739 lines
22 KiB
C
739 lines
22 KiB
C
/* Target-dependent code for the Mitsubishi m32r for GDB, the GNU debugger.
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Copyright 1996, 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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/* Function: m32r_use_struct_convention
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Return nonzero if call_function should allocate stack space for a
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struct return? */
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int
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m32r_use_struct_convention (gcc_p, type)
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int gcc_p;
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struct type *type;
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{
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return (TYPE_LENGTH (type) > 8);
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}
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/* Function: frame_find_saved_regs
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Return the frame_saved_regs structure for the frame.
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Doesn't really work for dummy frames, but it does pass back
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an empty frame_saved_regs, so I guess that's better than total failure */
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void
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m32r_frame_find_saved_regs (fi, regaddr)
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struct frame_info *fi;
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struct frame_saved_regs *regaddr;
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{
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memcpy (regaddr, &fi->fsr, sizeof (struct frame_saved_regs));
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}
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/* Turn this on if you want to see just how much instruction decoding
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if being done, its quite a lot
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*/
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#if 0
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static void
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dump_insn (char *commnt, CORE_ADDR pc, int insn)
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{
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printf_filtered (" %s %08x %08x ",
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commnt, (unsigned int) pc, (unsigned int) insn);
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(*tm_print_insn) (pc, &tm_print_insn_info);
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printf_filtered ("\n");
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}
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#define insn_debug(args) { printf_filtered args; }
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#else
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#define dump_insn(a,b,c) {}
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#define insn_debug(args) {}
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#endif
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#define DEFAULT_SEARCH_LIMIT 44
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/* Function: scan_prologue
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This function decodes the target function prologue to determine
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1) the size of the stack frame, and 2) which registers are saved on it.
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It saves the offsets of saved regs in the frame_saved_regs argument,
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and returns the frame size. */
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/*
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The sequence it currently generates is:
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if (varargs function) { ddi sp,#n }
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push registers
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if (additional stack <= 256) { addi sp,#-stack }
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else if (additional stack < 65k) { add3 sp,sp,#-stack
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} else if (additional stack) {
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seth sp,#(stack & 0xffff0000)
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or3 sp,sp,#(stack & 0x0000ffff)
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sub sp,r4
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}
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if (frame pointer) {
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mv sp,fp
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}
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These instructions are scheduled like everything else, so you should stop at
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the first branch instruction.
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*/
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/* This is required by skip prologue and by m32r_init_extra_frame_info.
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The results of decoding a prologue should be cached because this
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thrashing is getting nuts.
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I am thinking of making a container class with two indexes, name and
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address. It may be better to extend the symbol table.
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*/
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static void
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decode_prologue (start_pc, scan_limit,
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pl_endptr, framelength,
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fi, fsr)
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CORE_ADDR start_pc;
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CORE_ADDR scan_limit;
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CORE_ADDR *pl_endptr; /* var parameter */
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unsigned long *framelength;
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struct frame_info *fi;
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struct frame_saved_regs *fsr;
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{
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unsigned long framesize;
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int insn;
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int op1;
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int maybe_one_more = 0;
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CORE_ADDR after_prologue = 0;
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CORE_ADDR after_stack_adjust = 0;
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CORE_ADDR current_pc;
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framesize = 0;
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after_prologue = 0;
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insn_debug (("rd prolog l(%d)\n", scan_limit - current_pc));
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for (current_pc = start_pc; current_pc < scan_limit; current_pc += 2)
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{
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insn = read_memory_unsigned_integer (current_pc, 2);
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dump_insn ("insn-1", current_pc, insn); /* MTZ */
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/* If this is a 32 bit instruction, we dont want to examine its
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immediate data as though it were an instruction */
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if (current_pc & 0x02)
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{ /* Clear the parallel execution bit from 16 bit instruction */
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if (maybe_one_more)
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{ /* The last instruction was a branch, usually terminates
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the series, but if this is a parallel instruction,
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it may be a stack framing instruction */
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if (!(insn & 0x8000))
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{
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insn_debug (("Really done"));
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break; /* nope, we are really done */
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}
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}
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insn &= 0x7fff; /* decode this instruction further */
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}
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else
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{
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if (maybe_one_more)
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break; /* This isnt the one more */
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if (insn & 0x8000)
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{
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insn_debug (("32 bit insn\n"));
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if (current_pc == scan_limit)
