394 lines
10 KiB
C
394 lines
10 KiB
C
/* Target dependent code for the Motorola 68000 series.
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Copyright (C) 1990, 1992 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "defs.h"
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#include "ieee-float.h"
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#include "frame.h"
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#include "symtab.h"
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const struct ext_format ext_format_68881 = {
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/* tot sbyte smask expbyte manbyte */
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12, 0, 0x80, 0,1, 4,8 /* mc68881 */
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};
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/* Things needed for making the inferior call functions.
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It seems like every m68k based machine has almost identical definitions
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in the individual machine's configuration files. Most other cpu types
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(mips, i386, etc) have routines in their *-tdep.c files to handle this
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for most configurations. The m68k family should be able to do this as
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well. These macros can still be overridden when necessary. */
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/* Push an empty stack frame, to record the current PC, etc. */
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void
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m68k_push_dummy_frame ()
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{
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register CORE_ADDR sp = read_register (SP_REGNUM);
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register int regnum;
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char raw_buffer[12];
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sp = push_word (sp, read_register (PC_REGNUM));
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sp = push_word (sp, read_register (FP_REGNUM));
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write_register (FP_REGNUM, sp);
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#if defined (HAVE_68881)
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for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--)
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{
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read_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12);
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sp = push_bytes (sp, raw_buffer, 12);
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}
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#endif
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for (regnum = FP_REGNUM - 1; regnum >= 0; regnum--)
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{
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sp = push_word (sp, read_register (regnum));
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}
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sp = push_word (sp, read_register (PS_REGNUM));
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write_register (SP_REGNUM, sp);
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}
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/* Discard from the stack the innermost frame,
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restoring all saved registers. */
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void
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m68k_pop_frame ()
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{
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register FRAME frame = get_current_frame ();
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register CORE_ADDR fp;
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register int regnum;
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struct frame_saved_regs fsr;
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struct frame_info *fi;
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char raw_buffer[12];
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fi = get_frame_info (frame);
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fp = fi -> frame;
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get_frame_saved_regs (fi, &fsr);
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#if defined (HAVE_68881)
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for (regnum = FP0_REGNUM + 7 ; regnum >= FP0_REGNUM ; regnum--)
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{
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if (fsr.regs[regnum])
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{
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read_memory (fsr.regs[regnum], raw_buffer, 12);
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write_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12);
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}
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}
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#endif
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for (regnum = FP_REGNUM - 1 ; regnum >= 0 ; regnum--)
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{
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if (fsr.regs[regnum])
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{
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write_register (regnum, read_memory_integer (fsr.regs[regnum], 4));
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}
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}
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if (fsr.regs[PS_REGNUM])
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{
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write_register (PS_REGNUM, read_memory_integer (fsr.regs[PS_REGNUM], 4));
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}
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write_register (FP_REGNUM, read_memory_integer (fp, 4));
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write_register (PC_REGNUM, read_memory_integer (fp + 4, 4));
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write_register (SP_REGNUM, fp + 8);
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flush_cached_frames ();
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set_current_frame (create_new_frame (read_register (FP_REGNUM),
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read_pc ()));
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}
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/* Given an ip value corresponding to the start of a function,
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return the ip of the first instruction after the function
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prologue. This is the generic m68k support. Machines which
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require something different can override the SKIP_PROLOGUE
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macro to point elsewhere.
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Some instructions which typically may appear in a function
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prologue include:
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A link instruction, word form:
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link.w %a6,&0 4e56 XXXX
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A link instruction, long form:
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link.l %fp,&F%1 480e XXXX XXXX
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A movm instruction to preserve integer regs:
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movm.l &M%1,(4,%sp) 48ef XXXX XXXX
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A fmovm instruction to preserve float regs:
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fmovm &FPM%1,(FPO%1,%sp) f237 XXXX XXXX XXXX XXXX
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Some profiling setup code (FIXME, not recognized yet):
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lea.l (.L3,%pc),%a1 43fb XXXX XXXX XXXX
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bsr _mcount 61ff XXXX XXXX
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*/
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#define P_LINK_L 0x480e
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#define P_LINK_W 0x4e56
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#define P_MOV_L 0x207c
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#define P_JSR 0x4eb9
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#define P_BSR 0x61ff
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#define P_LEA_L 0x43fb
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#define P_MOVM_L 0x48ef
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#define P_FMOVM 0xf237
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#define P_TRAP 0x4e40
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CORE_ADDR
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m68k_skip_prologue (ip)
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CORE_ADDR ip;
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{
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register CORE_ADDR limit;
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struct symtab_and_line sal;
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register int op;
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/* Find out if there is a known limit for the extent of the prologue.
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If so, ensure we don't go past it. If not, assume "infinity". */
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sal = find_pc_line (ip, 0);
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limit = (sal.end) ? sal.end : (CORE_ADDR) ~0;
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while (ip < limit)
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{
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op = read_memory_integer (ip, 2);
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op &= 0xFFFF;
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if (op == P_LINK_W)
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{
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ip += 4; /* Skip link.w */
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}
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else if (op == P_LINK_L)
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{
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ip += 6; /* Skip link.l */
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}
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else if (op == P_MOVM_L)
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{
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ip += 6; /* Skip movm.l */
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}
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else if (op == P_FMOVM)
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{
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ip += 10; /* Skip fmovm */
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}
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else
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{
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break; /* Found unknown code, bail out. */
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}
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}
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return (ip);
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}
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#ifdef USE_PROC_FS /* Target dependent support for /proc */
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#include <sys/procfs.h>
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/* The /proc interface divides the target machine's register set up into
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two different sets, the general register set (gregset) and the floating
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point register set (fpregset). For each set, there is an ioctl to get
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the current register set and another ioctl to set the current values.
