binutils-gdb/gdb/i387-nat.c

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/* Native-dependent code for the i387.
Copyright 2000, 2001 Free Software Foundation, Inc.
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This file is part of GDB.
This program 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 2 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "defs.h"
#include "inferior.h"
#include "value.h"
#include "regcache.h"
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#include "i387-nat.h"
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/* FIXME: kettenis/2000-05-21: Right now more than a few i386 targets
define their own routines to manage the floating-point registers in
GDB's register array. Most (if not all) of these targets use the
format used by the "fsave" instruction in their communication with
the OS. They should all be converted to use the routines below. */
/* At fsave_offset[REGNUM] you'll find the offset to the location in
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the data structure used by the "fsave" instruction where GDB
register REGNUM is stored. */
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static int fsave_offset[] =
{
28 + 0 * FPU_REG_RAW_SIZE, /* FP0_REGNUM through ... */
28 + 1 * FPU_REG_RAW_SIZE,
28 + 2 * FPU_REG_RAW_SIZE,
28 + 3 * FPU_REG_RAW_SIZE,
28 + 4 * FPU_REG_RAW_SIZE,
28 + 5 * FPU_REG_RAW_SIZE,
28 + 6 * FPU_REG_RAW_SIZE,
28 + 7 * FPU_REG_RAW_SIZE, /* ... FP7_REGNUM. */
0, /* FCTRL_REGNUM (16 bits). */
4, /* FSTAT_REGNUM (16 bits). */
8, /* FTAG_REGNUM (16 bits). */
16, /* FCS_REGNUM (16 bits). */
12, /* FCOFF_REGNUM. */
24, /* FDS_REGNUM. */
20, /* FDOFF_REGNUM. */
18 /* FOP_REGNUM (bottom 11 bits). */
};
#define FSAVE_ADDR(fsave, regnum) (fsave + fsave_offset[regnum - FP0_REGNUM])
/* Fill register REGNUM in GDB's register array with the appropriate
value from *FSAVE. This function masks off any of the reserved
bits in *FSAVE. */
void
i387_supply_register (int regnum, char *fsave)
{
/* Most of the FPU control registers occupy only 16 bits in
the fsave area. Give those a special treatment. */
if (regnum >= FIRST_FPU_CTRL_REGNUM
&& regnum != FCOFF_REGNUM && regnum != FDOFF_REGNUM)
{
unsigned int val = *(unsigned short *) (FSAVE_ADDR (fsave, regnum));
if (regnum == FOP_REGNUM)
{
val &= ((1 << 11) - 1);
supply_register (regnum, (char *) &val);
}
else
supply_register (regnum, (char *) &val);
}
else
supply_register (regnum, FSAVE_ADDR (fsave, regnum));
}
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/* Fill GDB's register array with the floating-point register values
in *FSAVE. This function masks off any of the reserved
bits in *FSAVE. */
void
i387_supply_fsave (char *fsave)
{
int i;
for (i = FP0_REGNUM; i <= LAST_FPU_CTRL_REGNUM; i++)
i387_supply_register (i, fsave);
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}
/* Fill register REGNUM (if it is a floating-point register) in *FSAVE
with the value in GDB's register array. If REGNUM is -1, do this
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for all registers. This function doesn't touch any of the reserved
bits in *FSAVE. */
void
i387_fill_fsave (char *fsave, int regnum)
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{
int i;
for (i = FP0_REGNUM; i <= LAST_FPU_CTRL_REGNUM; i++)
if (regnum == -1 || regnum == i)
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{
/* Most of the FPU control registers occupy only 16 bits in
the fsave area. Give those a special treatment. */
if (i >= FIRST_FPU_CTRL_REGNUM
&& i != FCOFF_REGNUM && i != FDOFF_REGNUM)
{
if (i == FOP_REGNUM)
{
unsigned short oldval, newval;