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scan_limit += 2; /* extend the search */
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current_pc += 2; /* skip the immediate data */
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if (insn == 0x8faf) /* add3 sp, sp, xxxx */
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/* add 16 bit sign-extended offset */
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{
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insn_debug (("stack increment\n"));
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framesize += -((short) read_memory_unsigned_integer (current_pc, 2));
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}
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else
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{
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if (((insn >> 8) == 0xe4) && /* ld24 r4, xxxxxx; sub sp, r4 */
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read_memory_unsigned_integer (current_pc + 2, 2) == 0x0f24)
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{ /* subtract 24 bit sign-extended negative-offset */
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dump_insn ("insn-2", current_pc + 2, insn);
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insn = read_memory_unsigned_integer (current_pc - 2, 4);
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dump_insn ("insn-3(l4)", current_pc - 2, insn);
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if (insn & 0x00800000) /* sign extend */
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insn |= 0xff000000; /* negative */
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else
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insn &= 0x00ffffff; /* positive */
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framesize += insn;
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}
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}
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after_prologue = current_pc;
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continue;
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}
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}
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op1 = insn & 0xf000; /* isolate just the first nibble */
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if ((insn & 0xf0ff) == 0x207f)
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{ /* st reg, @-sp */
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int regno;
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insn_debug (("push\n"));
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#if 0 /* No, PUSH FP is not an indication that we will use a frame pointer. */
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if (((insn & 0xffff) == 0x2d7f) && fi)
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fi->using_frame_pointer = 1;
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#endif
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framesize += 4;
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#if 0
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/* Why should we increase the scan limit, just because we did a push?
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And if there is a reason, surely we would only want to do it if we
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had already reached the scan limit... */
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if (current_pc == scan_limit)
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scan_limit += 2;
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#endif
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regno = ((insn >> 8) & 0xf);
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if (fsr) /* save_regs offset */
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fsr->regs[regno] = framesize;
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after_prologue = 0;
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continue;
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}
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if ((insn >> 8) == 0x4f) /* addi sp, xx */
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/* add 8 bit sign-extended offset */
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{
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int stack_adjust = (char) (insn & 0xff);
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/* there are probably two of these stack adjustments:
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1) A negative one in the prologue, and
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2) A positive one in the epilogue.
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We are only interested in the first one. */
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if (stack_adjust < 0)
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{
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framesize -= stack_adjust;
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after_prologue = 0;
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/* A frameless function may have no "mv fp, sp".
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In that case, this is the end of the prologue. */
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after_stack_adjust = current_pc + 2;
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}
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continue;
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}
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if (insn == 0x1d8f)
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{ /* mv fp, sp */
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if (fi)
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fi->using_frame_pointer = 1; /* fp is now valid */
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insn_debug (("done fp found\n"));
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after_prologue = current_pc + 2;
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break; /* end of stack adjustments */
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}
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if (insn == 0x7000) /* Nop looks like a branch, continue explicitly */
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{
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insn_debug (("nop\n"));
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after_prologue = current_pc + 2;
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continue; /* nop occurs between pushes */
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}
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/* End of prolog if any of these are branch instructions */
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if ((op1 == 0x7000)
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|| (op1 == 0xb000)
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|| (op1 == 0x7000))
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{
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after_prologue = current_pc;
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insn_debug (("Done: branch\n"));
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maybe_one_more = 1;
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continue;
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}
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/* Some of the branch instructions are mixed with other types */
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if (op1 == 0x1000)
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{
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int subop = insn & 0x0ff0;
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if ((subop == 0x0ec0) || (subop == 0x0fc0))
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{
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insn_debug (("done: jmp\n"));
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after_prologue = current_pc;
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maybe_one_more = 1;
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continue; /* jmp , jl */
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}
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}
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}
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if (current_pc >= scan_limit)
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{
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if (pl_endptr)
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{
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#if 1
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if (after_stack_adjust != 0)
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/* We did not find a "mv fp,sp", but we DID find
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a stack_adjust. Is it safe to use that as the
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end of the prologue? I just don't know. */
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{
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*pl_endptr = after_stack_adjust;
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if (framelength)
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*framelength = framesize;
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}
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else
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#endif
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/* We reached the end of the loop without finding the end
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of the prologue. No way to win -- we should report failure.
