "frame-unwind.h"
30 #include "frame-base.h"
31 #include "trad-frame.h"
36 #include "arch-utils.h"
38 #include "gdb_string.h"
42 (AVR micros are pure Harvard Architecture processors.)
44 The AVR family of microcontrollers have three distinctly different memory
45 spaces: flash, sram and eeprom. The flash is 16 bits wide and is used for
46 the most part to store program instructions. The sram is 8 bits wide and is
47 used for the stack and the heap. Some devices lack sram and some can have
48 an additional external sram added on as a peripheral.
50 The eeprom is 8 bits wide and is used to store data when the device is
51 powered down. Eeprom is not directly accessible, it can only be accessed
52 via io-registers using a special algorithm. Accessing eeprom via gdb's
53 remote serial protocol ('m' or 'M' packets) looks difficult to do and is
54 not included at this time.
56 [The eeprom could be read manually via ``x/b <eaddr + AVR_EMEM_START>'' or
57 written using ``set {unsigned char}<eaddr + AVR_EMEM_START>''. For this to
58 work, the remote target must be able to handle eeprom accesses and perform
59 the address translation.]
61 All three memory spaces have physical addresses beginning at 0x0. In
62 addition, the flash is addressed by gcc/binutils/gdb with respect to 8 bit
63 bytes instead of the 16 bit wide words used by the real device for the
66 In order for remote targets to work correctly, extra bits must be added to
67 addresses before they are send to the target or received from the target
68 via the remote serial protocol. The extra bits are the MSBs and are used to
69 decode which memory space the address is referring to. */
72 #define XMALLOC(TYPE) ((TYPE*) xmalloc (sizeof (TYPE)))
75 #define EXTRACT_INSN(addr) extract_unsigned_integer(addr,2)
77 /* Constants: prefixed with AVR_ to avoid name space clashes */
91 AVR_NUM_REGS = 32 + 1 /*SREG*/ + 1 /*SP*/ + 1 /*PC*/,
92 AVR_NUM_REG_BYTES = 32 + 1 /*SREG*/ + 2 /*SP*/ + 4 /*PC*/,
94 AVR_PC_REG_INDEX = 35, /* index into array of registers */
96 AVR_MAX_PROLOGUE_SIZE = 64, /* bytes */
98 /* Count of pushed registers. From r2 to r17 (inclusively), r28, r29 */
101 /* Number of the last pushed register. r17 for current avr-gcc */
102 AVR_LAST_PUSHED_REGNUM = 17,
104 AVR_ARG1_REGNUM = 24, /* Single byte argument */
105 AVR_ARGN_REGNUM = 25, /* Multi byte argments */
107 AVR_RET1_REGNUM = 24, /* Single byte return value */
108 AVR_RETN_REGNUM = 25, /* Multi byte return value */
110 /* FIXME: TRoth/2002-01-??: Can we shift all these memory masks left 8
111 bits? Do these have to match the bfd vma values?. It sure would make
112 things easier in the future if they didn't need to match.
114 Note: I chose these values so as to be consistent with bfd vma
117 TRoth/2002-04-08: There is already a conflict with very large programs
118 in the mega128. The mega128 has 128K instruction bytes (64K words),
119 thus the Most Significant Bit is 0x10000 which gets masked off my
122 The problem manifests itself when trying to set a breakpoint in a
123 function which resides in the upper half of the instruction space and
124 thus requires a 17-bit address.
126 For now, I've just removed the EEPROM mask and changed AVR_MEM_MASK
127 from 0x00ff0000 to 0x00f00000. Eeprom is not accessible from gdb yet,
128 but could be for some remote targets by just adding the correct offset
129 to the address and letting the remote target handle the low-level
130 details of actually accessing the eeprom. */
132 AVR_IMEM_START = 0x00000000, /* INSN memory */
133 AVR_SMEM_START = 0x00800000, /* SRAM memory */
135 /* No eeprom mask defined */
136 AVR_MEM_MASK = 0x00f00000, /* mask to determine memory space */
138 AVR_EMEM_START = 0x00810000, /* EEPROM memory */
139 AVR_MEM_MASK = 0x00ff0000, /* mask to determine memory space */
145 NORMAL and CALL are the typical types (the -mcall-prologues gcc option
146 causes the generation of the CALL type prologues). */
149 AVR_PROLOGUE_NONE, /* No prologue */
151 AVR_PROLOGUE_CALL, /* -mcall-prologues */
153 AVR_PROLOGUE_INTR, /* interrupt handler */
154 AVR_PROLOGUE_SIG, /* signal handler */
157 /* Any function with a frame looks like this
158 ....... <-SP POINTS HERE
159 LOCALS1 <-FP POINTS HERE
168 struct avr_unwind_cache
170 /* The previous frame's inner most stack address. Used as this
171 frame ID's stack_addr. */
173 /* The frame's base, optionally used by the high-level debug info. */
177 /* Table indicating the location of each and every register. */
178 struct trad_frame_saved_reg *saved_regs;
183 /* FIXME: TRoth: is there anything to put here? */
187 /* Lookup the name of a register given it's number. */
190 avr_register_name (int regnum)
192 static char *register_names[] = {
193 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
194 "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
195 "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
196 "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
201 if (regnum >= (sizeof (register_names) / sizeof (*register_names)))
203 return register_names[regnum];
206 /* Return the GDB type object for the "standard" data type
207 of data in register N. */
210 avr_register_type (struct gdbarch *gdbarch, int reg_nr)
212 if (reg_nr == AVR_PC_REGNUM)
213 return builtin_type_uint32;
214 if (reg_nr == AVR_SP_REGNUM)
215 return builtin_type_void_data_ptr;
217 return builtin_type_uint8;
220 /* Instruction address checks and convertions. */
223 avr_make_iaddr (CORE_ADDR x)
225 return ((x) | AVR_IMEM_START);
229 avr_iaddr_p (CORE_ADDR x)
231 return (((x) & AVR_MEM_MASK) == AVR_IMEM_START);
234 /* FIXME: TRoth: Really need to use a larger mask for instructions. Some
235 devices are already up to 128KBytes of flash space.
