binutils-gdb/gdb/symm-tdep.c

/* Sequent Symmetry target interface, for GDB when running under Unix.
   Copyright (C) 1986, 1987, 1989, 1991 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.  */

/* many 387-specific items of use taken from i386-dep.c */

#include <stdio.h>
#include "defs.h"
#include "param.h"
#include "frame.h"
#include "inferior.h"
#include "symtab.h"

#include <signal.h>
#include <sys/param.h>
#include <sys/user.h>
#include <sys/dir.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include "gdbcore.h"
#include <fcntl.h>

static long i386_get_frame_setup ();
static i386_follow_jump ();

#include <sgtty.h>
#define TERMINAL struct sgttyb

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;
  text_end = 0;
  exec_data_start = 0;
  exec_data_end = 0;
  if (execchan >= 0)
    close (execchan);
  execchan = -1;

  /* 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);

#ifdef COFF_FORMAT
      {
	int aout_hdrsize;
	int num_sections;

	if (read_file_hdr (execchan, &file_hdr) < 0)
	  error ("\"%s\": not in executable format.", execfile);

	aout_hdrsize = file_hdr.f_opthdr;
	num_sections = file_hdr.f_nscns;

	if (read_aout_hdr (execchan, &exec_aouthdr, aout_hdrsize) < 0)
	  error ("\"%s\": can't read optional aouthdr", execfile);

	if (read_section_hdr (execchan, _TEXT, &text_hdr, num_sections,
			      aout_hdrsize) < 0)
	  error ("\"%s\": can't read text section header", execfile);

	if (read_section_hdr (execchan, _DATA, &data_hdr, num_sections,
			      aout_hdrsize) < 0)
	  error ("\"%s\": can't read data section header", execfile);

	text_start = exec_aouthdr.text_start;
	text_end = text_start + exec_aouthdr.tsize;
	text_offset = text_hdr.s_scnptr;
	exec_data_start = exec_aouthdr.data_start;
	exec_data_end = exec_data_start + exec_aouthdr.dsize;
	exec_data_offset = data_hdr.s_scnptr;
	data_start = exec_data_start;
	data_end += exec_data_start;
	exec_mtime = file_hdr.f_timdat;
      }
#else /* not COFF_FORMAT */
      {
	struct stat st_exec;

	val = myread (execchan, &exec_aouthdr, sizeof (AOUTHDR));

	if (val < 0)
	  perror_with_name (filename);

	text_start = N_ADDRADJ(exec_aouthdr);
        exec_data_start = round(exec_aouthdr.a_text, NBPG*CLSIZE);
	text_offset = N_TXTOFF (exec_aouthdr);
	exec_data_offset = N_TXTOFF (exec_aouthdr) + exec_aouthdr.a_text;
	text_end = exec_aouthdr.a_text;
        exec_data_end = exec_data_start + exec_aouthdr.a_data;
	data_start = exec_data_start;
	data_end = data_start + exec_aouthdr.a_data;
	exec_data_offset = N_TXTOFF(exec_aouthdr);
	fstat (execchan, &st_exec);
	exec_mtime = st_exec.st_mtime;
      }
#endif /* not COFF_FORMAT */

      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);
}

/* rounds 'one' up to divide evenly by 'two' */

int
round(one,two)
register int one, two;

{
    register int temp;
    temp = (one/two)*two;
    if (one != temp) {
	temp += two;
    }
    return temp;
}


static CORE_ADDR codestream_next_addr;
static CORE_ADDR codestream_addr;
static unsigned char codestream_buf[sizeof (int)];
static int codestream_off;
static int codestream_cnt;

#define codestream_tell() (codestream_addr + codestream_off)
#define codestream_peek() (codestream_cnt == 0 ? \
			   codestream_fill(1): codestream_buf[codestream_off])
#define codestream_get() (codestream_cnt-- == 0 ? \
			 codestream_fill(0) : codestream_buf[codestream_off++])


static unsigned char 
codestream_fill (peek_flag)
{
  codestream_addr = codestream_next_addr;
  codestream_next_addr += sizeof (int);
  codestream_off = 0;
  codestream_cnt = sizeof (int);
  read_memory (codestream_addr,
	       (unsigned char *)codestream_buf,
	       sizeof (int));
  
  if (peek_flag)
    return (codestream_peek());
  else
    return (codestream_get());
}

static void
codestream_seek (place)
{
  codestream_next_addr = place & -sizeof (int);
  codestream_cnt = 0;
  codestream_fill (1);
  while (codestream_tell() != place)
    codestream_get ();
}

static void
codestream_read (buf, count)
     unsigned char *buf;
{
  unsigned char *p;
  int i;
  p = buf;
  for (i = 0; i < count; i++)
    *p++ = codestream_get ();
}

