599 lines
18 KiB
C
599 lines
18 KiB
C
/* Target-dependent code for the Fujitsu FR30.
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Copyright 1999, Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "frame.h"
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#include "inferior.h"
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#include "obstack.h"
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#include "target.h"
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#include "value.h"
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#include "bfd.h"
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#include "gdb_string.h"
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#include "gdbcore.h"
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#include "symfile.h"
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/* An expression that tells us whether the function invocation represented
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by FI does not have a frame on the stack associated with it. */
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int
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fr30_frameless_function_invocation (struct frame_info *fi)
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{
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int frameless;
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CORE_ADDR func_start, after_prologue;
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func_start = (get_pc_function_start ((fi)->pc) +
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FUNCTION_START_OFFSET);
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after_prologue = func_start;
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after_prologue = SKIP_PROLOGUE (after_prologue);
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frameless = (after_prologue == func_start);
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return frameless;
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}
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/* Function: pop_frame
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This routine gets called when either the user uses the `return'
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command, or the call dummy breakpoint gets hit. */
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void
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fr30_pop_frame (void)
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{
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struct frame_info *frame = get_current_frame ();
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int regnum;
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CORE_ADDR sp = read_register (SP_REGNUM);
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if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame))
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generic_pop_dummy_frame ();
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else
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{
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write_register (PC_REGNUM, FRAME_SAVED_PC (frame));
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for (regnum = 0; regnum < NUM_REGS; regnum++)
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if (frame->fsr.regs[regnum] != 0)
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{
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write_register (regnum,
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read_memory_unsigned_integer (frame->fsr.regs[regnum],
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REGISTER_RAW_SIZE (regnum)));
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}
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write_register (SP_REGNUM, sp + frame->framesize);
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}
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flush_cached_frames ();
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}
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/* Function: fr30_store_return_value
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Put a value where a caller expects to see it. Used by the 'return'
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command. */
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void
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fr30_store_return_value (struct type *type,
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char *valbuf)
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{
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/* Here's how the FR30 returns values (gleaned from gcc/config/
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fr30/fr30.h):
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If the return value is 32 bits long or less, it goes in r4.
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If the return value is 64 bits long or less, it goes in r4 (most
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significant word) and r5 (least significant word.
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If the function returns a structure, of any size, the caller
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passes the function an invisible first argument where the callee
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should store the value. But GDB doesn't let you do that anyway.
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If you're returning a value smaller than a word, it's not really
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necessary to zero the upper bytes of the register; the caller is
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supposed to ignore them. However, the FR30 typically keeps its
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values extended to the full register width, so we should emulate
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that. */
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/* The FR30 is big-endian, so if we return a small value (like a
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short or a char), we need to position it correctly within the
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register. We round the size up to a register boundary, and then
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adjust the offset so as to place the value at the right end. */
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int value_size = TYPE_LENGTH (type);
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int returned_size = (value_size + FR30_REGSIZE - 1) & ~(FR30_REGSIZE - 1);
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int offset = (REGISTER_BYTE (RETVAL_REG)
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+ (returned_size - value_size));
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char *zeros = alloca (returned_size);
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memset (zeros, 0, returned_size);
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write_register_bytes (REGISTER_BYTE (RETVAL_REG), zeros, returned_size);
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write_register_bytes (offset, valbuf, value_size);
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}
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/* Function: skip_prologue
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Return the address of the first code past the prologue of the function. */
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CORE_ADDR
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fr30_skip_prologue (CORE_ADDR pc)
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{
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CORE_ADDR func_addr, func_end;
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/* See what the symbol table says */
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if (find_pc_partial_function (pc, NULL, &func_addr, &func_end))
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{
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struct symtab_and_line sal;
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sal = find_pc_line (func_addr, 0);
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if (sal.line != 0 && sal.end < func_end)
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{
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return sal.end;
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}
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}
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/* Either we didn't find the start of this function (nothing we can do),
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or there's no line info, or the line after the prologue is after
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the end of the function (there probably isn't a prologue). */
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return pc;
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}
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/* Function: push_arguments
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Setup arguments and RP for a call to the target. First four args
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go in FIRST_ARGREG -> LAST_ARGREG, subsequent args go on stack...