237 TRoth/2002-04-8: See comment above where AVR_IMEM_START is defined. */
240 avr_convert_iaddr_to_raw (CORE_ADDR x)
242 return ((x) & 0xffffffff);
245 /* SRAM address checks and convertions. */
248 avr_make_saddr (CORE_ADDR x)
250 return ((x) | AVR_SMEM_START);
254 avr_saddr_p (CORE_ADDR x)
256 return (((x) & AVR_MEM_MASK) == AVR_SMEM_START);
260 avr_convert_saddr_to_raw (CORE_ADDR x)
262 return ((x) & 0xffffffff);
265 /* EEPROM address checks and convertions. I don't know if these will ever
266 actually be used, but I've added them just the same. TRoth */
268 /* TRoth/2002-04-08: Commented out for now to allow fix for problem with large
269 programs in the mega128. */
271 /* static CORE_ADDR */
272 /* avr_make_eaddr (CORE_ADDR x) */
274 /* return ((x) | AVR_EMEM_START); */
278 /* avr_eaddr_p (CORE_ADDR x) */
280 /* return (((x) & AVR_MEM_MASK) == AVR_EMEM_START); */
283 /* static CORE_ADDR */
284 /* avr_convert_eaddr_to_raw (CORE_ADDR x) */
286 /* return ((x) & 0xffffffff); */
289 /* Convert from address to pointer and vice-versa. */
292 avr_address_to_pointer (struct type *type, void *buf, CORE_ADDR addr)
294 /* Is it a code address? */
295 if (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC
296 || TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_METHOD)
298 store_unsigned_integer (buf, TYPE_LENGTH (type),
299 avr_convert_iaddr_to_raw (addr >> 1));
303 /* Strip off any upper segment bits. */
304 store_unsigned_integer (buf, TYPE_LENGTH (type),
305 avr_convert_saddr_to_raw (addr));
310 avr_pointer_to_address (struct type *type, const void *buf)
312 CORE_ADDR addr = extract_unsigned_integer (buf, TYPE_LENGTH (type));
314 /* Is it a code address? */
315 if (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC
316 || TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_METHOD
317 || TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type)))
318 return avr_make_iaddr (addr << 1);
320 return avr_make_saddr (addr);
324 avr_read_pc (ptid_t ptid)
330 save_ptid = inferior_ptid;
331 inferior_ptid = ptid;
332 pc = (int) read_register (AVR_PC_REGNUM);
333 inferior_ptid = save_ptid;
334 retval = avr_make_iaddr (pc);
339 avr_write_pc (CORE_ADDR val, ptid_t ptid)
343 save_ptid = inferior_ptid;
344 inferior_ptid = ptid;
345 write_register (AVR_PC_REGNUM, avr_convert_iaddr_to_raw (val));
346 inferior_ptid = save_ptid;
352 return (avr_make_saddr (read_register (AVR_SP_REGNUM)));
356 avr_scan_arg_moves (int vpc, unsigned char *prologue)
360 for (; vpc < AVR_MAX_PROLOGUE_SIZE; vpc += 2)
362 insn = EXTRACT_INSN (&prologue[vpc]);