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The way we do that is to return the original start_pc.
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GDB will set a breakpoint at the start of the function (etc.) */
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*pl_endptr = start_pc;
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}
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return;
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}
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if (after_prologue == 0)
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after_prologue = current_pc;
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insn_debug ((" framesize %d, firstline %08x\n", framesize, after_prologue));
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if (framelength)
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*framelength = framesize;
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if (pl_endptr)
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*pl_endptr = after_prologue;
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} /* decode_prologue */
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/* Function: skip_prologue
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Find end of function prologue */
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CORE_ADDR
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m32r_skip_prologue (pc)
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CORE_ADDR pc;
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{
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CORE_ADDR func_addr, func_end;
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struct symtab_and_line sal;
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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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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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insn_debug (("BP after prologue %08x\n", sal.end));
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func_end = sal.end;
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}
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else
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/* Either there's no line info, or the line after the prologue is after
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the end of the function. In this case, there probably isn't a
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prologue. */
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{
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insn_debug (("No line info, line(%x) sal_end(%x) funcend(%x)\n",
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sal.line, sal.end, func_end));
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func_end = min (func_end, func_addr + DEFAULT_SEARCH_LIMIT);
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}
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}
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else
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func_end = pc + DEFAULT_SEARCH_LIMIT;
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decode_prologue (pc, func_end, &sal.end, 0, 0, 0);
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return sal.end;
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}
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static unsigned long
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m32r_scan_prologue (fi, fsr)
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struct frame_info *fi;
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struct frame_saved_regs *fsr;
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{
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struct symtab_and_line sal;
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CORE_ADDR prologue_start, prologue_end, current_pc;
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unsigned long framesize;
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/* this code essentially duplicates skip_prologue,
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but we need the start address below. */
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if (find_pc_partial_function (fi->pc, NULL, &prologue_start, &prologue_end))
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{
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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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if (prologue_start == entry_point_address ())
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return 0;
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}
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else
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{
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prologue_start = fi->pc;
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prologue_end = prologue_start + 48; /* We're in the boondocks:
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allow for 16 pushes, an add,
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and "mv fp,sp" */
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}
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#if 0
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prologue_end = min (prologue_end, fi->pc);
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#endif
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insn_debug (("fipc(%08x) start(%08x) end(%08x)\n",
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fi->pc, prologue_start, prologue_end));
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prologue_end = min (prologue_end, prologue_start + DEFAULT_SEARCH_LIMIT);
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decode_prologue (prologue_start, prologue_end, &prologue_end, &framesize,
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fi, fsr);
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return framesize;
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}
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/* Function: init_extra_frame_info
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This function actually figures out the frame address for a given pc and
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sp. This is tricky on the m32r because we sometimes don't use an explicit
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frame pointer, and the previous stack pointer isn't necessarily recorded
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on the stack. The only reliable way to get this info is to
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examine the prologue. */
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void
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m32r_init_extra_frame_info (fi)
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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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return;
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}
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else