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Structs are passed by reference. XXX not right now Z.R.
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64 bit quantities (doubles and long longs) may be split between
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the regs and the stack.
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When calling a function that returns a struct, a pointer to the struct
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is passed in as a secret first argument (always in FIRST_ARGREG).
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Stack space for the args has NOT been allocated: that job is up to us.
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*/
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CORE_ADDR
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fr30_push_arguments (int nargs, value_ptr *args, CORE_ADDR sp,
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int struct_return, CORE_ADDR struct_addr)
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{
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int argreg;
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int argnum;
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int stack_offset;
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struct stack_arg
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{
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char *val;
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int len;
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int offset;
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};
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struct stack_arg *stack_args =
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(struct stack_arg *) alloca (nargs * sizeof (struct stack_arg));
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int nstack_args = 0;
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argreg = FIRST_ARGREG;
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/* the struct_return pointer occupies the first parameter-passing reg */
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if (struct_return)
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write_register (argreg++, struct_addr);
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stack_offset = 0;
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/* Process args from left to right. Store as many as allowed in
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registers, save the rest to be pushed on the stack */
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for (argnum = 0; argnum < nargs; argnum++)
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{
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char *val;
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value_ptr arg = args[argnum];
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struct type *arg_type = check_typedef (VALUE_TYPE (arg));
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struct type *target_type = TYPE_TARGET_TYPE (arg_type);
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int len = TYPE_LENGTH (arg_type);
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enum type_code typecode = TYPE_CODE (arg_type);
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CORE_ADDR regval;
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int newarg;
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val = (char *) VALUE_CONTENTS (arg);
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{
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/* Copy the argument to general registers or the stack in
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register-sized pieces. Large arguments are split between
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registers and stack. */
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while (len > 0)
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{
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if (argreg <= LAST_ARGREG)
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{
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int partial_len = len < REGISTER_SIZE ? len : REGISTER_SIZE;
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regval = extract_address (val, partial_len);
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/* It's a simple argument being passed in a general
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register. */
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write_register (argreg, regval);
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argreg++;
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len -= partial_len;
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val += partial_len;
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}
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else
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{
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/* keep for later pushing */
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stack_args[nstack_args].val = val;
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stack_args[nstack_args++].len = len;
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break;
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}
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}
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}
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}
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/* now do the real stack pushing, process args right to left */
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while (nstack_args--)
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{
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sp -= stack_args[nstack_args].len;
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write_memory (sp, stack_args[nstack_args].val,
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stack_args[nstack_args].len);
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}
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/* Return adjusted stack pointer. */
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return sp;
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}
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void _initialize_fr30_tdep (void);
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void
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_initialize_fr30_tdep (void)
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{
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extern int print_insn_fr30 (bfd_vma, disassemble_info *);
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tm_print_insn = print_insn_fr30;
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}
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/* Function: check_prologue_cache
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Check if prologue for this frame's PC has already been scanned.
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If it has, copy the relevant information about that prologue and
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return non-zero. Otherwise do not copy anything and return zero.
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The information saved in the cache includes:
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* the frame register number;
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* the size of the stack frame;
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* the offsets of saved regs (relative to the old SP); and
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* the offset from the stack pointer to the frame pointer
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The cache contains only one entry, since this is adequate
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for the typical sequence of prologue scan requests we get.
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When performing a backtrace, GDB will usually ask to scan
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the same function twice in a row (once to get the frame chain,
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and once to fill in the extra frame information).
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*/
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static struct frame_info prologue_cache;
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static int
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check_prologue_cache (struct frame_info *fi)
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{
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int i;
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if (fi->pc == prologue_cache.pc)
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{
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fi->framereg = prologue_cache.framereg;
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fi->framesize = prologue_cache.framesize;
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fi->frameoffset = prologue_cache.frameoffset;
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for (i = 0; i <= NUM_REGS; i++)
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fi->fsr.regs[i] = prologue_cache.fsr.regs[i];
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return 1;
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}
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else
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return 0;
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}
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/* Function: save_prologue_cache
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Copy the prologue information from fi to the prologue cache.