363 if ((insn & 0xff00) == 0x0100) /* movw rXX, rYY */
365 else if ((insn & 0xfc00) == 0x2c00) /* mov rXX, rYY */
374 /* Function: avr_scan_prologue
376 This function decodes an AVR function prologue to determine:
377 1) the size of the stack frame
378 2) which registers are saved on it
379 3) the offsets of saved regs
380 This information is stored in the avr_unwind_cache structure.
382 Some devices lack the sbiw instruction, so on those replace this:
388 A typical AVR function prologue with a frame pointer might look like this:
389 push rXX ; saved regs
395 sbiw r28,<LOCALS_SIZE>
396 in __tmp_reg__,__SREG__
399 out __SREG__,__tmp_reg__
402 A typical AVR function prologue without a frame pointer might look like
404 push rXX ; saved regs
407 A main function prologue looks like this:
408 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
409 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
413 A signal handler prologue looks like this:
416 in __tmp_reg__, __SREG__
419 push rXX ; save registers r18:r27, r30:r31
421 push r28 ; save frame pointer
425 sbiw r28, <LOCALS_SIZE>
429 A interrupt handler prologue looks like this:
433 in __tmp_reg__, __SREG__
436 push rXX ; save registers r18:r27, r30:r31
438 push r28 ; save frame pointer
442 sbiw r28, <LOCALS_SIZE>
448 A `-mcall-prologues' prologue looks like this (Note that the megas use a
449 jmp instead of a rjmp, thus the prologue is one word larger since jmp is a
450 32 bit insn and rjmp is a 16 bit insn):
451 ldi r26,lo8(<LOCALS_SIZE>)
452 ldi r27,hi8(<LOCALS_SIZE>)
453 ldi r30,pm_lo8(.L_foo_body)
454 ldi r31,pm_hi8(.L_foo_body)
455 rjmp __prologue_saves__+RRR
458 /* Not really part of a prologue, but still need to scan for it, is when a
459 function prologue moves values passed via registers as arguments to new
460 registers. In this case, all local variables live in registers, so there
461 may be some register saves. This is what it looks like:
465 There could be multiple movw's. If the target doesn't have a movw insn, it
466 will use two mov insns. This could be done after any of the above prologue
470 avr_scan_prologue (CORE_ADDR pc, struct avr_unwind_cache *info)
475 struct minimal_symbol *msymbol;
476 unsigned char prologue[AVR_MAX_PROLOGUE_SIZE];
479 /* FIXME: TRoth/2003-06-11: This could be made more efficient by only
480 reading in the bytes of the prologue. The problem is that the figuring
481 out where the end of the prologue is is a bit difficult. The old code
482 tried to do that, but failed quite often. */
483 read_memory (pc, prologue, AVR_MAX_PROLOGUE_SIZE);
485 /* Scanning main()'s prologue
486 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
487 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
494 unsigned char img[] = {
495 0xde, 0xbf, /* out __SP_H__,r29 */
496 0xcd, 0xbf /* out __SP_L__,r28 */
499 insn = EXTRACT_INSN (&prologue[vpc]);
500 /* ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>) */
501 if ((insn & 0xf0f0) == 0xe0c0)
503 locals = (insn & 0xf) | ((insn & 0x0f00) >> 4);
504 insn = EXTRACT_INSN (&prologue[vpc + 2]);
505 /* ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>) */
506 if ((insn & 0xf0f0) == 0xe0d0)
508 locals |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8;
509 if (memcmp (prologue + vpc + 4, img, sizeof (img)) == 0)
511 info->prologue_type = AVR_PROLOGUE_MAIN;
519 /* Scanning `-mcall-prologues' prologue
520 Classic prologue is 10 bytes, mega prologue is a 12 bytes long */
522 while (1) /* Using a while to avoid many goto's */
529 insn = EXTRACT_INSN (&prologue[vpc]);
530 /* ldi r26,<LOCALS_SIZE> */
531 if ((insn & 0xf0f0) != 0xe0a0)
533 loc_size = (insn & 0xf) | ((insn & 0x0f00) >> 4);
536 insn = EXTRACT_INSN (&prologue[vpc + 2]);
537 /* ldi r27,<LOCALS_SIZE> / 256 */
538 if ((insn & 0xf0f0) != 0xe0b0)
540 loc_size |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8;
543 insn = EXTRACT_INSN (&prologue[vpc + 4]);
544 /* ldi r30,pm_lo8(.L_foo_body) */
545 if ((insn & 0xf0f0) != 0xe0e0)
547 body_addr = (insn & 0xf) | ((insn & 0x0f00) >> 4);
550 insn = EXTRACT_INSN (&prologue[vpc + 6]);
551 /* ldi r31,pm_hi8(.L_foo_body) */
552 if ((insn & 0xf0f0) != 0xe0f0)
554 body_addr |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8;
557 msymbol = lookup_minimal_symbol ("__prologue_saves__", NULL, NULL);
561 insn = EXTRACT_INSN (&prologue[vpc + 8]);
562 /* rjmp __prologue_saves__+RRR */
563 if ((insn & 0xf000) == 0xc000)
565 /* Extract PC relative offset from RJMP */
566 i = (insn & 0xfff) | (insn & 0x800 ? (-1 ^ 0xfff) : 0);
567 /* Convert offset to byte addressable mode */
569 /* Destination address */
572 if (body_addr != (pc + 10)/2)
577 else if ((insn & 0xfe0e) == 0x940c)
579 /* Extract absolute PC address from JMP */
580 i = (((insn & 0x1) | ((insn & 0x1f0) >> 3) << 16)
581 | (EXTRACT_INSN (&prologue[vpc + 10]) & 0xffff));
582 /* Convert address to byte addressable mode */
585 if (body_addr != (pc + 12)/2)
593 /* Resolve offset (in words) from __prologue_saves__ symbol.
