1 /* Target-dependent code for Atmel AVR, for GDB.
2 Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
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"
43 (AVR micros are pure Harvard Architecture processors.)
45 The AVR family of microcontrollers have three distinctly different memory
46 spaces: flash, sram and eeprom. The flash is 16 bits wide and is used for
47 the most part to store program instructions. The sram is 8 bits wide and is
48 used for the stack and the heap. Some devices lack sram and some can have
49 an additional external sram added on as a peripheral.
51 The eeprom is 8 bits wide and is used to store data when the device is
52 powered down. Eeprom is not directly accessible, it can only be accessed
53 via io-registers using a special algorithm. Accessing eeprom via gdb's
54 remote serial protocol ('m' or 'M' packets) looks difficult to do and is
55 not included at this time.
57 [The eeprom could be read manually via ``x/b <eaddr + AVR_EMEM_START>'' or
58 written using ``set {unsigned char}<eaddr + AVR_EMEM_START>''. For this to
59 work, the remote target must be able to handle eeprom accesses and perform
60 the address translation.]
62 All three memory spaces have physical addresses beginning at 0x0. In
63 addition, the flash is addressed by gcc/binutils/gdb with respect to 8 bit
64 bytes instead of the 16 bit wide words used by the real device for the
67 In order for remote targets to work correctly, extra bits must be added to
68 addresses before they are send to the target or received from the target
69 via the remote serial protocol. The extra bits are the MSBs and are used to
70 decode which memory space the address is referring to. */
73 #define XMALLOC(TYPE) ((TYPE*) xmalloc (sizeof (TYPE)))
76 #define EXTRACT_INSN(addr) extract_unsigned_integer(addr,2)
78 /* Constants: prefixed with AVR_ to avoid name space clashes */
92 AVR_NUM_REGS = 32 + 1 /*SREG*/ + 1 /*SP*/ + 1 /*PC*/,
93 AVR_NUM_REG_BYTES = 32 + 1 /*SREG*/ + 2 /*SP*/ + 4 /*PC*/,
95 AVR_PC_REG_INDEX = 35, /* index into array of registers */
97 AVR_MAX_PROLOGUE_SIZE = 64, /* bytes */
99 /* Count of pushed registers. From r2 to r17 (inclusively), r28, r29 */
102 /* Number of the last pushed register. r17 for current avr-gcc */
103 AVR_LAST_PUSHED_REGNUM = 17,
105 AVR_ARG1_REGNUM = 24, /* Single byte argument */
106 AVR_ARGN_REGNUM = 25, /* Multi byte argments */
108 AVR_RET1_REGNUM = 24, /* Single byte return value */
109 AVR_RETN_REGNUM = 25, /* Multi byte return value */
111 /* FIXME: TRoth/2002-01-??: Can we shift all these memory masks left 8
112 bits? Do these have to match the bfd vma values?. It sure would make
113 things easier in the future if they didn't need to match.
115 Note: I chose these values so as to be consistent with bfd vma
118 TRoth/2002-04-08: There is already a conflict with very large programs
119 in the mega128. The mega128 has 128K instruction bytes (64K words),
120 thus the Most Significant Bit is 0x10000 which gets masked off my
123 The problem manifests itself when trying to set a breakpoint in a
124 function which resides in the upper half of the instruction space and
125 thus requires a 17-bit address.
127 For now, I've just removed the EEPROM mask and changed AVR_MEM_MASK
128 from 0x00ff0000 to 0x00f00000. Eeprom is not accessible from gdb yet,
129 but could be for some remote targets by just adding the correct offset
130 to the address and letting the remote target handle the low-level
131 details of actually accessing the eeprom. */
133 AVR_IMEM_START = 0x00000000, /* INSN memory */
134 AVR_SMEM_START = 0x00800000, /* SRAM memory */
136 /* No eeprom mask defined */
137 AVR_MEM_MASK = 0x00f00000, /* mask to determine memory space */
139 AVR_EMEM_START = 0x00810000, /* EEPROM memory */
140 AVR_MEM_MASK = 0x00ff0000, /* mask to determine memory space */
146 NORMAL and CALL are the typical types (the -mcall-prologues gcc option
147 causes the generation of the CALL type prologues). */
150 AVR_PROLOGUE_NONE, /* No prologue */
152 AVR_PROLOGUE_CALL, /* -mcall-prologues */
154 AVR_PROLOGUE_INTR, /* interrupt handler */
155 AVR_PROLOGUE_SIG, /* signal handler */
158 /* Any function with a frame looks like this
159 ....... <-SP POINTS HERE
160 LOCALS1 <-FP POINTS HERE
169 struct avr_unwind_cache
171 /* The previous frame's inner most stack address. Used as this
172 frame ID's stack_addr. */
174 /* The frame's base, optionally used by the high-level debug info. */
178 /* Table indicating the location of each and every register. */
179 struct trad_frame_saved_reg *saved_regs;
184 /* FIXME: TRoth: is there anything to put here? */
188 /* Lookup the name of a register given it's number. */
191 avr_register_name (int regnum)
193 static char *register_names[] = {
194 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
195 "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
196 "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
197 "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
202 if (regnum >= (sizeof (register_names) / sizeof (*register_names)))
204 return register_names[regnum];
207 /* Return the GDB type object for the "standard" data type
208 of data in register N. */
211 avr_register_type (struct gdbarch *gdbarch, int reg_nr)
213 if (reg_nr == AVR_PC_REGNUM)
214 return builtin_type_uint32;
215 if (reg_nr == AVR_SP_REGNUM)
216 return builtin_type_void_data_ptr;
218 return builtin_type_uint8;
221 /* Instruction address checks and convertions. */
224 avr_make_iaddr (CORE_ADDR x)
226 return ((x) | AVR_IMEM_START);
229 /* FIXME: TRoth: Really need to use a larger mask for instructions. Some
230 devices are already up to 128KBytes of flash space.