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*/
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static void
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save_prologue_cache (struct frame_info *fi)
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{
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int i;
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prologue_cache.pc = fi->pc;
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prologue_cache.framereg = fi->framereg;
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prologue_cache.framesize = fi->framesize;
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prologue_cache.frameoffset = fi->frameoffset;
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for (i = 0; i <= NUM_REGS; i++)
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{
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prologue_cache.fsr.regs[i] = fi->fsr.regs[i];
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}
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}
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/* Function: scan_prologue
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Scan the prologue of the function that contains PC, and record what
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we find in PI. PI->fsr must be zeroed by the called. Returns the
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pc after the prologue. Note that the addresses saved in pi->fsr
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are actually just frame relative (negative offsets from the frame
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pointer). This is because we don't know the actual value of the
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frame pointer yet. In some circumstances, the frame pointer can't
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be determined till after we have scanned the prologue. */
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static void
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fr30_scan_prologue (struct frame_info *fi)
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{
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int sp_offset, fp_offset;
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CORE_ADDR prologue_start, prologue_end, current_pc;
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/* Check if this function is already in the cache of frame information. */
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if (check_prologue_cache (fi))
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return;
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/* Assume there is no frame until proven otherwise. */
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fi->framereg = SP_REGNUM;
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fi->framesize = 0;
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fi->frameoffset = 0;
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/* Find the function prologue. If we can't find the function in
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the symbol table, peek in the stack frame to find the PC. */
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if (find_pc_partial_function (fi->pc, NULL, &prologue_start, &prologue_end))
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{
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/* Assume the prologue is everything between the first instruction
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in the function and the first source line. */
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struct symtab_and_line sal = find_pc_line (prologue_start, 0);
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if (sal.line == 0) /* no line info, use current PC */
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prologue_end = fi->pc;
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else if (sal.end < prologue_end) /* next line begins after fn end */
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prologue_end = sal.end; /* (probably means no prologue) */
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}
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else
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{
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/* XXX Z.R. What now??? The following is entirely bogus */
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prologue_start = (read_memory_integer (fi->frame, 4) & 0x03fffffc) - 12;
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prologue_end = prologue_start + 40;
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}
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/* Now search the prologue looking for instructions that set up the
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frame pointer, adjust the stack pointer, and save registers. */
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sp_offset = fp_offset = 0;
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for (current_pc = prologue_start; current_pc < prologue_end; current_pc += 2)
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{
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unsigned int insn;
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insn = read_memory_unsigned_integer (current_pc, 2);
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if ((insn & 0xfe00) == 0x8e00) /* stm0 or stm1 */
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{
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int reg, mask = insn & 0xff;
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/* scan in one sweep - create virtual 16-bit mask from either insn's mask */
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if ((insn & 0x0100) == 0)
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{
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mask <<= 8; /* stm0 - move to upper byte in virtual mask */
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}
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/* Calculate offsets of saved registers (to be turned later into addresses). */
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for (reg = R4_REGNUM; reg <= R11_REGNUM; reg++)
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if (mask & (1 << (15 - reg)))
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{
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sp_offset -= 4;
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fi->fsr.regs[reg] = sp_offset;
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}
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}
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else if ((insn & 0xfff0) == 0x1700) /* st rx,@-r15 */
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{
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int reg = insn & 0xf;
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sp_offset -= 4;
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fi->fsr.regs[reg] = sp_offset;
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}
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else if ((insn & 0xff00) == 0x0f00) /* enter */
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{
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fp_offset = fi->fsr.regs[FP_REGNUM] = sp_offset - 4;
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sp_offset -= 4 * (insn & 0xff);
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fi->framereg = FP_REGNUM;
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}
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else if (insn == 0x1781) /* st rp,@-sp */