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{
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fi->using_frame_pointer = 0;
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fi->framesize = m32r_scan_prologue (fi, &fi->fsr);
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if (!fi->next)
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if (fi->using_frame_pointer)
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{
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fi->frame = read_register (FP_REGNUM);
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}
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else
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fi->frame = read_register (SP_REGNUM);
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else
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/* fi->next means this is not the innermost frame */ if (fi->using_frame_pointer)
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/* we have an FP */
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if (fi->next->fsr.regs[FP_REGNUM] != 0) /* caller saved our FP */
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fi->frame = read_memory_integer (fi->next->fsr.regs[FP_REGNUM], 4);
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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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fi->fsr.regs[reg] = fi->frame + fi->framesize - fi->fsr.regs[reg];
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}
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}
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/* Function: mn10300_virtual_frame_pointer
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Return the register that the function uses for a frame pointer,
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plus any necessary offset to be applied to the register before
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any frame pointer offsets. */
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void
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m32r_virtual_frame_pointer (pc, reg, offset)
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CORE_ADDR pc;
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long *reg;
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long *offset;
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{
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struct frame_info fi;
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/* Set up a dummy frame_info. */
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fi.next = NULL;
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fi.prev = NULL;
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fi.frame = 0;
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fi.pc = pc;
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/* Analyze the prolog and fill in the extra info. */
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m32r_init_extra_frame_info (&fi);
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/* Results will tell us which type of frame it uses. */
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if (fi.using_frame_pointer)
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{
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*reg = FP_REGNUM;
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*offset = 0;
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}
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else
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{
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*reg = SP_REGNUM;
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*offset = 0;
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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. One thing
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we might want to do here is to check REGNUM against the clobber mask, and
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somehow flag it as invalid if it isn't saved on the stack somewhere. This
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would provide a graceful failure mode when trying to get the value of
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caller-saves registers for an inner frame. */
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CORE_ADDR
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m32r_find_callers_reg (fi, regnum)
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struct frame_info *fi;
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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))
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return generic_read_register_dummy (fi->pc, fi->frame, regnum);
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else if (fi->fsr.regs[regnum] != 0)
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return read_memory_integer (fi->fsr.regs[regnum],
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REGISTER_RAW_SIZE (regnum));
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return read_register (regnum);
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}
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/* Function: frame_chain
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Given a GDB frame, determine the address of the calling function's frame.
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This will be used to create a new GDB frame struct, and then
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INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC will be called for the new frame.
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For m32r, we save the frame size when we initialize the frame_info. */
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CORE_ADDR
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m32r_frame_chain (fi)
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struct frame_info *fi;
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{
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CORE_ADDR fn_start, callers_pc, fp;
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|
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/* is this a dummy frame? */
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if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame))
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return fi->frame; /* dummy frame same as caller's frame */
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|
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/* is caller-of-this a dummy frame? */
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|
callers_pc = FRAME_SAVED_PC (fi); /* find out who called us: */
|
|
fp = m32r_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 */
|
|
if (fi->framesize == 0)
|
|
{
|
|
printf_filtered ("cannot determine frame size @ %s , pc(%s)\n",
|
|
paddr (fi->frame),
|
|
paddr (fi->pc));
|
|
return 0;
|
|
}
|
|
insn_debug (("m32rx frame %08x\n", fi->frame + fi->framesize));
|
|
return fi->frame + fi->framesize;
|
|
}
|
|
|
|
/* Function: push_return_address (pc)
|
|
Set up the return address for the inferior function call.
