binutils-gdb/gdb/arm-tdep.c

/* Copyright (C) 1988, 1989 Free Software Foundation, Inc.

This file is part of GDB.

GDB is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.

GDB is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GDB; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "defs.h"
#include "param.h"
#include "frame.h"
#include "inferior.h"
#include "arm-opcode.h"

#include <stdio.h>
#include <sys/param.h>
#include <sys/dir.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/ptrace.h>
#include <machine/reg.h>

#define N_TXTADDR(hdr) 0x8000
#define N_DATADDR(hdr) (hdr.a_text + 0x8000)

#include "gdbcore.h"
#include <sys/user.h>		/* After a.out.h  */
#include <sys/file.h>
#include <sys/stat.h>

#include <errno.h>


/* Work with core dump and executable files, for GDB. 
   This code would be in core.c if it weren't machine-dependent. */

/* Structure to describe the chain of shared libraries used
   by the execfile.
   e.g. prog shares Xt which shares X11 which shares c. */

struct shared_library {
    struct exec_header header;
    char name[SHLIBLEN];
    CORE_ADDR text_start;	/* CORE_ADDR of 1st byte of text, this file */
    long data_offset;		/* offset of data section in file */
    int chan;			/* file descriptor for the file */
    struct shared_library *shares; /* library this one shares */
};
static struct shared_library *shlib = 0;

/* Hook for `exec_file_command' command to call.  */

extern void (*exec_file_display_hook) ();
   
static CORE_ADDR unshared_text_start;

/* extended header from exec file (for shared library info) */

static struct exec_header exec_header;

void
exec_file_command (filename, from_tty)
     char *filename;
     int from_tty;
{
  int val;

  /* Eliminate all traces of old exec file.
     Mark text segment as empty.  */

  if (execfile)
    free (execfile);
  execfile = 0;
  data_start = 0;
  data_end -= exec_data_start;
  text_start = 0;
  unshared_text_start = 0;
  text_end = 0;
  exec_data_start = 0;
  exec_data_end = 0;
  if (execchan >= 0)
    close (execchan);
  execchan = -1;
  if (shlib) {
      close_shared_library(shlib);
      shlib = 0;
  }

  /* Now open and digest the file the user requested, if any.  */

  if (filename)
    {
      filename = tilde_expand (filename);
      make_cleanup (free, filename);

      execchan = openp (getenv ("PATH"), 1, filename, O_RDONLY, 0,
			&execfile);
      if (execchan < 0)
	perror_with_name (filename);

      {
	struct stat st_exec;

#ifdef HEADER_SEEK_FD
	HEADER_SEEK_FD (execchan);
#endif
	
	val = myread (execchan, &exec_header, sizeof exec_header);
	exec_aouthdr = exec_header.a_exec;

	if (val < 0)
	  perror_with_name (filename);

	text_start = 0x8000;

	/* Look for shared library if needed */
	if (exec_header.a_exec.a_magic & MF_USES_SL)
	    shlib = open_shared_library(exec_header.a_shlibname, text_start);

	text_offset = N_TXTOFF (exec_aouthdr);
	exec_data_offset = N_TXTOFF (exec_aouthdr) + exec_aouthdr.a_text;

	if (shlib) {
	    unshared_text_start = shared_text_end(shlib) & ~0x7fff;
	    stack_start = shlib->header.a_exec.a_sldatabase;
	    stack_end = STACK_END_ADDR;
	} else
	    unshared_text_start = 0x8000;
	text_end = unshared_text_start + exec_aouthdr.a_text;

	exec_data_start = unshared_text_start + exec_aouthdr.a_text;
        exec_data_end = exec_data_start + exec_aouthdr.a_data;

	data_start = exec_data_start;
	data_end += exec_data_start;

	fstat (execchan, &st_exec);
	exec_mtime = st_exec.st_mtime;
      }

      validate_files ();
    }
  else if (from_tty)
    printf ("No exec file now.\n");

  /* Tell display code (if any) about the changed file name.  */
  if (exec_file_display_hook)
    (*exec_file_display_hook) (filename);
}

/* Read from the program's memory (except for inferior processes).
   This function is misnamed, since it only reads, never writes; and
   since it will use the core file and/or executable file as necessary.