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{
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sp_offset -= 4;
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fi->fsr.regs[RP_REGNUM] = sp_offset;
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}
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else if (insn == 0x170e) /* st fp,@-sp */
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{
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sp_offset -= 4;
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fi->fsr.regs[FP_REGNUM] = sp_offset;
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}
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else if (insn == 0x8bfe) /* mov sp,fp */
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{
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fi->framereg = FP_REGNUM;
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}
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else if ((insn & 0xff00) == 0xa300) /* addsp xx */
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{
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sp_offset += 4 * (signed char) (insn & 0xff);
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}
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else if ((insn & 0xff0f) == 0x9b00 && /* ldi:20 xx,r0 */
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read_memory_unsigned_integer (current_pc + 4, 2)
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== 0xac0f) /* sub r0,sp */
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{
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/* large stack adjustment */
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sp_offset -= (((insn & 0xf0) << 12) | read_memory_unsigned_integer (current_pc + 2, 2));
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current_pc += 4;
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}
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else if (insn == 0x9f80 && /* ldi:32 xx,r0 */
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read_memory_unsigned_integer (current_pc + 6, 2)
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== 0xac0f) /* sub r0,sp */
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{
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/* large stack adjustment */
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sp_offset -=
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(read_memory_unsigned_integer (current_pc + 2, 2) << 16 |
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read_memory_unsigned_integer (current_pc + 4, 2));
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current_pc += 6;
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}
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}
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/* The frame size is just the negative of the offset (from the original SP)
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of the last thing thing we pushed on the stack. The frame offset is
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[new FP] - [new SP]. */
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fi->framesize = -sp_offset;
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fi->frameoffset = fp_offset - sp_offset;
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save_prologue_cache (fi);
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}
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/* Function: init_extra_frame_info
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Setup the frame's frame pointer, pc, and frame addresses for saved
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registers. Most of the work is done in scan_prologue().
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Note that when we are called for the last frame (currently active frame),
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that fi->pc and fi->frame will already be setup. However, fi->frame will
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be valid only if this routine uses FP. For previous frames, fi-frame will
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always be correct (since that is derived from fr30_frame_chain ()).
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We can be called with the PC in the call dummy under two circumstances.
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First, during normal backtracing, second, while figuring out the frame
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pointer just prior to calling the target function (see run_stack_dummy). */
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void
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fr30_init_extra_frame_info (struct frame_info *fi)
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{
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int reg;
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if (fi->next)
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fi->pc = FRAME_SAVED_PC (fi->next);
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memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs);
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if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
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{
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/* We need to setup fi->frame here because run_stack_dummy gets it wrong
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by assuming it's always FP. */
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fi->frame = generic_read_register_dummy (fi->pc, fi->frame, SP_REGNUM);
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fi->framesize = 0;
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fi->frameoffset = 0;
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return;
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}
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fr30_scan_prologue (fi);
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if (!fi->next) /* this is the innermost frame? */
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fi->frame = read_register (fi->framereg);
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else
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/* not the innermost frame */
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/* If we have an FP, the callee saved it. */ if (fi->framereg == FP_REGNUM)
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if (fi->next->fsr.regs[fi->framereg] != 0)
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fi->frame = read_memory_integer (fi->next->fsr.regs[fi->framereg],
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4);
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/* Calculate actual addresses of saved registers using offsets determined
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by fr30_scan_prologue. */
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for (reg = 0; reg < NUM_REGS; reg++)
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if (fi->fsr.regs[reg] != 0)
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{
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fi->fsr.regs[reg] += fi->frame + fi->framesize - fi->frameoffset;
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}
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}
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/* Function: find_callers_reg
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Find REGNUM on the stack. Otherwise, it's in an active register.