/*
 * Following macro translates i386 opcode register numbers to Symmetry
 * register numbers.  This is used by FRAME_FIND_SAVED_REGS.
 *
 *           %eax  %ecx  %edx  %ebx  %esp  %ebp  %esi  %edi
 * i386        0     1     2     3     4     5     6     7
 * Symmetry    0     2     1     5    14    15     6     7
 *
 */
#define I386_REGNO_TO_SYMMETRY(n) \
((n)==0?0 :(n)==1?2 :(n)==2?1 :(n)==3?5 :(n)==4?14 :(n)==5?15 :(n))

/* from i386-dep.c */
i386_frame_find_saved_regs (fip, fsrp)
     struct frame_info *fip;
     struct frame_saved_regs *fsrp;
{
  unsigned long locals;
  unsigned char *p;
  unsigned char op;
  CORE_ADDR dummy_bottom;
  CORE_ADDR adr;
  int i;
  
  bzero (fsrp, sizeof *fsrp);
  
  /* if frame is the end of a dummy, compute where the
   * beginning would be
   */
  dummy_bottom = fip->frame - 4 - NUM_REGS*4 - CALL_DUMMY_LENGTH;
  
  /* check if the PC is in the stack, in a dummy frame */
  if (dummy_bottom <= fip->pc && fip->pc <= fip->frame) 
    {
      /* all regs were saved by push_call_dummy () */
      adr = fip->frame - 4;
      for (i = 0; i < NUM_REGS; i++) 
	{
	  fsrp->regs[i] = adr;
	  adr -= 4;
	}
      return;
    }
  
  locals = i386_get_frame_setup (get_pc_function_start (fip->pc));
  
  if (locals >= 0) 
    {
      adr = fip->frame - 4 - locals;
      for (i = 0; i < 8; i++) 
	{
	  op = codestream_get ();
	  if (op < 0x50 || op > 0x57)
	    break;
	  fsrp->regs[I386_REGNO_TO_SYMMETRY(op - 0x50)] = adr;
	  adr -= 4;
	}
    }
  
  fsrp->regs[PC_REGNUM] = fip->frame + 4;
  fsrp->regs[FP_REGNUM] = fip->frame;
}

static long
i386_get_frame_setup (pc)
{
  unsigned char op;
  
  codestream_seek (pc);
  
  i386_follow_jump ();
  
  op = codestream_get ();
  
  if (op == 0x58) /* popl %eax */
    {
      /*
       * this function must start with
       * 
       *    popl %eax		  0x58
       *    xchgl %eax, (%esp)  0x87 0x04 0x24
       * or xchgl %eax, 0(%esp) 0x87 0x44 0x24 0x00
       *
       * (the system 5 compiler puts out the second xchg
       * inst, and the assembler doesn't try to optimize it,
       * so the 'sib' form gets generated)
       * 
       * this sequence is used to get the address of the return
       * buffer for a function that returns a structure
       */
      int pos;
      unsigned char buf[4];
      static unsigned char proto1[3] = { 0x87,0x04,0x24 };
      static unsigned char proto2[4] = { 0x87,0x44,0x24,0x00 };
      pos = codestream_tell ();
      codestream_read (buf, 4);
      if (bcmp (buf, proto1, 3) == 0)
	pos += 3;
      else if (bcmp (buf, proto2, 4) == 0)
	pos += 4;
      
      codestream_seek (pos);
      op = codestream_get (); /* update next opcode */
    }
  
