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binutils-gdb/gdb/i386-xdep.c

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Johns release
1991-03-29 00:28:29 +08:00
/* Intel 386 stuff.
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 <stdio.h>
#include "defs.h"
#include "param.h"
#include "frame.h"
#include "inferior.h"
#include "gdbcore.h"
#ifdef USG
#include <sys/types.h>
#endif
#include <sys/param.h>
#include <sys/dir.h>
#include <signal.h>
#include <sys/user.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/reg.h>
/* this table must line up with REGISTER_NAMES in m-i386.h */
/* symbols like 'EAX' come from <sys/reg.h> */
static int regmap[] =
{
EAX, ECX, EDX, EBX,
UESP, EBP, ESI, EDI,
EIP, EFL, CS, SS,
DS, ES, FS, GS,
};
/* blockend is the value of u.u_ar0, and points to the
* place where GS is stored
*/
i386_register_u_addr (blockend, regnum)
{
#if 0
/* this will be needed if fp registers are reinstated */
/* for now, you can look at them with 'info float'
* sys5 wont let you change them with ptrace anyway
*/
if (regnum >= FP0_REGNUM && regnum <= FP7_REGNUM)
{
int ubase, fpstate;
struct user u;
ubase = blockend + 4 * (SS + 1) - KSTKSZ;
fpstate = ubase + ((char *)&u.u_fpstate - (char *)&u);
return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
}
else
#endif
return (blockend + 4 * regmap[regnum]);
}
/* This is broken for cross debugging. Possible solutions are:
1. Don't worry about whether the thing compiles for cross-debugging.
Go ahead and call them from i386-tdep.c.
1a. Same thing but use some macros in xm-i386.h so that gdb will
compile for cross-debugging but just give an error (or some such behavior)
when you attempt to convert floats.
2. Write a portable (in the sense of running on any machine; it would
always be for i387 floating-point formats) extended<->double converter
(which just deals with the values as arrays of char).
3. Assume the host machine has *some* IEEE chip. However, IEEE does
not standardize formats for extended floats (387 is 10 bytes, 68881 is
12 bytes), so this won't work. */
i387_to_double (from, to)
char *from;
char *to;
{
long *lp;
/* push extended mode on 387 stack, then pop in double mode
*
* first, set exception masks so no error is generated -
* number will be rounded to inf or 0, if necessary
*/
asm ("pushl %eax"); /* grab a stack slot */
asm ("fstcw (%esp)"); /* get 387 control word */
asm ("movl (%esp),%eax"); /* save old value */
asm ("orl $0x3f,%eax"); /* mask all exceptions */
asm ("pushl %eax");
asm ("fldcw (%esp)"); /* load new value into 387 */
asm ("movl 8(%ebp),%eax");
asm ("fldt (%eax)"); /* push extended number on 387 stack */
asm ("fwait");
asm ("movl 12(%ebp),%eax");
asm ("fstpl (%eax)"); /* pop double */
asm ("fwait");
asm ("popl %eax"); /* flush modified control word */
asm ("fnclex"); /* clear exceptions */
asm ("fldcw (%esp)"); /* restore original control word */
asm ("popl %eax"); /* flush saved copy */
}
double_to_i387 (from, to)
char *from;
char *to;
{
/* push double mode on 387 stack, then pop in extended mode
* no errors are possible because every 64-bit pattern
* can be converted to an extended
*/
asm ("movl 8(%ebp),%eax");
asm ("fldl (%eax)");
asm ("fwait");
asm ("movl 12(%ebp),%eax");
asm ("fstpt (%eax)");
asm ("fwait");
}
struct env387
{
unsigned short control;
unsigned short r0;
unsigned short status;
unsigned short r1;
unsigned short tag;
unsigned short r2;
unsigned long eip;
unsigned short code_seg;
unsigned short opcode;
unsigned long operand;
unsigned short operand_seg;
unsigned short r3;
unsigned char regs[8][10];
};
static
print_387_control_word (control)
unsigned short control;
{
printf ("control 0x%04x: ", control);
printf ("compute to ");
switch ((control >> 8) & 3)
{
case 0: printf ("24 bits; "); break;
case 1: printf ("(bad); "); break;
case 2: printf ("53 bits; "); break;
case 3: printf ("64 bits; "); break;
}
printf ("round ");
switch ((control >> 10) & 3)
{
case 0: printf ("NEAREST; "); break;
case 1: printf ("DOWN; "); break;