   It should be extended to write as well as read, FIXME, for patching files.

   Return 0 if address could be read, EIO if addresss out of bounds.  */

int
xfer_core_file (memaddr, myaddr, len)
     CORE_ADDR memaddr;
     char *myaddr;
     int len;
{
  register int i;
  register int val;
  int xferchan;
  char **xferfile;
  int fileptr;
  int returnval = 0;

  while (len > 0)
    {
      xferfile = 0;
      xferchan = 0;

      /* Determine which file the next bunch of addresses reside in,
	 and where in the file.  Set the file's read/write pointer
	 to point at the proper place for the desired address
	 and set xferfile and xferchan for the correct file.

	 If desired address is nonexistent, leave them zero.

	 i is set to the number of bytes that can be handled
	 along with the next address.

	 We put the most likely tests first for efficiency.  */

      /* Note that if there is no core file
	 data_start and data_end are equal.  */
      if (memaddr >= data_start && memaddr < data_end)
	{
	  i = min (len, data_end - memaddr);
	  fileptr = memaddr - data_start + data_offset;
	  xferfile = &corefile;
	  xferchan = corechan;
	}
      /* Note that if there is no core file
	 stack_start and stack_end define the shared library data.  */
      else if (memaddr >= stack_start && memaddr < stack_end)
	{
	    if (corechan < 0) {
		struct shared_library *lib;
		for (lib = shlib; lib; lib = lib->shares)
		    if (memaddr >= lib->header.a_exec.a_sldatabase &&
			memaddr < lib->header.a_exec.a_sldatabase +
			  lib->header.a_exec.a_data)
			break;
		if (lib) {
		    i = min (len, lib->header.a_exec.a_sldatabase +
			     lib->header.a_exec.a_data - memaddr);
		    fileptr = lib->data_offset + memaddr -
			lib->header.a_exec.a_sldatabase;
		    xferfile = execfile;
		    xferchan = lib->chan;
		}
	    } else {
		i = min (len, stack_end - memaddr);
		fileptr = memaddr - stack_start + stack_offset;
		xferfile = &corefile;
		xferchan = corechan;
	    }
	}
      else if (corechan < 0
	       && memaddr >= exec_data_start && memaddr < exec_data_end)
	{
	  i = min (len, exec_data_end - memaddr);
	  fileptr = memaddr - exec_data_start + exec_data_offset;
	  xferfile = &execfile;
	  xferchan = execchan;
	}
      else if (memaddr >= text_start && memaddr < text_end)
	{
	    struct shared_library *lib;
	    for (lib = shlib; lib; lib = lib->shares)
		if (memaddr >= lib->text_start &&
		    memaddr < lib->text_start + lib->header.a_exec.a_text)
		    break;
	    if (lib) {
		i = min (len, lib->header.a_exec.a_text +
			 lib->text_start - memaddr);
		fileptr = memaddr - lib->text_start + text_offset;
		xferfile = &execfile;
		xferchan = lib->chan;
	    } else {
		i = min (len, text_end - memaddr);
		fileptr = memaddr - unshared_text_start + text_offset;
		xferfile = &execfile;
		xferchan = execchan;
	    }
	}
      else if (memaddr < text_start)
	{
	  i = min (len, text_start - memaddr);
	}
      else if (memaddr >= text_end
	       && memaddr < (corechan >= 0? data_start : exec_data_start))
	{
	  i = min (len, data_start - memaddr);
	}
      else if (corechan >= 0
	       && memaddr >= data_end && memaddr < stack_start)
	{
	  i = min (len, stack_start - memaddr);
	}
      else if (corechan < 0 && memaddr >= exec_data_end)
	{
	  i = min (len, - memaddr);
	}
      else if (memaddr >= stack_end && stack_end != 0)
	{
	  i = min (len, - memaddr);
	}
      else
	{
	  /* Address did not classify into one of the known ranges.
	     This shouldn't happen; we catch the endpoints.  */
	  fatal ("Internal: Bad case logic in xfer_core_file.");
	}