594 Which is a pushes count in `-mcall-prologues' mode */
595 num_pushes = AVR_MAX_PUSHES - (i - SYMBOL_VALUE_ADDRESS (msymbol)) / 2;
597 if (num_pushes > AVR_MAX_PUSHES)
599 fprintf_unfiltered (gdb_stderr, "Num pushes too large: %d\n",
608 info->saved_regs[AVR_FP_REGNUM + 1].addr = num_pushes;
610 info->saved_regs[AVR_FP_REGNUM].addr = num_pushes - 1;
613 for (from = AVR_LAST_PUSHED_REGNUM + 1 - (num_pushes - 2);
614 from <= AVR_LAST_PUSHED_REGNUM; ++from)
615 info->saved_regs [from].addr = ++i;
617 info->size = loc_size + num_pushes;
618 info->prologue_type = AVR_PROLOGUE_CALL;
620 return pc + pc_offset;
623 /* Scan for the beginning of the prologue for an interrupt or signal
624 function. Note that we have to set the prologue type here since the
625 third stage of the prologue may not be present (e.g. no saved registered
626 or changing of the SP register). */
630 unsigned char img[] = {
631 0x78, 0x94, /* sei */
632 0x1f, 0x92, /* push r1 */
633 0x0f, 0x92, /* push r0 */
634 0x0f, 0xb6, /* in r0,0x3f SREG */
635 0x0f, 0x92, /* push r0 */
636 0x11, 0x24 /* clr r1 */
638 if (memcmp (prologue, img, sizeof (img)) == 0)
640 info->prologue_type = AVR_PROLOGUE_INTR;
642 info->saved_regs[AVR_SREG_REGNUM].addr = 3;
643 info->saved_regs[0].addr = 2;
644 info->saved_regs[1].addr = 1;
647 else if (memcmp (img + 2, prologue, sizeof (img) - 2) == 0)
649 info->prologue_type = AVR_PROLOGUE_SIG;
650 vpc += sizeof (img) - 2;
651 info->saved_regs[AVR_SREG_REGNUM].addr = 3;
652 info->saved_regs[0].addr = 2;
653 info->saved_regs[1].addr = 1;
658 /* First stage of the prologue scanning.
659 Scan pushes (saved registers) */
661 for (; vpc < AVR_MAX_PROLOGUE_SIZE; vpc += 2)
663 insn = EXTRACT_INSN (&prologue[vpc]);
664 if ((insn & 0xfe0f) == 0x920f) /* push rXX */
666 /* Bits 4-9 contain a mask for registers R0-R32. */
667 int regno = (insn & 0x1f0) >> 4;
669 info->saved_regs[regno].addr = info->size;
676 if (vpc >= AVR_MAX_PROLOGUE_SIZE)
677 fprintf_unfiltered (gdb_stderr,
678 "Hit end of prologue while scanning pushes\n");
680 /* Second stage of the prologue scanning.
685 if (scan_stage == 1 && vpc < AVR_MAX_PROLOGUE_SIZE)
687 unsigned char img[] = {
688 0xcd, 0xb7, /* in r28,__SP_L__ */
689 0xde, 0xb7 /* in r29,__SP_H__ */
691 unsigned short insn1;
693 if (memcmp (prologue + vpc, img, sizeof (img)) == 0)
700 /* Third stage of the prologue scanning. (Really two stages)
702 sbiw r28,XX or subi r28,lo8(XX)
704 in __tmp_reg__,__SREG__
707 out __SREG__,__tmp_reg__
710 if (scan_stage == 2 && vpc < AVR_MAX_PROLOGUE_SIZE)
713 unsigned char img[] = {
714 0x0f, 0xb6, /* in r0,0x3f */
715 0xf8, 0x94, /* cli */
716 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
717 0x0f, 0xbe, /* out 0x3f,r0 ; SREG */
718 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
720 unsigned char img_sig[] = {
721 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
722 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
724 unsigned char img_int[] = {
725 0xf8, 0x94, /* cli */
726 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
727 0x78, 0x94, /* sei */
728 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
731 insn = EXTRACT_INSN (&prologue[vpc]);
733 if ((insn & 0xff30) == 0x9720) /* sbiw r28,XXX */
734 locals_size = (insn & 0xf) | ((insn & 0xc0) >> 2);
735 else if ((insn & 0xf0f0) == 0x50c0) /* subi r28,lo8(XX) */
737 locals_size = (insn & 0xf) | ((insn & 0xf00) >> 4);
738 insn = EXTRACT_INSN (&prologue[vpc]);
740 locals_size += ((insn & 0xf) | ((insn & 0xf00) >> 4) << 8);
745 /* Scan the last part of the prologue. May not be present for interrupt
746 or signal handler functions, which is why we set the prologue type
747 when we saw the beginning of the prologue previously. */
749 if (memcmp (prologue + vpc, img_sig, sizeof (img_sig)) == 0)
751 vpc += sizeof (img_sig);
753 else if (memcmp (prologue + vpc, img_int, sizeof (img_int)) == 0)
755 vpc += sizeof (img_int);
757 if (memcmp (prologue + vpc, img, sizeof (img)) == 0)
759 info->prologue_type = AVR_PROLOGUE_NORMAL;
763 info->size += locals_size;
765 return pc + avr_scan_arg_moves (vpc, prologue);
768 /* If we got this far, we could not scan the prologue, so just return the pc
769 of the frame plus an adjustment for argument move insns. */
771 return pc + avr_scan_arg_moves (vpc, prologue);;
774 /* Returns the return address for a dummy. */
777 avr_call_dummy_address (void)
779 return entry_point_address ();
783 avr_skip_prologue (CORE_ADDR pc)
785 CORE_ADDR func_addr, func_end;
786 CORE_ADDR prologue_end = pc;
788 /* See what the symbol table says */
790 if (find_pc_partial_function (pc, NULL, &func_addr, &func_end))
792 struct symtab_and_line sal;
793 struct avr_unwind_cache info = {0};
794 struct trad_frame_saved_reg saved_regs[AVR_NUM_REGS];
796 info.saved_regs = saved_regs;
798 /* Need to run the prologue scanner to figure out if the function has a
799 prologue and possibly skip over moving arguments passed via registers
800 to other registers. */
802 prologue_end = avr_scan_prologue (pc, &info);
804 if (info.prologue_type != AVR_PROLOGUE_NONE)
806 sal = find_pc_line (func_addr, 0);
808 if (sal.line != 0 && sal.end < func_end)
813 /* Either we didn't find the start of this function (nothing we can do),
814 or there's no line info, or the line after the prologue is after
815 the end of the function (there probably isn't a prologue). */
821 avr_frame_address (struct frame_info *fi)
823 return avr_make_saddr (get_frame_base (fi));
826 /* Not all avr devices support the BREAK insn. Those that don't should treat
827 it as a NOP. Thus, it should be ok. Since the avr is currently a remote
828 only target, this shouldn't be a problem (I hope). TRoth/2003-05-14 */
830 static const unsigned char *
831 avr_breakpoint_from_pc (CORE_ADDR * pcptr, int *lenptr)
833 static unsigned char avr_break_insn [] = { 0x98, 0x95 };
834 *lenptr = sizeof (avr_break_insn);
835 return avr_break_insn;
838 /* Given a return value in `regbuf' with a type `valtype',
839 extract and copy its value into `valbuf'.