|
|
Necessary for targets that don't actually execute a JSR/BSR instruction
|
|
(ie. when using an empty CALL_DUMMY) */
|
|
|
|
CORE_ADDR
|
|
m32r_push_return_address (pc, sp)
|
|
CORE_ADDR pc;
|
|
CORE_ADDR sp;
|
|
{
|
|
write_register (RP_REGNUM, CALL_DUMMY_ADDRESS ());
|
|
return sp;
|
|
}
|
|
|
|
|
|
/* Function: pop_frame
|
|
Discard from the stack the innermost frame,
|
|
restoring all saved registers. */
|
|
|
|
struct frame_info *
|
|
m32r_pop_frame (frame)
|
|
struct frame_info *frame;
|
|
{
|
|
int regnum;
|
|
|
|
if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame))
|
|
generic_pop_dummy_frame ();
|
|
else
|
|
{
|
|
for (regnum = 0; regnum < NUM_REGS; regnum++)
|
|
if (frame->fsr.regs[regnum] != 0)
|
|
write_register (regnum,
|
|
read_memory_integer (frame->fsr.regs[regnum], 4));
|
|
|
|
write_register (PC_REGNUM, FRAME_SAVED_PC (frame));
|
|
write_register (SP_REGNUM, read_register (FP_REGNUM));
|
|
if (read_register (PSW_REGNUM) & 0x80)
|
|
write_register (SPU_REGNUM, read_register (SP_REGNUM));
|
|
else
|
|
write_register (SPI_REGNUM, read_register (SP_REGNUM));
|
|
}
|
|
flush_cached_frames ();
|
|
return NULL;
|
|
}
|
|
|
|
/* 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. */
|
|
|
|
CORE_ADDR
|
|
m32r_frame_saved_pc (fi)
|
|
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 m32r_find_callers_reg (fi, RP_REGNUM);
|
|
}
|
|
|
|
/* Function: push_arguments
|
|
Setup the function arguments for calling a function in the inferior.
|
|
|
|
On the Mitsubishi M32R architecture, there are four registers (R0 to R3)
|
|
which are dedicated for passing function arguments. Up to the first
|
|
four arguments (depending on size) may go into these registers.
|
|
The rest go on the stack.
|
|
|
|
Arguments that are smaller than 4 bytes will still take up a whole
|
|
register or a whole 32-bit word on the stack, and will be
|
|
right-justified in the register or the stack word. This includes
|
|
chars, shorts, and small aggregate types.
|
|
|
|
Arguments of 8 bytes size are split between two registers, if
|
|
available. If only one register is available, the argument will
|
|
be split between the register and the stack. Otherwise it is
|
|
passed entirely on the stack. Aggregate types with sizes between
|
|
4 and 8 bytes are passed entirely on the stack, and are left-justified
|
|
within the double-word (as opposed to aggregates smaller than 4 bytes
|
|
which are right-justified).
|
|
|
|
Aggregates of greater than 8 bytes are first copied onto the stack,
|
|
and then a pointer to the copy is passed in the place of the normal
|
|
argument (either in a register if available, or on the stack).
|
|
|
|
Functions that must return an aggregate type can return it in the
|
|
normal return value registers (R0 and R1) if its size is 8 bytes or
|
|
less. For larger return values, the caller must allocate space for
|
|
the callee to copy the return value to. A pointer to this space is
|
|
passed as an implicit first argument, always in R0. */
|
|
|
|
CORE_ADDR
|
|
m32r_push_arguments (nargs, args, sp, struct_return, struct_addr)
|
|
int nargs;
|
|
value_ptr *args;
|
|
CORE_ADDR sp;
|
|
unsigned char struct_return;
|
|
CORE_ADDR struct_addr;
|
|
{
|
|
int stack_offset, stack_alloc;
|
|
int argreg;
|
|
int argnum;
|
|
struct type *type;