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The actual structure passed through the ioctl interface is, of course,
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naturally machine dependent, and is different for each set of registers.
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For the m68k for example, the general register set is typically defined
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by:
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typedef int gregset_t[18];
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#define R_D0 0
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...
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#define R_PS 17
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and the floating point set by:
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typedef struct fpregset {
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int f_pcr;
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int f_psr;
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int f_fpiaddr;
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int f_fpregs[8][3]; (8 regs, 96 bits each)
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} fpregset_t;
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These routines provide the packing and unpacking of gregset_t and
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fpregset_t formatted data.
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*/
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/* Given a pointer to a general register set in /proc format (gregset_t *),
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unpack the register contents and supply them as gdb's idea of the current
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register values. */
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void
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supply_gregset (gregsetp)
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gregset_t *gregsetp;
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{
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register int regi;
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register greg_t *regp = (greg_t *) gregsetp;
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for (regi = 0 ; regi < R_PC ; regi++)
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{
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supply_register (regi, (char *) (regp + regi));
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}
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supply_register (PS_REGNUM, (char *) (regp + R_PS));
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supply_register (PC_REGNUM, (char *) (regp + R_PC));
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}
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void
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fill_gregset (gregsetp, regno)
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gregset_t *gregsetp;
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int regno;
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{
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register int regi;
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register greg_t *regp = (greg_t *) gregsetp;
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extern char registers[];
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for (regi = 0 ; regi < R_PC ; regi++)
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{
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if ((regno == -1) || (regno == regi))
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{
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*(regp + regi) = *(int *) ®isters[REGISTER_BYTE (regi)];
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}
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}
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if ((regno == -1) || (regno == PS_REGNUM))
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{
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*(regp + R_PS) = *(int *) ®isters[REGISTER_BYTE (PS_REGNUM)];
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}
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if ((regno == -1) || (regno == PC_REGNUM))
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{
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*(regp + R_PC) = *(int *) ®isters[REGISTER_BYTE (PC_REGNUM)];
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}
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}
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#if defined (FP0_REGNUM)
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/* Given a pointer to a floating point register set in /proc format
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(fpregset_t *), unpack the register contents and supply them as gdb's
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idea of the current floating point register values. */
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void
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supply_fpregset (fpregsetp)
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fpregset_t *fpregsetp;
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{
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register int regi;
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char *from;
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for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++)
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{
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from = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]);
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supply_register (regi, from);
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}
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supply_register (FPC_REGNUM, (char *) &(fpregsetp -> f_pcr));
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supply_register (FPS_REGNUM, (char *) &(fpregsetp -> f_psr));
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supply_register (FPI_REGNUM, (char *) &(fpregsetp -> f_fpiaddr));
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}
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/* Given a pointer to a floating point register set in /proc format
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(fpregset_t *), update the register specified by REGNO from gdb's idea
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of the current floating point register set. If REGNO is -1, update
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them all. */
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void
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fill_fpregset (fpregsetp, regno)
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fpregset_t *fpregsetp;
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int regno;
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{
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int regi;
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char *to;
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char *from;
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extern char registers[];
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for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++)
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{
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if ((regno == -1) || (regno == regi))
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{
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from = (char *) ®isters[REGISTER_BYTE (regi)];
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to = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]);
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bcopy (from, to, REGISTER_RAW_SIZE (regi));
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}
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}
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if ((regno == -1) || (regno == FPC_REGNUM))
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{
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fpregsetp -> f_pcr = *(int *) ®isters[REGISTER_BYTE (FPC_REGNUM)];
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}
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if ((regno == -1) || (regno == FPS_REGNUM))
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{
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fpregsetp -> f_psr = *(int *) ®isters[REGISTER_BYTE (FPS_REGNUM)];
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}
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if ((regno == -1) || (regno == FPI_REGNUM))
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{
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fpregsetp -> f_fpiaddr = *(int *) ®isters[REGISTER_BYTE (FPI_REGNUM)];
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}
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}
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#endif /* defined (FP0_REGNUM) */
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#endif /* USE_PROC_FS */
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#ifdef GET_LONGJMP_TARGET
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/* Figure out where the longjmp will land. Slurp the args out of the stack.
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We expect the first arg to be a pointer to the jmp_buf structure from which
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we extract the pc (JB_PC) that we will land at. The pc is copied into PC.
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This routine returns true on success. */
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int
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get_longjmp_target(pc)
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CORE_ADDR *pc;
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{
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CORE_ADDR sp, jb_addr;
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sp = read_register(SP_REGNUM);
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if (target_read_memory(sp + SP_ARG0, /* Offset of first arg on stack */
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&jb_addr,
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sizeof(CORE_ADDR)))
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return 0;
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SWAP_TARGET_AND_HOST(&jb_addr, sizeof(CORE_ADDR));
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if (target_read_memory(jb_addr + JB_PC * JB_ELEMENT_SIZE, pc,
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sizeof(CORE_ADDR)))
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return 0;
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SWAP_TARGET_AND_HOST(pc, sizeof(CORE_ADDR));
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return 1;
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}
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#endif /* GET_LONGJMP_TARGET */
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/* Immediately after a function call, return the saved pc before the frame
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is setup. We check for the common case of being inside of a system call,
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and if so, we know that Sun pushes the call # on the stack prior to doing
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the trap. */
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CORE_ADDR
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m68k_saved_pc_after_call(frame)
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struct frame_info *frame;
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{
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#ifdef sun
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int op;
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op = read_memory_integer (frame->pc, 2);
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op &= 0xFFFF;
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if (op == P_TRAP)
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return read_memory_integer (read_register (SP_REGNUM) + 4, 4);
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else
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#endif /* sun */
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return read_memory_integer (read_register (SP_REGNUM), 4);
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}
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