841 Return values are always passed via registers r25:r24:... */
844 avr_extract_return_value (struct type *type, struct regcache *regcache,
850 if (TYPE_LENGTH (type) == 1)
852 regcache_cooked_read_unsigned (regcache, 24, &c);
853 store_unsigned_integer (valbuf, 1, c);
858 /* The MSB of the return value is always in r25, calculate which
859 register holds the LSB. */
860 int lsb_reg = 25 - TYPE_LENGTH (type) + 1;
862 for (i=0; i< TYPE_LENGTH (type); i++)
864 regcache_cooked_read (regcache, lsb_reg + i,
865 (bfd_byte *) valbuf + i);
871 avr_saved_regs_unwinder (struct frame_info *next_frame,
872 struct trad_frame_saved_reg *this_saved_regs,
873 int regnum, int *optimizedp,
874 enum lval_type *lvalp, CORE_ADDR *addrp,
875 int *realnump, void *bufferp)
877 if (this_saved_regs[regnum].addr != 0)
880 *lvalp = lval_memory;
881 *addrp = this_saved_regs[regnum].addr;
885 /* Read the value in from memory. */
887 if (regnum == AVR_PC_REGNUM)
889 /* Reading the return PC from the PC register is slightly
890 abnormal. register_size(AVR_PC_REGNUM) says it is 4 bytes,
891 but in reality, only two bytes (3 in upcoming mega256) are
894 Also, note that the value on the stack is an addr to a word
895 not a byte, so we will need to multiply it by two at some
898 And to confuse matters even more, the return address stored
899 on the stack is in big endian byte order, even though most
900 everything else about the avr is little endian. Ick! */
902 /* FIXME: number of bytes read here will need updated for the
903 mega256 when it is available. */
907 unsigned char buf[2];
909 read_memory (this_saved_regs[regnum].addr, buf, 2);
911 /* Convert the PC read from memory as a big-endian to
912 little-endian order. */
917 pc = (extract_unsigned_integer (buf, 2) * 2);
918 store_unsigned_integer (bufferp,
919 register_size (current_gdbarch, regnum),
924 read_memory (this_saved_regs[regnum].addr, bufferp,
925 register_size (current_gdbarch, regnum));
932 /* No luck, assume this and the next frame have the same register
933 value. If a value is needed, pass the request on down the chain;
934 otherwise just return an indication that the value is in the same
935 register as the next frame. */
936 frame_register_unwind (next_frame, regnum, optimizedp, lvalp, addrp,
940 /* Put here the code to store, into fi->saved_regs, the addresses of
941 the saved registers of frame described by FRAME_INFO. This
942 includes special registers such as pc and fp saved in special ways
943 in the stack frame. sp is even more special: the address we return
944 for it IS the sp for the next frame. */
946 struct avr_unwind_cache *
947 avr_frame_unwind_cache (struct frame_info *next_frame,
948 void **this_prologue_cache)
953 struct avr_unwind_cache *info;
956 if ((*this_prologue_cache))
957 return (*this_prologue_cache);
959 info = FRAME_OBSTACK_ZALLOC (struct avr_unwind_cache);
960 (*this_prologue_cache) = info;
961 info->saved_regs = trad_frame_alloc_saved_regs (next_frame);
964 info->prologue_type = AVR_PROLOGUE_NONE;
966 pc = frame_func_unwind (next_frame);
968 if ((pc > 0) && (pc < frame_pc_unwind (next_frame)))
969 avr_scan_prologue (pc, info);
971 if (info->prologue_type != AVR_PROLOGUE_NONE)
973 ULONGEST high_base; /* High byte of FP */
975 /* The SP was moved to the FP. This indicates that a new frame
976 was created. Get THIS frame's FP value by unwinding it from
978 frame_unwind_unsigned_register (next_frame, AVR_FP_REGNUM, &this_base);
979 frame_unwind_unsigned_register (next_frame, AVR_FP_REGNUM+1, &high_base);
980 this_base += (high_base << 8);
982 /* The FP points at the last saved register. Adjust the FP back
983 to before the first saved register giving the SP. */
984 prev_sp = this_base + info->size;
988 /* Assume that the FP is this frame's SP but with that pushed
989 stack space added back. */
990 frame_unwind_unsigned_register (next_frame, AVR_SP_REGNUM, &this_base);
991 prev_sp = this_base + info->size;
994 /* Add 1 here to adjust for the post-decrement nature of the push
996 info->prev_sp = avr_make_saddr (prev_sp+1);
998 info->base = avr_make_saddr (this_base);
1000 /* Adjust all the saved registers so that they contain addresses and not
1001 offsets. We need to add one to the addresses since push ops are post