232 TRoth/2002-04-8: See comment above where AVR_IMEM_START is defined. */
235 avr_convert_iaddr_to_raw (CORE_ADDR x)
237 return ((x) & 0xffffffff);
240 /* SRAM address checks and convertions. */
243 avr_make_saddr (CORE_ADDR x)
245 return ((x) | AVR_SMEM_START);
249 avr_convert_saddr_to_raw (CORE_ADDR x)
251 return ((x) & 0xffffffff);
254 /* EEPROM address checks and convertions. I don't know if these will ever
255 actually be used, but I've added them just the same. TRoth */
257 /* TRoth/2002-04-08: Commented out for now to allow fix for problem with large
258 programs in the mega128. */
260 /* static CORE_ADDR */
261 /* avr_make_eaddr (CORE_ADDR x) */
263 /* return ((x) | AVR_EMEM_START); */
267 /* avr_eaddr_p (CORE_ADDR x) */
269 /* return (((x) & AVR_MEM_MASK) == AVR_EMEM_START); */
272 /* static CORE_ADDR */
273 /* avr_convert_eaddr_to_raw (CORE_ADDR x) */
275 /* return ((x) & 0xffffffff); */
278 /* Convert from address to pointer and vice-versa. */
281 avr_address_to_pointer (struct type *type, void *buf, CORE_ADDR addr)
283 /* Is it a code address? */
284 if (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC
285 || TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_METHOD)
287 store_unsigned_integer (buf, TYPE_LENGTH (type),
288 avr_convert_iaddr_to_raw (addr >> 1));
292 /* Strip off any upper segment bits. */
293 store_unsigned_integer (buf, TYPE_LENGTH (type),
294 avr_convert_saddr_to_raw (addr));
299 avr_pointer_to_address (struct type *type, const void *buf)
301 CORE_ADDR addr = extract_unsigned_integer (buf, TYPE_LENGTH (type));
303 /* Is it a code address? */
304 if (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC
305 || TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_METHOD
306 || TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type)))
307 return avr_make_iaddr (addr << 1);
309 return avr_make_saddr (addr);
313 avr_read_pc (ptid_t ptid)
319 save_ptid = inferior_ptid;
320 inferior_ptid = ptid;
321 regcache_cooked_read_unsigned (current_regcache, AVR_PC_REGNUM, &pc);
322 inferior_ptid = save_ptid;
323 retval = avr_make_iaddr (pc);
328 avr_write_pc (CORE_ADDR val, ptid_t ptid)
332 save_ptid = inferior_ptid;
333 inferior_ptid = ptid;
334 write_register (AVR_PC_REGNUM, avr_convert_iaddr_to_raw (val));
335 inferior_ptid = save_ptid;
343 regcache_cooked_read_unsigned (current_regcache, AVR_SP_REGNUM, &sp);
344 return (avr_make_saddr (sp));
348 avr_scan_arg_moves (int vpc, unsigned char *prologue)
352 for (; vpc < AVR_MAX_PROLOGUE_SIZE; vpc += 2)
354 insn = EXTRACT_INSN (&prologue[vpc]);