case 2: printf ("UP; "); break;
case 3: printf ("CHOP; "); break;
}
if (control & 0x3f)
{
printf ("mask:");
if (control & 0x0001) printf (" INVALID");
if (control & 0x0002) printf (" DENORM");
if (control & 0x0004) printf (" DIVZ");
if (control & 0x0008) printf (" OVERF");
if (control & 0x0010) printf (" UNDERF");
if (control & 0x0020) printf (" LOS");
printf (";");
}
printf ("\n");
if (control & 0xe080) printf ("warning: reserved bits on 0x%x\n",
control & 0xe080);
}
static
print_387_status_word (status)
unsigned short status;
{
printf ("status 0x%04x: ", status);
if (status & 0xff)
{
printf ("exceptions:");
if (status & 0x0001) printf (" INVALID");
if (status & 0x0002) printf (" DENORM");
if (status & 0x0004) printf (" DIVZ");
if (status & 0x0008) printf (" OVERF");
if (status & 0x0010) printf (" UNDERF");
if (status & 0x0020) printf (" LOS");
if (status & 0x0040) printf (" FPSTACK");
printf ("; ");
}
printf ("flags: %d%d%d%d; ",
(status & 0x4000) != 0,
(status & 0x0400) != 0,
(status & 0x0200) != 0,
(status & 0x0100) != 0);
printf ("top %d\n", (status >> 11) & 7);
}
static
print_387_status (status, ep)
unsigned short status;
struct env387 *ep;
{
int i;
int bothstatus;
int top;
int fpreg;
unsigned char *p;
bothstatus = ((status != 0) && (ep->status != 0));
if (status != 0)
{
if (bothstatus)
printf ("u: ");
print_387_status_word (status);
}
if (ep->status != 0)
{
if (bothstatus)
printf ("e: ");
print_387_status_word (ep->status);
}
print_387_control_word (ep->control);
printf ("last exception: ");
printf ("opcode 0x%x; ", ep->opcode);
printf ("pc 0x%x:0x%x; ", ep->code_seg, ep->eip);
printf ("operand 0x%x:0x%x\n", ep->operand_seg, ep->operand);
top = (ep->status >> 11) & 7;
printf ("regno tag msb lsb value\n");
for (fpreg = 7; fpreg >= 0; fpreg--)
{
double val;
printf ("%s %d: ", fpreg == top ? "=>" : " ", fpreg);
switch ((ep->tag >> (fpreg * 2)) & 3)
{
case 0: printf ("valid "); break;
case 1: printf ("zero "); break;
case 2: printf ("trap "); break;
case 3: printf ("empty "); break;
}
for (i = 9; i >= 0; i--)
printf ("%02x", ep->regs[fpreg][i]);
i387_to_double (ep->regs[fpreg], (char *)&val);
printf (" %g\n", val);
}
if (ep->r0)
printf ("warning: reserved0 is 0x%x\n", ep->r0);
if (ep->r1)
printf ("warning: reserved1 is 0x%x\n", ep->r1);
if (ep->r2)
printf ("warning: reserved2 is 0x%x\n", ep->r2);
if (ep->r3)
printf ("warning: reserved3 is 0x%x\n", ep->r3);
}
#ifndef U_FPSTATE
#define U_FPSTATE(u) u.u_fpstate
#endif
i386_float_info ()
{
struct user u; /* just for address computations */
int i;
/* fpstate defined in <sys/user.h> */
struct fpstate *fpstatep;
char buf[sizeof (struct fpstate) + 2 * sizeof (int)];
unsigned int uaddr;
char fpvalid;
unsigned int rounded_addr;
unsigned int rounded_size;
extern int corechan;
int skip;
uaddr = (char *)&u.u_fpvalid - (char *)&u;
if (have_inferior_p())
{
unsigned int data;
unsigned int mask;
rounded_addr = uaddr & -sizeof (int);
data = ptrace (3, inferior_pid, rounded_addr, 0);
mask = 0xff << ((uaddr - rounded_addr) * 8);
fpvalid = ((data & mask) != 0);
}
else
{
if (lseek (corechan, uaddr, 0) < 0)
perror ("seek on core file");
if (myread (corechan, &fpvalid, 1) < 0)
perror ("read on core file");
}
if (fpvalid == 0)
{
printf ("no floating point status saved\n");
return;
}
uaddr = (char *)&U_FPSTATE(u) - (char *)&u;
if (have_inferior_p ())
{
int *ip;
rounded_addr = uaddr & -sizeof (int);
rounded_size = (((uaddr + sizeof (struct fpstate)) - uaddr) +
sizeof (int) - 1) / sizeof (int);
skip = uaddr - rounded_addr;
ip = (int *)buf;
for (i = 0; i < rounded_size; i++)
{
*ip++ = ptrace (3, inferior_pid, rounded_addr, 0);
rounded_addr += sizeof (int);
}
}
else
{
if (lseek (corechan, uaddr, 0) < 0)
perror_with_name ("seek on core file");
if (myread (corechan, buf, sizeof (struct fpstate)) < 0)
perror_with_name ("read from core file");
skip = 0;
}
fpstatep = (struct fpstate *)(buf + skip);
print_387_status (fpstatep->status, (struct env387 *)fpstatep->state);
}
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