1002 decrement on the avr. */
1003 for (i = 0; i < NUM_REGS - 1; i++)
1004 if (info->saved_regs[i].addr)
1006 info->saved_regs[i].addr = (info->prev_sp - info->saved_regs[i].addr);
1009 /* Except for the main and startup code, the return PC is always saved on
1010 the stack and is at the base of the frame. */
1012 if (info->prologue_type != AVR_PROLOGUE_MAIN)
1014 info->saved_regs[AVR_PC_REGNUM].addr = info->prev_sp;
1021 avr_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
1025 frame_unwind_unsigned_register (next_frame, AVR_PC_REGNUM, &pc);
1027 return avr_make_iaddr (pc);
1030 /* Given a GDB frame, determine the address of the calling function's
1031 frame. This will be used to create a new GDB frame struct. */
1034 avr_frame_this_id (struct frame_info *next_frame,
1035 void **this_prologue_cache,
1036 struct frame_id *this_id)
1038 struct avr_unwind_cache *info
1039 = avr_frame_unwind_cache (next_frame, this_prologue_cache);
1044 /* The FUNC is easy. */
1045 func = frame_func_unwind (next_frame);
1047 /* This is meant to halt the backtrace at "_start". Make sure we
1048 don't halt it at a generic dummy frame. */
1049 if (inside_entry_file (func))
1052 /* Hopefully the prologue analysis either correctly determined the
1053 frame's base (which is the SP from the previous frame), or set
1054 that base to "NULL". */
1055 base = info->prev_sp;
1059 id = frame_id_build (base, func);
1061 /* Check that we're not going round in circles with the same frame
1062 ID (but avoid applying the test to sentinel frames which do go
1063 round in circles). Can't use frame_id_eq() as that doesn't yet
1064 compare the frame's PC value. */
1065 if (frame_relative_level (next_frame) >= 0
1066 && get_frame_type (next_frame) != DUMMY_FRAME
1067 && frame_id_eq (get_frame_id (next_frame), id))
1074 avr_frame_prev_register (struct frame_info *next_frame,
1075 void **this_prologue_cache,
1076 int regnum, int *optimizedp,
1077 enum lval_type *lvalp, CORE_ADDR *addrp,
1078 int *realnump, void *bufferp)
1080 struct avr_unwind_cache *info
1081 = avr_frame_unwind_cache (next_frame, this_prologue_cache);
1083 avr_saved_regs_unwinder (next_frame, info->saved_regs, regnum, optimizedp,
1084 lvalp, addrp, realnump, bufferp);
1087 static const struct frame_unwind avr_frame_unwind = {
1090 avr_frame_prev_register
1093 const struct frame_unwind *
1094 avr_frame_p (CORE_ADDR pc)
1096 return &avr_frame_unwind;
1100 avr_frame_base_address (struct frame_info *next_frame, void **this_cache)
1102 struct avr_unwind_cache *info
1103 = avr_frame_unwind_cache (next_frame, this_cache);
1108 static const struct frame_base avr_frame_base = {
1110 avr_frame_base_address,
1111 avr_frame_base_address,
1112 avr_frame_base_address
1115 /* Assuming NEXT_FRAME->prev is a dummy, return the frame ID of that
1116 dummy frame. The frame ID's base needs to match the TOS value
1117 saved by save_dummy_frame_tos(), and the PC match the dummy frame's
1120 static struct frame_id
1121 avr_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame)
1125 frame_unwind_unsigned_register (next_frame, AVR_SP_REGNUM, &base);
1126 return frame_id_build (avr_make_saddr (base), frame_pc_unwind (next_frame));
1129 /* When arguments must be pushed onto the stack, they go on in reverse
1130 order. The below implements a FILO (stack) to do this. */
1135 struct stack_item *prev;
1139 static struct stack_item *push_stack_item (struct stack_item *prev,
1140 void *contents, int len);
1141 static struct stack_item *
1142 push_stack_item (struct stack_item *prev, void *contents, int len)
1144 struct stack_item *si;
1145 si = xmalloc (sizeof (struct stack_item));
1146 si->data = xmalloc (len);
1149 memcpy (si->data, contents, len);
1153 static struct stack_item *pop_stack_item (struct stack_item *si);
1154 static struct stack_item *
1155 pop_stack_item (struct stack_item *si)
1157 struct stack_item *dead = si;
1164 /* Setup the function arguments for calling a function in the inferior.
1166 On the AVR architecture, there are 18 registers (R25 to R8) which are
1167 dedicated for passing function arguments. Up to the first 18 arguments
1168 (depending on size) may go into these registers. The rest go on the stack.