355 if ((insn & 0xff00) == 0x0100) /* movw rXX, rYY */
357 else if ((insn & 0xfc00) == 0x2c00) /* mov rXX, rYY */
366 /* Function: avr_scan_prologue
368 This function decodes an AVR function prologue to determine:
369 1) the size of the stack frame
370 2) which registers are saved on it
371 3) the offsets of saved regs
372 This information is stored in the avr_unwind_cache structure.
374 Some devices lack the sbiw instruction, so on those replace this:
380 A typical AVR function prologue with a frame pointer might look like this:
381 push rXX ; saved regs
387 sbiw r28,<LOCALS_SIZE>
388 in __tmp_reg__,__SREG__
391 out __SREG__,__tmp_reg__
394 A typical AVR function prologue without a frame pointer might look like
396 push rXX ; saved regs
399 A main function prologue looks like this:
400 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
401 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
405 A signal handler prologue looks like this:
408 in __tmp_reg__, __SREG__
411 push rXX ; save registers r18:r27, r30:r31
413 push r28 ; save frame pointer
417 sbiw r28, <LOCALS_SIZE>
421 A interrupt handler prologue looks like this:
425 in __tmp_reg__, __SREG__
428 push rXX ; save registers r18:r27, r30:r31
430 push r28 ; save frame pointer
434 sbiw r28, <LOCALS_SIZE>
440 A `-mcall-prologues' prologue looks like this (Note that the megas use a
441 jmp instead of a rjmp, thus the prologue is one word larger since jmp is a
442 32 bit insn and rjmp is a 16 bit insn):
443 ldi r26,lo8(<LOCALS_SIZE>)
444 ldi r27,hi8(<LOCALS_SIZE>)
445 ldi r30,pm_lo8(.L_foo_body)
446 ldi r31,pm_hi8(.L_foo_body)
447 rjmp __prologue_saves__+RRR
450 /* Not really part of a prologue, but still need to scan for it, is when a
451 function prologue moves values passed via registers as arguments to new
452 registers. In this case, all local variables live in registers, so there
453 may be some register saves. This is what it looks like:
457 There could be multiple movw's. If the target doesn't have a movw insn, it
458 will use two mov insns. This could be done after any of the above prologue
462 avr_scan_prologue (CORE_ADDR pc, struct avr_unwind_cache *info)
467 struct minimal_symbol *msymbol;
468 unsigned char prologue[AVR_MAX_PROLOGUE_SIZE];
471 /* FIXME: TRoth/2003-06-11: This could be made more efficient by only
472 reading in the bytes of the prologue. The problem is that the figuring
473 out where the end of the prologue is is a bit difficult. The old code
474 tried to do that, but failed quite often. */
475 read_memory (pc, prologue, AVR_MAX_PROLOGUE_SIZE);
477 /* Scanning main()'s prologue
478 ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>)
479 ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>)
486 unsigned char img[] = {
487 0xde, 0xbf, /* out __SP_H__,r29 */
488 0xcd, 0xbf /* out __SP_L__,r28 */
491 insn = EXTRACT_INSN (&prologue[vpc]);
492 /* ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>) */
493 if ((insn & 0xf0f0) == 0xe0c0)
495 locals = (insn & 0xf) | ((insn & 0x0f00) >> 4);
496 insn = EXTRACT_INSN (&prologue[vpc + 2]);
497 /* ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>) */
498 if ((insn & 0xf0f0) == 0xe0d0)
500 locals |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8;
501 if (memcmp (prologue + vpc + 4, img, sizeof (img)) == 0)
503 info->prologue_type = AVR_PROLOGUE_MAIN;
511 /* Scanning `-mcall-prologues' prologue
512 Classic prologue is 10 bytes, mega prologue is a 12 bytes long */
514 while (1) /* Using a while to avoid many goto's */
521 insn = EXTRACT_INSN (&prologue[vpc]);
522 /* ldi r26,<LOCALS_SIZE> */
523 if ((insn & 0xf0f0) != 0xe0a0)
525 loc_size = (insn & 0xf) | ((insn & 0x0f00) >> 4);
528 insn = EXTRACT_INSN (&prologue[vpc + 2]);
529 /* ldi r27,<LOCALS_SIZE> / 256 */
530 if ((insn & 0xf0f0) != 0xe0b0)
532 loc_size |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8;
535 insn = EXTRACT_INSN (&prologue[vpc + 4]);
536 /* ldi r30,pm_lo8(.L_foo_body) */
537 if ((insn & 0xf0f0) != 0xe0e0)
539 body_addr = (insn & 0xf) | ((insn & 0x0f00) >> 4);
542 insn = EXTRACT_INSN (&prologue[vpc + 6]);
543 /* ldi r31,pm_hi8(.L_foo_body) */
544 if ((insn & 0xf0f0) != 0xe0f0)
546 body_addr |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8;
549 msymbol = lookup_minimal_symbol ("__prologue_saves__", NULL, NULL);
553 insn = EXTRACT_INSN (&prologue[vpc + 8]);
554 /* rjmp __prologue_saves__+RRR */
555 if ((insn & 0xf000) == 0xc000)
557 /* Extract PC relative offset from RJMP */
558 i = (insn & 0xfff) | (insn & 0x800 ? (-1 ^ 0xfff) : 0);
559 /* Convert offset to byte addressable mode */
561 /* Destination address */
564 if (body_addr != (pc + 10)/2)
569 else if ((insn & 0xfe0e) == 0x940c)
571 /* Extract absolute PC address from JMP */
572 i = (((insn & 0x1) | ((insn & 0x1f0) >> 3) << 16)
573 | (EXTRACT_INSN (&prologue[vpc + 10]) & 0xffff));
574 /* Convert address to byte addressable mode */
577 if (body_addr != (pc + 12)/2)
585 /* Resolve offset (in words) from __prologue_saves__ symbol.