|
|
CORE_ADDR regval;
|
|
char *val;
|
|
char valbuf[4];
|
|
int len;
|
|
int odd_sized_struct;
|
|
|
|
/* first force sp to a 4-byte alignment */
|
|
sp = sp & ~3;
|
|
|
|
argreg = ARG0_REGNUM;
|
|
/* The "struct return pointer" pseudo-argument goes in R0 */
|
|
if (struct_return)
|
|
write_register (argreg++, struct_addr);
|
|
|
|
/* Now make sure there's space on the stack */
|
|
for (argnum = 0, stack_alloc = 0;
|
|
argnum < nargs; argnum++)
|
|
stack_alloc += ((TYPE_LENGTH (VALUE_TYPE (args[argnum])) + 3) & ~3);
|
|
sp -= stack_alloc; /* make room on stack for args */
|
|
|
|
|
|
/* Now load as many as possible of the first arguments into
|
|
registers, and push the rest onto the stack. There are 16 bytes
|
|
in four registers available. Loop thru args from first to last. */
|
|
|
|
argreg = ARG0_REGNUM;
|
|
for (argnum = 0, stack_offset = 0; argnum < nargs; argnum++)
|
|
{
|
|
type = VALUE_TYPE (args[argnum]);
|
|
len = TYPE_LENGTH (type);
|
|
memset (valbuf, 0, sizeof (valbuf));
|
|
if (len < 4)
|
|
{ /* value gets right-justified in the register or stack word */
|
|
memcpy (valbuf + (4 - len),
|
|
(char *) VALUE_CONTENTS (args[argnum]), len);
|
|
val = valbuf;
|
|
}
|
|
else
|
|
val = (char *) VALUE_CONTENTS (args[argnum]);
|
|
|
|
if (len > 4 && (len & 3) != 0)
|
|
odd_sized_struct = 1; /* such structs go entirely on stack */
|
|
else
|
|
odd_sized_struct = 0;
|
|
while (len > 0)
|
|
{
|
|
if (argreg > ARGLAST_REGNUM || odd_sized_struct)
|
|
{ /* must go on the stack */
|
|
write_memory (sp + stack_offset, val, 4);
|
|
stack_offset += 4;
|
|
}
|
|
/* NOTE WELL!!!!! This is not an "else if" clause!!!
|
|
That's because some *&^%$ things get passed on the stack
|
|
AND in the registers! */
|
|
if (argreg <= ARGLAST_REGNUM)
|
|
{ /* there's room in a register */
|
|
regval = extract_address (val, REGISTER_RAW_SIZE (argreg));
|
|
write_register (argreg++, regval);
|
|
}
|
|
/* Store the value 4 bytes at a time. This means that things
|
|
larger than 4 bytes may go partly in registers and partly
|
|
on the stack. */
|
|
len -= REGISTER_RAW_SIZE (argreg);
|
|
val += REGISTER_RAW_SIZE (argreg);
|
|
}
|
|
}
|
|
return sp;
|
|
}
|
|
|
|
/* Function: fix_call_dummy
|
|
If there is real CALL_DUMMY code (eg. on the stack), this function
|
|
has the responsability to insert the address of the actual code that
|
|
is the target of the target function call. */
|
|
|
|
void
|
|
m32r_fix_call_dummy (dummy, pc, fun, nargs, args, type, gcc_p)
|
|
char *dummy;
|
|
CORE_ADDR pc;
|
|
CORE_ADDR fun;
|
|
int nargs;
|
|
value_ptr *args;
|
|
struct type *type;
|
|
int gcc_p;
|
|
{
|
|
/* ld24 r8, <(imm24) fun> */
|
|
*(unsigned long *) (dummy) = (fun & 0x00ffffff) | 0xe8000000;
|
|
}
|
|
|
|
|
|
/* Function: m32r_write_sp
|
|
Because SP is really a read-only register that mirrors either SPU or SPI,
|
|
we must actually write one of those two as well, depending on PSW. */
|
|
|
|
void
|
|
m32r_write_sp (val)
|
|
CORE_ADDR val;
|
|
{
|
|
unsigned long psw = read_register (PSW_REGNUM);
|
|
|
|
if (psw & 0x80) /* stack mode: user or interrupt */
|
|
write_register (SPU_REGNUM, val);
|
|
else
|
|
write_register (SPI_REGNUM, val);
|
|
write_register (SP_REGNUM, val);
|
|
}
|
|
|
|
void
|
|
_initialize_m32r_tdep ()
|
|
{
|
|
tm_print_insn = print_insn_m32r;
|
|
}
|