1170 All arguments are aligned to start in even-numbered registers (odd-sized
1171 arguments, including char, have one free register above them). For example,
1172 an int in arg1 and a char in arg2 would be passed as such:
1177 Arguments that are larger than 2 bytes will be split between two or more
1178 registers as available, but will NOT be split between a register and the
1179 stack. Arguments that go onto the stack are pushed last arg first (this is
1180 similar to the d10v). */
1182 /* NOTE: TRoth/2003-06-17: The rest of this comment is old looks to be
1185 An exceptional case exists for struct arguments (and possibly other
1186 aggregates such as arrays) -- if the size is larger than WORDSIZE bytes but
1187 not a multiple of WORDSIZE bytes. In this case the argument is never split
1188 between the registers and the stack, but instead is copied in its entirety
1189 onto the stack, AND also copied into as many registers as there is room
1190 for. In other words, space in registers permitting, two copies of the same
1191 argument are passed in. As far as I can tell, only the one on the stack is
1192 used, although that may be a function of the level of compiler
1193 optimization. I suspect this is a compiler bug. Arguments of these odd
1194 sizes are left-justified within the word (as opposed to arguments smaller
1195 than WORDSIZE bytes, which are right-justified).
1197 If the function is to return an aggregate type such as a struct, the caller
1198 must allocate space into which the callee will copy the return value. In
1199 this case, a pointer to the return value location is passed into the callee
1200 in register R0, which displaces one of the other arguments passed in via
1201 registers R0 to R2. */
1204 avr_push_dummy_call (struct gdbarch *gdbarch, CORE_ADDR func_addr,
1205 struct regcache *regcache, CORE_ADDR bp_addr,
1206 int nargs, struct value **args, CORE_ADDR sp,
1207 int struct_return, CORE_ADDR struct_addr)
1210 unsigned char buf[2];
1211 CORE_ADDR return_pc = avr_convert_iaddr_to_raw (bp_addr);
1212 int regnum = AVR_ARGN_REGNUM;
1213 struct stack_item *si = NULL;
1216 /* FIXME: TRoth/2003-06-18: Not sure what to do when returning a struct. */
1219 fprintf_unfiltered (gdb_stderr, "struct_return: 0x%lx\n", struct_addr);
1220 write_register (argreg--, struct_addr & 0xff);
1221 write_register (argreg--, (struct_addr >>8) & 0xff);
1225 for (i = 0; i < nargs; i++)
1229 struct value *arg = args[i];
1230 struct type *type = check_typedef (VALUE_TYPE (arg));
1231 char *contents = VALUE_CONTENTS (arg);
1232 int len = TYPE_LENGTH (type);
1234 /* Calculate the potential last register needed. */
1235 last_regnum = regnum - (len + (len & 1));
1237 /* If there are registers available, use them. Once we start putting
1238 stuff on the stack, all subsequent args go on stack. */
1239 if ((si == NULL) && (last_regnum >= 8))
1243 /* Skip a register for odd length args. */
1247 val = extract_unsigned_integer (contents, len);
1248 for (j=0; j<len; j++)
1250 regcache_cooked_write_unsigned (regcache, regnum--,
1251 val >> (8*(len-j-1)));
1254 /* No registers available, push the args onto the stack. */
1257 /* From here on, we don't care about regnum. */
1258 si = push_stack_item (si, contents, len);
1262 /* Push args onto the stack. */
1266 /* Add 1 to sp here to account for post decr nature of pushes. */
1267 write_memory (sp+1, si->data, si->len);
1268 si = pop_stack_item (si);
1271 /* Set the return address. For the avr, the return address is the BP_ADDR.
1272 Need to push the return address onto the stack noting that it needs to be
1273 in big-endian order on the stack. */
1274 buf[0] = (return_pc >> 8) & 0xff;
1275 buf[1] = return_pc & 0xff;
1278 write_memory (sp+1, buf, 2); /* Add one since pushes are post decr ops. */
1280 /* Finally, update the SP register. */
1281 regcache_cooked_write_unsigned (regcache, AVR_SP_REGNUM,
1282 avr_convert_saddr_to_raw (sp));
1287 /* Initialize the gdbarch structure for the AVR's. */
1289 static struct gdbarch *
1290 avr_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
1292 struct gdbarch *gdbarch;
1293 struct gdbarch_tdep *tdep;
1295 /* Find a candidate among the list of pre-declared architectures. */
1296 arches = gdbarch_list_lookup_by_info (arches, &info);
1298 return arches->gdbarch;
1300 /* None found, create a new architecture from the information provided. */
1301 tdep = XMALLOC (struct gdbarch_tdep);
1302 gdbarch = gdbarch_alloc (&info, tdep);
1304 /* If we ever need to differentiate the device types, do it here. */
1305 switch (info.bfd_arch_info->mach)
1315 set_gdbarch_short_bit (gdbarch, 2 * TARGET_CHAR_BIT);
1316 set_gdbarch_int_bit (gdbarch, 2 * TARGET_CHAR_BIT);
1317 set_gdbarch_long_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1318 set_gdbarch_long_long_bit (gdbarch, 8 * TARGET_CHAR_BIT);
1319 set_gdbarch_ptr_bit (gdbarch, 2 * TARGET_CHAR_BIT);
1320 set_gdbarch_addr_bit (gdbarch, 32);