586 Which is a pushes count in `-mcall-prologues' mode */
587 num_pushes = AVR_MAX_PUSHES - (i - SYMBOL_VALUE_ADDRESS (msymbol)) / 2;
589 if (num_pushes > AVR_MAX_PUSHES)
591 fprintf_unfiltered (gdb_stderr, "Num pushes too large: %d\n",
600 info->saved_regs[AVR_FP_REGNUM + 1].addr = num_pushes;
602 info->saved_regs[AVR_FP_REGNUM].addr = num_pushes - 1;
605 for (from = AVR_LAST_PUSHED_REGNUM + 1 - (num_pushes - 2);
606 from <= AVR_LAST_PUSHED_REGNUM; ++from)
607 info->saved_regs [from].addr = ++i;
609 info->size = loc_size + num_pushes;
610 info->prologue_type = AVR_PROLOGUE_CALL;
612 return pc + pc_offset;
615 /* Scan for the beginning of the prologue for an interrupt or signal
616 function. Note that we have to set the prologue type here since the
617 third stage of the prologue may not be present (e.g. no saved registered
618 or changing of the SP register). */
622 unsigned char img[] = {
623 0x78, 0x94, /* sei */
624 0x1f, 0x92, /* push r1 */
625 0x0f, 0x92, /* push r0 */
626 0x0f, 0xb6, /* in r0,0x3f SREG */
627 0x0f, 0x92, /* push r0 */
628 0x11, 0x24 /* clr r1 */
630 if (memcmp (prologue, img, sizeof (img)) == 0)
632 info->prologue_type = AVR_PROLOGUE_INTR;
634 info->saved_regs[AVR_SREG_REGNUM].addr = 3;
635 info->saved_regs[0].addr = 2;
636 info->saved_regs[1].addr = 1;
639 else if (memcmp (img + 2, prologue, sizeof (img) - 2) == 0)
641 info->prologue_type = AVR_PROLOGUE_SIG;
642 vpc += sizeof (img) - 2;
643 info->saved_regs[AVR_SREG_REGNUM].addr = 3;
644 info->saved_regs[0].addr = 2;
645 info->saved_regs[1].addr = 1;
650 /* First stage of the prologue scanning.
651 Scan pushes (saved registers) */
653 for (; vpc < AVR_MAX_PROLOGUE_SIZE; vpc += 2)
655 insn = EXTRACT_INSN (&prologue[vpc]);
656 if ((insn & 0xfe0f) == 0x920f) /* push rXX */
658 /* Bits 4-9 contain a mask for registers R0-R32. */
659 int regno = (insn & 0x1f0) >> 4;
661 info->saved_regs[regno].addr = info->size;
668 if (vpc >= AVR_MAX_PROLOGUE_SIZE)
669 fprintf_unfiltered (gdb_stderr,
670 "Hit end of prologue while scanning pushes\n");
672 /* Second stage of the prologue scanning.
677 if (scan_stage == 1 && vpc < AVR_MAX_PROLOGUE_SIZE)
679 unsigned char img[] = {
680 0xcd, 0xb7, /* in r28,__SP_L__ */
681 0xde, 0xb7 /* in r29,__SP_H__ */
683 unsigned short insn1;
685 if (memcmp (prologue + vpc, img, sizeof (img)) == 0)
692 /* Third stage of the prologue scanning. (Really two stages)
694 sbiw r28,XX or subi r28,lo8(XX)
696 in __tmp_reg__,__SREG__
699 out __SREG__,__tmp_reg__
702 if (scan_stage == 2 && vpc < AVR_MAX_PROLOGUE_SIZE)
705 unsigned char img[] = {
706 0x0f, 0xb6, /* in r0,0x3f */
707 0xf8, 0x94, /* cli */
708 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
709 0x0f, 0xbe, /* out 0x3f,r0 ; SREG */
710 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
712 unsigned char img_sig[] = {
713 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
714 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
716 unsigned char img_int[] = {
717 0xf8, 0x94, /* cli */
718 0xde, 0xbf, /* out 0x3e,r29 ; SPH */
719 0x78, 0x94, /* sei */
720 0xcd, 0xbf /* out 0x3d,r28 ; SPL */
723 insn = EXTRACT_INSN (&prologue[vpc]);
725 if ((insn & 0xff30) == 0x9720) /* sbiw r28,XXX */
726 locals_size = (insn & 0xf) | ((insn & 0xc0) >> 2);
727 else if ((insn & 0xf0f0) == 0x50c0) /* subi r28,lo8(XX) */
729 locals_size = (insn & 0xf) | ((insn & 0xf00) >> 4);
730 insn = EXTRACT_INSN (&prologue[vpc]);
732 locals_size += ((insn & 0xf) | ((insn & 0xf00) >> 4) << 8);
737 /* Scan the last part of the prologue. May not be present for interrupt
738 or signal handler functions, which is why we set the prologue type
739 when we saw the beginning of the prologue previously. */
741 if (memcmp (prologue + vpc, img_sig, sizeof (img_sig)) == 0)
743 vpc += sizeof (img_sig);
745 else if (memcmp (prologue + vpc, img_int, sizeof (img_int)) == 0)
747 vpc += sizeof (img_int);
749 if (memcmp (prologue + vpc, img, sizeof (img)) == 0)
751 info->prologue_type = AVR_PROLOGUE_NORMAL;
755 info->size += locals_size;
757 return pc + avr_scan_arg_moves (vpc, prologue);
760 /* If we got this far, we could not scan the prologue, so just return the pc
761 of the frame plus an adjustment for argument move insns. */
763 return pc + avr_scan_arg_moves (vpc, prologue);;
767 avr_skip_prologue (CORE_ADDR pc)
769 CORE_ADDR func_addr, func_end;
770 CORE_ADDR prologue_end = pc;
772 /* See what the symbol table says */
774 if (find_pc_partial_function (pc, NULL, &func_addr, &func_end))
776 struct symtab_and_line sal;
777 struct avr_unwind_cache info = {0};
778 struct trad_frame_saved_reg saved_regs[AVR_NUM_REGS];
780 info.saved_regs = saved_regs;
782 /* Need to run the prologue scanner to figure out if the function has a
783 prologue and possibly skip over moving arguments passed via registers
784 to other registers. */
786 prologue_end = avr_scan_prologue (pc, &info);
788 if (info.prologue_type == AVR_PROLOGUE_NONE)
792 sal = find_pc_line (func_addr, 0);
794 if (sal.line != 0 && sal.end < func_end)
799 /* Either we didn't find the start of this function (nothing we can do),
800 or there's no line info, or the line after the prologue is after
801 the end of the function (there probably isn't a prologue). */
806 /* Not all avr devices support the BREAK insn. Those that don't should treat
807 it as a NOP. Thus, it should be ok. Since the avr is currently a remote
808 only target, this shouldn't be a problem (I hope). TRoth/2003-05-14 */
810 static const unsigned char *
811 avr_breakpoint_from_pc (CORE_ADDR * pcptr, int *lenptr)
813 static unsigned char avr_break_insn [] = { 0x98, 0x95 };
814 *lenptr = sizeof (avr_break_insn);
815 return avr_break_insn;
818 /* Given a return value in `regbuf' with a type `valtype',
819 extract and copy its value into `valbuf'.