      /* Now we know which file to use.
	 Set up its pointer and transfer the data.  */
      if (xferfile)
	{
	  if (*xferfile == 0)
	    if (xferfile == &execfile)
	      error ("No program file to examine.");
	    else
	      error ("No core dump file or running program to examine.");
	  val = lseek (xferchan, fileptr, 0);
	  if (val < 0)
	    perror_with_name (*xferfile);
	  val = myread (xferchan, myaddr, i);
	  if (val < 0)
	    perror_with_name (*xferfile);
	}
      /* If this address is for nonexistent memory,
	 read zeros if reading, or do nothing if writing.
	 Actually, we never right.  */
      else
	{
	  bzero (myaddr, i);
	  returnval = EIO;
	}

      memaddr += i;
      myaddr += i;
      len -= i;
    }
  return returnval;
}

/* APCS (ARM procedure call standard) defines the following prologue:

   mov		ip, sp
  [stmfd	sp!, {a1,a2,a3,a4}]
   stmfd	sp!, {...,fp,ip,lr,pc}
  [stfe		f7, [sp, #-12]!]
  [stfe		f6, [sp, #-12]!]
  [stfe		f5, [sp, #-12]!]
  [stfe		f4, [sp, #-12]!]
   sub		fp, ip, #nn	// nn == 20 or 4 depending on second ins
*/

CORE_ADDR
skip_prologue(pc)
CORE_ADDR pc;
{
    union insn_fmt op;
    CORE_ADDR skip_pc = pc;

    op.ins = read_memory_integer(skip_pc, 4);
    /* look for the "mov ip,sp" */
    if (op.generic.type != TYPE_ARITHMETIC ||
	op.arith.opcode != OPCODE_MOV ||
	op.arith.dest != SPTEMP ||
	op.arith.operand2 != SP) return pc;
    skip_pc += 4;
    /* skip the "stmfd sp!,{a1,a2,a3,a4}" if its there */
    op.ins = read_memory_integer(skip_pc, 4);
    if (op.generic.type == TYPE_BLOCK_BRANCH &&
	op.generic.subtype == SUBTYPE_BLOCK &&
	op.block.mask == 0xf &&
	op.block.base == SP &&
	op.block.is_load == 0 &&
	op.block.writeback == 1 &&
	op.block.increment == 0 &&
	op.block.before == 1) skip_pc += 4;
    /* skip the "stmfd sp!,{...,fp,ip,lr,pc} */
    op.ins = read_memory_integer(skip_pc, 4);
    if (op.generic.type != TYPE_BLOCK_BRANCH ||
	op.generic.subtype != SUBTYPE_BLOCK ||
	/* the mask should look like 110110xxxxxx0000 */
	(op.block.mask & 0xd800) != 0xd800 ||
	op.block.base != SP ||
	op.block.is_load != 0 ||
	op.block.writeback != 1 ||
	op.block.increment != 0 ||
	op.block.before != 1) return pc;
    skip_pc += 4;
    /* check for "sub fp,ip,#nn" */
    op.ins = read_memory_integer(skip_pc, 4);
    if (op.generic.type != TYPE_ARITHMETIC ||
	op.arith.opcode != OPCODE_SUB ||
	op.arith.dest != FP ||
	op.arith.operand1 != SPTEMP) return pc;
    return skip_pc + 4;
}

static void
print_fpu_flags(flags)
int flags;
{
    if (flags & (1 << 0)) fputs("IVO ", stdout);
    if (flags & (1 << 1)) fputs("DVZ ", stdout);
    if (flags & (1 << 2)) fputs("OFL ", stdout);
    if (flags & (1 << 3)) fputs("UFL ", stdout);
    if (flags & (1 << 4)) fputs("INX ", stdout);
    putchar('\n');
}

void
arm_float_info()
{
    register unsigned long status = read_register(FPS_REGNUM);
    int type;

    type = (status >> 24) & 127;
    printf("%s FPU type %d\n",
	   (status & (1<<31)) ? "Hardware" : "Software",
	   type);
    fputs("mask: ", stdout);
    print_fpu_flags(status >> 16);
    fputs("flags: ", stdout);
    print_fpu_flags(status);
}