1321 set_gdbarch_bfd_vma_bit (gdbarch, 32); /* FIXME: TRoth/2002-02-18: Is this needed? */
1323 set_gdbarch_float_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1324 set_gdbarch_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1325 set_gdbarch_long_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1327 set_gdbarch_float_format (gdbarch, &floatformat_ieee_single_little);
1328 set_gdbarch_double_format (gdbarch, &floatformat_ieee_single_little);
1329 set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_single_little);
1331 set_gdbarch_read_pc (gdbarch, avr_read_pc);
1332 set_gdbarch_write_pc (gdbarch, avr_write_pc);
1333 set_gdbarch_read_sp (gdbarch, avr_read_sp);
1335 set_gdbarch_num_regs (gdbarch, AVR_NUM_REGS);
1337 set_gdbarch_sp_regnum (gdbarch, AVR_SP_REGNUM);
1338 set_gdbarch_pc_regnum (gdbarch, AVR_PC_REGNUM);
1340 set_gdbarch_register_name (gdbarch, avr_register_name);
1341 set_gdbarch_register_type (gdbarch, avr_register_type);
1343 set_gdbarch_extract_return_value (gdbarch, avr_extract_return_value);
1344 set_gdbarch_print_insn (gdbarch, print_insn_avr);
1346 set_gdbarch_call_dummy_address (gdbarch, avr_call_dummy_address);
1347 set_gdbarch_push_dummy_call (gdbarch, avr_push_dummy_call);
1349 set_gdbarch_address_to_pointer (gdbarch, avr_address_to_pointer);
1350 set_gdbarch_pointer_to_address (gdbarch, avr_pointer_to_address);
1352 set_gdbarch_use_struct_convention (gdbarch, generic_use_struct_convention);
1354 set_gdbarch_skip_prologue (gdbarch, avr_skip_prologue);
1355 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
1357 set_gdbarch_decr_pc_after_break (gdbarch, 0);
1358 set_gdbarch_breakpoint_from_pc (gdbarch, avr_breakpoint_from_pc);
1360 set_gdbarch_function_start_offset (gdbarch, 0);
1362 set_gdbarch_frame_args_skip (gdbarch, 0);
1363 set_gdbarch_frameless_function_invocation (gdbarch,
1364 frameless_look_for_prologue);
1365 set_gdbarch_frame_args_address (gdbarch, avr_frame_address);
1366 set_gdbarch_frame_locals_address (gdbarch, avr_frame_address);
1368 frame_unwind_append_predicate (gdbarch, avr_frame_p);
1369 frame_base_set_default (gdbarch, &avr_frame_base);
1371 set_gdbarch_unwind_dummy_id (gdbarch, avr_unwind_dummy_id);
1373 set_gdbarch_unwind_pc (gdbarch, avr_unwind_pc);
1378 /* Send a query request to the avr remote target asking for values of the io
1379 registers. If args parameter is not NULL, then the user has requested info
1380 on a specific io register [This still needs implemented and is ignored for
1381 now]. The query string should be one of these forms:
1383 "Ravr.io_reg" -> reply is "NN" number of io registers
1385 "Ravr.io_reg:addr,len" where addr is first register and len is number of
1386 registers to be read. The reply should be "<NAME>,VV;" for each io register
1387 where, <NAME> is a string, and VV is the hex value of the register.
1389 All io registers are 8-bit. */
1392 avr_io_reg_read_command (char *args, int from_tty)
1398 unsigned int nreg = 0;
1402 if (!current_target.to_query)
1404 fprintf_unfiltered (gdb_stderr,
1405 "ERR: info io_registers NOT supported by current "
1410 /* Just get the maximum buffer size. */
1411 target_query ((int) 'R', 0, 0, &bufsiz);
1412 if (bufsiz > sizeof (buf))
1413 bufsiz = sizeof (buf);
1415 /* Find out how many io registers the target has. */
1416 strcpy (query, "avr.io_reg");
1417 target_query ((int) 'R', query, buf, &bufsiz);
1419 if (strncmp (buf, "", bufsiz) == 0)
1421 fprintf_unfiltered (gdb_stderr,
1422 "info io_registers NOT supported by target\n");
1426 if (sscanf (buf, "%x", &nreg) != 1)
1428 fprintf_unfiltered (gdb_stderr,
1429 "Error fetching number of io registers\n");
1433 reinitialize_more_filter ();
1435 printf_unfiltered ("Target has %u io registers:\n\n", nreg);
1437 /* only fetch up to 8 registers at a time to keep the buffer small */
1440 for (i = 0; i < nreg; i += step)
1442 /* how many registers this round? */
1445 j = nreg - i; /* last block is less than 8 registers */
1447 snprintf (query, sizeof (query) - 1, "avr.io_reg:%x,%x", i, j);
1448 target_query ((int) 'R', query, buf, &bufsiz);
1451 for (k = i; k < (i + j); k++)
1453 if (sscanf (p, "%[^,],%x;", query, &val) == 2)
1455 printf_filtered ("[%02x] %-15s : %02x\n", k, query, val);
1456 while ((*p != ';') && (*p != '\0'))
1458 p++; /* skip over ';' */
1466 extern initialize_file_ftype _initialize_avr_tdep; /* -Wmissing-prototypes */
1469 _initialize_avr_tdep (void)
1471 register_gdbarch_init (bfd_arch_avr, avr_gdbarch_init);
1473 /* Add a new command to allow the user to query the avr remote target for
1474 the values of the io space registers in a saner way than just using
1477 /* FIXME: TRoth/2002-02-18: This should probably be changed to 'info avr
1478 io_registers' to signify it is not available on other platforms. */
1480 add_cmd ("io_registers", class_info, avr_io_reg_read_command,
1481 "query remote avr target for io space register values", &infolist);