821 Return values are always passed via registers r25:r24:... */
824 avr_extract_return_value (struct type *type, struct regcache *regcache,
830 if (TYPE_LENGTH (type) == 1)
832 regcache_cooked_read_unsigned (regcache, 24, &c);
833 store_unsigned_integer (valbuf, 1, c);
838 /* The MSB of the return value is always in r25, calculate which
839 register holds the LSB. */
840 int lsb_reg = 25 - TYPE_LENGTH (type) + 1;
842 for (i=0; i< TYPE_LENGTH (type); i++)
844 regcache_cooked_read (regcache, lsb_reg + i,
845 (bfd_byte *) valbuf + i);
850 /* Put here the code to store, into fi->saved_regs, the addresses of
851 the saved registers of frame described by FRAME_INFO. This
852 includes special registers such as pc and fp saved in special ways
853 in the stack frame. sp is even more special: the address we return
854 for it IS the sp for the next frame. */
856 struct avr_unwind_cache *
857 avr_frame_unwind_cache (struct frame_info *next_frame,
858 void **this_prologue_cache)
863 struct avr_unwind_cache *info;
866 if ((*this_prologue_cache))
867 return (*this_prologue_cache);
869 info = FRAME_OBSTACK_ZALLOC (struct avr_unwind_cache);
870 (*this_prologue_cache) = info;
871 info->saved_regs = trad_frame_alloc_saved_regs (next_frame);
874 info->prologue_type = AVR_PROLOGUE_NONE;
876 pc = frame_func_unwind (next_frame);
878 if ((pc > 0) && (pc < frame_pc_unwind (next_frame)))
879 avr_scan_prologue (pc, info);
881 if ((info->prologue_type != AVR_PROLOGUE_NONE)
882 && (info->prologue_type != AVR_PROLOGUE_MAIN))
884 ULONGEST high_base; /* High byte of FP */
886 /* The SP was moved to the FP. This indicates that a new frame
887 was created. Get THIS frame's FP value by unwinding it from
889 frame_unwind_unsigned_register (next_frame, AVR_FP_REGNUM, &this_base);
890 frame_unwind_unsigned_register (next_frame, AVR_FP_REGNUM+1, &high_base);
891 this_base += (high_base << 8);
893 /* The FP points at the last saved register. Adjust the FP back
894 to before the first saved register giving the SP. */
895 prev_sp = this_base + info->size;
899 /* Assume that the FP is this frame's SP but with that pushed
900 stack space added back. */
901 frame_unwind_unsigned_register (next_frame, AVR_SP_REGNUM, &this_base);
902 prev_sp = this_base + info->size;
905 /* Add 1 here to adjust for the post-decrement nature of the push
907 info->prev_sp = avr_make_saddr (prev_sp+1);
909 info->base = avr_make_saddr (this_base);
911 /* Adjust all the saved registers so that they contain addresses and not
913 for (i = 0; i < NUM_REGS - 1; i++)
914 if (info->saved_regs[i].addr)
916 info->saved_regs[i].addr = (info->prev_sp - info->saved_regs[i].addr);
919 /* Except for the main and startup code, the return PC is always saved on
920 the stack and is at the base of the frame. */
922 if (info->prologue_type != AVR_PROLOGUE_MAIN)
924 info->saved_regs[AVR_PC_REGNUM].addr = info->prev_sp;
927 /* The previous frame's SP needed to be computed. Save the computed
929 trad_frame_set_value (info->saved_regs, AVR_SP_REGNUM, info->prev_sp+1);
935 avr_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
939 frame_unwind_unsigned_register (next_frame, AVR_PC_REGNUM, &pc);
941 return avr_make_iaddr (pc);
944 /* Given a GDB frame, determine the address of the calling function's
945 frame. This will be used to create a new GDB frame struct. */
948 avr_frame_this_id (struct frame_info *next_frame,
949 void **this_prologue_cache,
950 struct frame_id *this_id)
952 struct avr_unwind_cache *info
953 = avr_frame_unwind_cache (next_frame, this_prologue_cache);
958 /* The FUNC is easy. */
959 func = frame_func_unwind (next_frame);
961 /* Hopefully the prologue analysis either correctly determined the
962 frame's base (which is the SP from the previous frame), or set
963 that base to "NULL". */
964 base = info->prev_sp;
968 id = frame_id_build (base, func);
970 /* Check that we're not going round in circles with the same frame