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One thing we might want to do here is to check REGNUM against the
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clobber mask, and somehow flag it as invalid if it isn't saved on
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the stack somewhere. This would provide a graceful failure mode
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when trying to get the value of caller-saves registers for an inner
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frame. */
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CORE_ADDR
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fr30_find_callers_reg (struct frame_info *fi, int regnum)
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{
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for (; fi; fi = fi->next)
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if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
|
|
return generic_read_register_dummy (fi->pc, fi->frame, regnum);
|
|
else if (fi->fsr.regs[regnum] != 0)
|
|
return read_memory_unsigned_integer (fi->fsr.regs[regnum],
|
|
REGISTER_RAW_SIZE (regnum));
|
|
|
|
return read_register (regnum);
|
|
}
|
|
|
|
|
|
/* Function: frame_chain
|
|
Figure out the frame prior to FI. Unfortunately, this involves
|
|
scanning the prologue of the caller, which will also be done
|
|
shortly by fr30_init_extra_frame_info. For the dummy frame, we
|
|
just return the stack pointer that was in use at the time the
|
|
function call was made. */
|
|
|
|
|
|
CORE_ADDR
|
|
fr30_frame_chain (struct frame_info *fi)
|
|
{
|
|
CORE_ADDR fn_start, callers_pc, fp;
|
|
struct frame_info caller_fi;
|
|
int framereg;
|
|
|
|
/* is this a dummy frame? */
|
|
if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
|
|
return fi->frame; /* dummy frame same as caller's frame */
|
|
|
|
/* is caller-of-this a dummy frame? */
|
|
callers_pc = FRAME_SAVED_PC (fi); /* find out who called us: */
|
|
fp = fr30_find_callers_reg (fi, FP_REGNUM);
|
|
if (PC_IN_CALL_DUMMY (callers_pc, fp, fp))
|
|
return fp; /* dummy frame's frame may bear no relation to ours */
|
|
|
|
if (find_pc_partial_function (fi->pc, 0, &fn_start, 0))
|
|
if (fn_start == entry_point_address ())
|
|
return 0; /* in _start fn, don't chain further */
|
|
|
|
framereg = fi->framereg;
|
|
|
|
/* If the caller is the startup code, we're at the end of the chain. */
|
|
if (find_pc_partial_function (callers_pc, 0, &fn_start, 0))
|
|
if (fn_start == entry_point_address ())
|
|
return 0;
|
|
|
|
memset (&caller_fi, 0, sizeof (caller_fi));
|
|
caller_fi.pc = callers_pc;
|
|
fr30_scan_prologue (&caller_fi);
|
|
framereg = caller_fi.framereg;
|
|
|
|
/* If the caller used a frame register, return its value.
|
|
Otherwise, return the caller's stack pointer. */
|
|
if (framereg == FP_REGNUM)
|
|
return fr30_find_callers_reg (fi, framereg);
|
|
else
|
|
return fi->frame + fi->framesize;
|
|
}
|
|
|
|
/* Function: frame_saved_pc
|
|
Find the caller of this frame. We do this by seeing if RP_REGNUM
|
|
is saved in the stack anywhere, otherwise we get it from the
|
|
registers. If the inner frame is a dummy frame, return its PC
|
|
instead of RP, because that's where "caller" of the dummy-frame
|
|
will be found. */
|
|
|
|
CORE_ADDR
|
|
fr30_frame_saved_pc (struct frame_info *fi)
|
|
{
|
|
if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
|
|
return generic_read_register_dummy (fi->pc, fi->frame, PC_REGNUM);
|
|
else
|
|
return fr30_find_callers_reg (fi, RP_REGNUM);
|
|
}
|
|
|
|
/* Function: fix_call_dummy
|
|
Pokes the callee function's address into the CALL_DUMMY assembly stub.
|
|
Assumes that the CALL_DUMMY looks like this:
|
|
jarl <offset24>, r31
|
|
trap
|
|
*/
|
|
|
|
int
|
|
fr30_fix_call_dummy (char *dummy, CORE_ADDR sp, CORE_ADDR fun, int nargs,
|
|
value_ptr *args, struct type *type, int gcc_p)
|
|
{
|
|
long offset24;
|
|
|
|
offset24 = (long) fun - (long) entry_point_address ();
|
|
offset24 &= 0x3fffff;
|
|
offset24 |= 0xff800000; /* jarl <offset24>, r31 */
|
|
|
|
store_unsigned_integer ((unsigned int *) &dummy[2], 2, offset24 & 0xffff);
|
|
store_unsigned_integer ((unsigned int *) &dummy[0], 2, offset24 >> 16);
|
|
return 0;
|
|
}
|