  if (op == 0x55) 			/* pushl %esp */
    {
      if (codestream_get () != 0x8b)	/* movl %esp, %ebp (2bytes) */
	return (-1);
      if (codestream_get () != 0xec)
	return (-1);
      /*
       * check for stack adjustment 
       *
       *  subl $XXX, %esp
       *
       * note: you can't subtract a 16 bit immediate
       * from a 32 bit reg, so we don't have to worry
       * about a data16 prefix 
       */
      op = codestream_peek ();
      if (op == 0x83)  /* subl with 8 bit immed */
	{
	  codestream_get ();
	  if (codestream_get () != 0xec)
	    return (-1);
	  /* subl with signed byte immediate 
	   * (though it wouldn't make sense to be negative)
	   */
	  return (codestream_get());
	}
      else if (op == 0x81)  /* subl with 32 bit immed */
	{
	  int locals;
	  if (codestream_get () != 0xec)
	    return (-1);
	  /* subl with 32 bit immediate */
	  codestream_read ((unsigned char *)&locals, 4);
	  return (locals);
	} 
      else 
	{
	  return (0);
	}
    } 
  else if (op == 0xc8) 
    {
      /* enter instruction: arg is 16 unsigned immed */
      unsigned short slocals;
      codestream_read ((unsigned char *)&slocals, 2);
      codestream_get (); /* flush final byte of enter instruction */
      return (slocals);
    }
  return (-1);
}

/* next instruction is a jump, move to target */
static
i386_follow_jump ()
{
  int long_delta;
  short short_delta;
  char byte_delta;
  int data16;
  int pos;
  
  pos = codestream_tell ();
  
  data16 = 0;
  if (codestream_peek () == 0x66)
    {
      codestream_get ();
      data16 = 1;
    }
  
  switch (codestream_get ())
    {
    case 0xe9:
      /* relative jump: if data16 == 0, disp32, else disp16 */
      if (data16)
	{
	  codestream_read ((unsigned char *)&short_delta, 2);
	  pos += short_delta + 3; /* include size of jmp inst */
	}
      else
	{
	  codestream_read ((unsigned char *)&long_delta, 4);
	  pos += long_delta + 5;
	}
      break;
    case 0xeb:
      /* relative jump, disp8 (ignore data16) */
      codestream_read ((unsigned char *)&byte_delta, 1);
      pos += byte_delta + 2;
      break;
    }
  codestream_seek (pos + data16);
}

/* return pc of first real instruction */
/* from i386-dep.c */

i386_skip_prologue (pc)
{
  unsigned char op;
  int i;
  
  if (i386_get_frame_setup (pc) < 0)
    return (pc);
  
  /* found valid frame setup - codestream now points to 
   * start of push instructions for saving registers
   */
  
  /* skip over register saves */
  for (i = 0; i < 8; i++)
    {
      op = codestream_peek ();
      /* break if not pushl inst */
      if (op < 0x50 || op > 0x57) 
	break;
      codestream_get ();
    }
  
  i386_follow_jump ();
  
  return (codestream_tell ());
}

symmetry_extract_return_value(type, regbuf, valbuf)
     struct type *type;
     char *regbuf;
     char *valbuf;
{
  union { 
    double	d; 
    int	l[2]; 
  } xd; 
  int i;
  float f;

  if (TYPE_CODE_FLT == TYPE_CODE(type)) { 
    for (i = 0; i < misc_function_count; i++) {
      if (!strcmp(misc_function_vector[i].name, "1167_flt"))
	break;
    }
    if (i < misc_function_count) {
      /* found "1167_flt" means 1167, %fp2-%fp3 */ 
      /* float & double; 19= %fp2, 20= %fp3 */
      /* no single precision on 1167 */
      xd.l[1] = *((int *)&regbuf[REGISTER_BYTE(19)]);
      xd.l[0] = *((int *)&regbuf[REGISTER_BYTE(20)]);
      switch (TYPE_LENGTH(type)) {
      case 4:
	f = (float) xd.d;
	bcopy(&f, valbuf, TYPE_LENGTH(type));
	break;
      case 8:
	bcopy(&xd.d, valbuf, TYPE_LENGTH(type)); 
	break;
      default:
	error("Unknown floating point size");
	break;
      }
    } else { 
      /* 387 %st(0), gcc uses this */ 
      i387_to_double(((int *)&regbuf[REGISTER_BYTE(3)]),
		     &xd.d); 
      switch (TYPE_LENGTH(type)) {
      case 4:			/* float */
	f = (float) xd.d;
	bcopy(&f, valbuf, 4); 
	break;
      case 8:			/* double */
	bcopy(&xd.d, valbuf, 8);
	break;
      default:
	error("Unknown floating point size");
	break;
      }
    }
  } else { 
    bcopy (regbuf, valbuf, TYPE_LENGTH (type)); 
  }
}