971 ID (but avoid applying the test to sentinel frames which do go
972 round in circles). Can't use frame_id_eq() as that doesn't yet
973 compare the frame's PC value. */
974 if (frame_relative_level (next_frame) >= 0
975 && get_frame_type (next_frame) != DUMMY_FRAME
976 && frame_id_eq (get_frame_id (next_frame), id))
983 avr_frame_prev_register (struct frame_info *next_frame,
984 void **this_prologue_cache,
985 int regnum, int *optimizedp,
986 enum lval_type *lvalp, CORE_ADDR *addrp,
987 int *realnump, void *bufferp)
989 struct avr_unwind_cache *info
990 = avr_frame_unwind_cache (next_frame, this_prologue_cache);
992 if (regnum == AVR_PC_REGNUM)
994 if (trad_frame_addr_p (info->saved_regs, regnum))
997 *lvalp = lval_memory;
998 *addrp = info->saved_regs[regnum].addr;
1000 if (bufferp != NULL)
1002 /* Reading the return PC from the PC register is slightly
1003 abnormal. register_size(AVR_PC_REGNUM) says it is 4 bytes,
1004 but in reality, only two bytes (3 in upcoming mega256) are
1005 stored on the stack.
1007 Also, note that the value on the stack is an addr to a word
1008 not a byte, so we will need to multiply it by two at some
1011 And to confuse matters even more, the return address stored
1012 on the stack is in big endian byte order, even though most
1013 everything else about the avr is little endian. Ick! */
1015 /* FIXME: number of bytes read here will need updated for the
1016 mega256 when it is available. */
1020 unsigned char buf[2];
1022 read_memory (info->saved_regs[regnum].addr, buf, 2);
1024 /* Convert the PC read from memory as a big-endian to
1025 little-endian order. */
1030 pc = (extract_unsigned_integer (buf, 2) * 2);
1031 store_unsigned_integer (bufferp,
1032 register_size (current_gdbarch, regnum),
1038 trad_frame_prev_register (next_frame, info->saved_regs, regnum,
1039 optimizedp, lvalp, addrp, realnump, bufferp);
1042 static const struct frame_unwind avr_frame_unwind = {
1045 avr_frame_prev_register
1048 const struct frame_unwind *
1049 avr_frame_sniffer (struct frame_info *next_frame)
1051 return &avr_frame_unwind;
1055 avr_frame_base_address (struct frame_info *next_frame, void **this_cache)
1057 struct avr_unwind_cache *info
1058 = avr_frame_unwind_cache (next_frame, this_cache);
1063 static const struct frame_base avr_frame_base = {
1065 avr_frame_base_address,
1066 avr_frame_base_address,
1067 avr_frame_base_address
1070 /* Assuming NEXT_FRAME->prev is a dummy, return the frame ID of that
1071 dummy frame. The frame ID's base needs to match the TOS value
1072 saved by save_dummy_frame_tos(), and the PC match the dummy frame's
1075 static struct frame_id
1076 avr_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame)
1080 frame_unwind_unsigned_register (next_frame, AVR_SP_REGNUM, &base);
1081 return frame_id_build (avr_make_saddr (base), frame_pc_unwind (next_frame));
1084 /* When arguments must be pushed onto the stack, they go on in reverse
1085 order. The below implements a FILO (stack) to do this. */
1090 struct stack_item *prev;
1094 static struct stack_item *push_stack_item (struct stack_item *prev,
1095 void *contents, int len);
1096 static struct stack_item *
1097 push_stack_item (struct stack_item *prev, void *contents, int len)
1099 struct stack_item *si;
1100 si = xmalloc (sizeof (struct stack_item));
1101 si->data = xmalloc (len);
1104 memcpy (si->data, contents, len);
1108 static struct stack_item *pop_stack_item (struct stack_item *si);
1109 static struct stack_item *
1110 pop_stack_item (struct stack_item *si)
1112 struct stack_item *dead = si;
1119 /* Setup the function arguments for calling a function in the inferior.
1121 On the AVR architecture, there are 18 registers (R25 to R8) which are
1122 dedicated for passing function arguments. Up to the first 18 arguments
1123 (depending on size) may go into these registers. The rest go on the stack.
1125 All arguments are aligned to start in even-numbered registers (odd-sized
1126 arguments, including char, have one free register above them). For example,
1127 an int in arg1 and a char in arg2 would be passed as such:
1132 Arguments that are larger than 2 bytes will be split between two or more
1133 registers as available, but will NOT be split between a register and the
1134 stack. Arguments that go onto the stack are pushed last arg first (this is
1135 similar to the d10v). */
1137 /* NOTE: TRoth/2003-06-17: The rest of this comment is old looks to be
1140 An exceptional case exists for struct arguments (and possibly other
1141 aggregates such as arrays) -- if the size is larger than WORDSIZE bytes but
1142 not a multiple of WORDSIZE bytes. In this case the argument is never split
1143 between the registers and the stack, but instead is copied in its entirety
1144 onto the stack, AND also copied into as many registers as there is room
1145 for. In other words, space in registers permitting, two copies of the same
1146 argument are passed in. As far as I can tell, only the one on the stack is
1147 used, although that may be a function of the level of compiler
1148 optimization. I suspect this is a compiler bug. Arguments of these odd
1149 sizes are left-justified within the word (as opposed to arguments smaller
1150 than WORDSIZE bytes, which are right-justified).
1152 If the function is to return an aggregate type such as a struct, the caller
1153 must allocate space into which the callee will copy the return value. In
1154 this case, a pointer to the return value location is passed into the callee
1155 in register R0, which displaces one of the other arguments passed in via
1156 registers R0 to R2. */
1159 avr_push_dummy_call (struct gdbarch *gdbarch, CORE_ADDR func_addr,
1160 struct regcache *regcache, CORE_ADDR bp_addr,
1161 int nargs, struct value **args, CORE_ADDR sp,
1162 int struct_return, CORE_ADDR struct_addr)
1165 unsigned char buf[2];
1166 CORE_ADDR return_pc = avr_convert_iaddr_to_raw (bp_addr);
1167 int regnum = AVR_ARGN_REGNUM;
1168 struct stack_item *si = NULL;
1171 /* FIXME: TRoth/2003-06-18: Not sure what to do when returning a struct. */
1174 fprintf_unfiltered (gdb_stderr, "struct_return: 0x%lx\n", struct_addr);
1175 write_register (argreg--, struct_addr & 0xff);
1176 write_register (argreg--, (struct_addr >>8) & 0xff);
1180 for (i = 0; i < nargs; i++)
1184 struct value *arg = args[i];
1185 struct type *type = check_typedef (VALUE_TYPE (arg));
1186 char *contents = VALUE_CONTENTS (arg);
1187 int len = TYPE_LENGTH (type);
1189 /* Calculate the potential last register needed. */
1190 last_regnum = regnum - (len + (len & 1));
1192 /* If there are registers available, use them. Once we start putting
1193 stuff on the stack, all subsequent args go on stack. */
1194 if ((si == NULL) && (last_regnum >= 8))
1198 /* Skip a register for odd length args. */
1202 val = extract_unsigned_integer (contents, len);
1203 for (j=0; j<len; j++)
1205 regcache_cooked_write_unsigned (regcache, regnum--,
1206 val >> (8*(len-j-1)));
1209 /* No registers available, push the args onto the stack. */
1212 /* From here on, we don't care about regnum. */
1213 si = push_stack_item (si, contents, len);
1217 /* Push args onto the stack. */
1221 /* Add 1 to sp here to account for post decr nature of pushes. */
1222 write_memory (sp+1, si->data, si->len);
1223 si = pop_stack_item (si);
1226 /* Set the return address. For the avr, the return address is the BP_ADDR.
1227 Need to push the return address onto the stack noting that it needs to be
1228 in big-endian order on the stack. */
1229 buf[0] = (return_pc >> 8) & 0xff;
1230 buf[1] = return_pc & 0xff;
1233 write_memory (sp+1, buf, 2); /* Add one since pushes are post decr ops. */
1235 /* Finally, update the SP register. */
1236 regcache_cooked_write_unsigned (regcache, AVR_SP_REGNUM,
1237 avr_convert_saddr_to_raw (sp));
1242 /* Initialize the gdbarch structure for the AVR's. */
1244 static struct gdbarch *
1245 avr_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
1247 struct gdbarch *gdbarch;
1248 struct gdbarch_tdep *tdep;
1250 /* Find a candidate among the list of pre-declared architectures. */
1251 arches = gdbarch_list_lookup_by_info (arches, &info);
1253 return arches->gdbarch;
1255 /* None found, create a new architecture from the information provided. */
1256 tdep = XMALLOC (struct gdbarch_tdep);
1257 gdbarch = gdbarch_alloc (&info, tdep);
1259 /* If we ever need to differentiate the device types, do it here. */
1260 switch (info.bfd_arch_info->mach)
1270 set_gdbarch_short_bit (gdbarch, 2 * TARGET_CHAR_BIT);
1271 set_gdbarch_int_bit (gdbarch, 2 * TARGET_CHAR_BIT);
1272 set_gdbarch_long_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1273 set_gdbarch_long_long_bit (gdbarch, 8 * TARGET_CHAR_BIT);
1274 set_gdbarch_ptr_bit (gdbarch, 2 * TARGET_CHAR_BIT);
1275 set_gdbarch_addr_bit (gdbarch, 32);
1277 set_gdbarch_float_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1278 set_gdbarch_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1279 set_gdbarch_long_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
1281 set_gdbarch_float_format (gdbarch, &floatformat_ieee_single_little);
1282 set_gdbarch_double_format (gdbarch, &floatformat_ieee_single_little);
1283 set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_single_little);
1285 set_gdbarch_read_pc (gdbarch, avr_read_pc);
1286 set_gdbarch_write_pc (gdbarch, avr_write_pc);
1287 set_gdbarch_read_sp (gdbarch, avr_read_sp);
1289 set_gdbarch_num_regs (gdbarch, AVR_NUM_REGS);
1291 set_gdbarch_sp_regnum (gdbarch, AVR_SP_REGNUM);
1292 set_gdbarch_pc_regnum (gdbarch, AVR_PC_REGNUM);
1294 set_gdbarch_register_name (gdbarch, avr_register_name);
1295 set_gdbarch_register_type (gdbarch, avr_register_type);
1297 set_gdbarch_extract_return_value (gdbarch, avr_extract_return_value);
1298 set_gdbarch_print_insn (gdbarch, print_insn_avr);
1300 set_gdbarch_push_dummy_call (gdbarch, avr_push_dummy_call);
1302 set_gdbarch_address_to_pointer (gdbarch, avr_address_to_pointer);
1303 set_gdbarch_pointer_to_address (gdbarch, avr_pointer_to_address);
1305 set_gdbarch_use_struct_convention (gdbarch, generic_use_struct_convention);
1307 set_gdbarch_skip_prologue (gdbarch, avr_skip_prologue);
1308 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
1310 set_gdbarch_breakpoint_from_pc (gdbarch, avr_breakpoint_from_pc);
1312 set_gdbarch_frameless_function_invocation (gdbarch,
1313 frameless_look_for_prologue);
1315 frame_unwind_append_sniffer (gdbarch, avr_frame_sniffer);
1316 frame_base_set_default (gdbarch, &avr_frame_base);
1318 set_gdbarch_unwind_dummy_id (gdbarch, avr_unwind_dummy_id);
1320 set_gdbarch_unwind_pc (gdbarch, avr_unwind_pc);
1325 /* Send a query request to the avr remote target asking for values of the io
1326 registers. If args parameter is not NULL, then the user has requested info
1327 on a specific io register [This still needs implemented and is ignored for
1328 now]. The query string should be one of these forms:
1330 "Ravr.io_reg" -> reply is "NN" number of io registers
1332 "Ravr.io_reg:addr,len" where addr is first register and len is number of
1333 registers to be read. The reply should be "<NAME>,VV;" for each io register
1334 where, <NAME> is a string, and VV is the hex value of the register.
1336 All io registers are 8-bit. */
1339 avr_io_reg_read_command (char *args, int from_tty)
1345 unsigned int nreg = 0;
1349 /* Just get the maximum buffer size. */
1350 bufsiz = target_read_partial (¤t_target, TARGET_OBJECT_AVR,
1354 fprintf_unfiltered (gdb_stderr,
1355 "ERR: info io_registers NOT supported by current "
1359 if (bufsiz > sizeof (buf))
1360 bufsiz = sizeof (buf);
1362 /* Find out how many io registers the target has. */
1363 strcpy (query, "avr.io_reg");
1364 target_read_partial (¤t_target, TARGET_OBJECT_AVR, query, buf, 0,
1367 if (strncmp (buf, "", bufsiz) == 0)
1369 fprintf_unfiltered (gdb_stderr,
1370 "info io_registers NOT supported by target\n");
1374 if (sscanf (buf, "%x", &nreg) != 1)
1376 fprintf_unfiltered (gdb_stderr,
1377 "Error fetching number of io registers\n");
1381 reinitialize_more_filter ();
1383 printf_unfiltered ("Target has %u io registers:\n\n", nreg);
1385 /* only fetch up to 8 registers at a time to keep the buffer small */
1388 for (i = 0; i < nreg; i += step)
1390 /* how many registers this round? */
1393 j = nreg - i; /* last block is less than 8 registers */
1395 snprintf (query, sizeof (query) - 1, "avr.io_reg:%x,%x", i, j);
1396 target_read_partial (¤t_target, TARGET_OBJECT_AVR, query, buf,
1400 for (k = i; k < (i + j); k++)
1402 if (sscanf (p, "%[^,],%x;", query, &val) == 2)
1404 printf_filtered ("[%02x] %-15s : %02x\n", k, query, val);
1405 while ((*p != ';') && (*p != '\0'))
1407 p++; /* skip over ';' */
1415 extern initialize_file_ftype _initialize_avr_tdep; /* -Wmissing-prototypes */
1418 _initialize_avr_tdep (void)
1420 register_gdbarch_init (bfd_arch_avr, avr_gdbarch_init);
1422 /* Add a new command to allow the user to query the avr remote target for
1423 the values of the io space registers in a saner way than just using
1426 /* FIXME: TRoth/2002-02-18: This should probably be changed to 'info avr
1427 io_registers' to signify it is not available on other platforms. */
1429 add_cmd ("io_registers", class_info, avr_io_reg_read_command,
1430 "query remote avr target for io space register values", &infolist);