/* The opcode occupies only 11 bits. */
oldval = (*(unsigned short *) (FSAVE_ADDR (fsave, i)));
newval = *(unsigned short *) &registers[REGISTER_BYTE (i)];
newval &= ((1 << 11) - 1);
newval |= oldval & ~((1 << 11) - 1);
memcpy (FSAVE_ADDR (fsave, i), &newval, 2);
}
else
memcpy (FSAVE_ADDR (fsave, i), &registers[REGISTER_BYTE (i)], 2);
}
else
memcpy (FSAVE_ADDR (fsave, i), &registers[REGISTER_BYTE (i)],
REGISTER_RAW_SIZE (i));
}
}
/* At fxsave_offset[REGNUM] you'll find the offset to the location in
the data structure used by the "fxsave" instruction where GDB
register REGNUM is stored. */
static int fxsave_offset[] =
{
32, /* FP0_REGNUM through ... */
48,
64,
80,
96,
112,
128,
144, /* ... FP7_REGNUM (80 bits each). */
0, /* FCTRL_REGNUM (16 bits). */
2, /* FSTAT_REGNUM (16 bits). */
4, /* FTAG_REGNUM (16 bits). */
12, /* FCS_REGNUM (16 bits). */
8, /* FCOFF_REGNUM. */
20, /* FDS_REGNUM (16 bits). */
16, /* FDOFF_REGNUM. */
6, /* FOP_REGNUM (bottom 11 bits). */
160, /* XMM0_REGNUM through ... */
176,
192,
208,
224,
240,
256,
272, /* ... XMM7_REGNUM (128 bits each). */
24, /* MXCSR_REGNUM. */
};
#define FXSAVE_ADDR(fxsave, regnum) \
(fxsave + fxsave_offset[regnum - FP0_REGNUM])
static int i387_tag (unsigned char *raw);
/* Fill GDB's register array with the floating-point and SSE register
values in *FXSAVE. This function masks off any of the reserved
bits in *FXSAVE. */
void
i387_supply_fxsave (char *fxsave)
{
int i;
for (i = FP0_REGNUM; i <= MXCSR_REGNUM; i++)
{
/* Most of the FPU control registers occupy only 16 bits in
the fxsave area. Give those a special treatment. */
if (i >= FIRST_FPU_CTRL_REGNUM && i < XMM0_REGNUM
&& i != FCOFF_REGNUM && i != FDOFF_REGNUM)
{
unsigned long val = *(unsigned short *) (FXSAVE_ADDR (fxsave, i));
if (i == FOP_REGNUM)
{
val &= ((1 << 11) - 1);
supply_register (i, (char *) &val);
}
else if (i== FTAG_REGNUM)
{
/* The fxsave area contains a simplified version of the
tag word. We have to look at the actual 80-bit FP
data to recreate the traditional i387 tag word. */
unsigned long ftag = 0;
unsigned long fstat;
int fpreg;
int top;
fstat = *(unsigned short *) (FXSAVE_ADDR (fxsave, FSTAT_REGNUM));
top = ((fstat >> 11) & 0x7);
for (fpreg = 7; fpreg >= 0; fpreg--)
{
int tag;
if (val & (1 << fpreg))
{
int regnum = (fpreg + 8 - top) % 8 + FP0_REGNUM;
tag = i387_tag (FXSAVE_ADDR (fxsave, regnum));
}
else
tag = 3; /* Empty */
ftag |= tag << (2 * fpreg);
}
supply_register (i, (char *) &ftag);
}
else
supply_register (i, (char *) &val);
}
else
supply_register (i, FXSAVE_ADDR (fxsave, i));
}
}
/* Fill register REGNUM (if it is a floating-point or SSE register) in
*FXSAVE with the value in GDB's register array. If REGNUM is -1, do
this for all registers. This function doesn't touch any of the
reserved bits in *FXSAVE. */
void
i387_fill_fxsave (char *fxsave, int regnum)
{
int i;
for (i = FP0_REGNUM; i <= MXCSR_REGNUM; i++)
if (regnum == -1 || regnum == i)
{
/* Most of the FPU control registers occupy only 16 bits in
the fxsave area. Give those a special treatment. */
if (i >= FIRST_FPU_CTRL_REGNUM && i < XMM0_REGNUM
&& i != FCOFF_REGNUM && i != FDOFF_REGNUM)
{
if (i == FOP_REGNUM)
{
unsigned short oldval, newval;
/* The opcode occupies only 11 bits. */
oldval = (*(unsigned short *) (FXSAVE_ADDR (fxsave, i)));
newval = *(unsigned short *) &registers[REGISTER_BYTE (i)];
newval &= ((1 << 11) - 1);
newval |= oldval & ~((1 << 11) - 1);
memcpy (FXSAVE_ADDR (fxsave, i), &newval, 2);
}
else if (i == FTAG_REGNUM)
{
/* Converting back is much easier. */
unsigned char val = 0;
unsigned short ftag;
int fpreg;
ftag = *(unsigned short *) &registers[REGISTER_BYTE (i)];
for (fpreg = 7; fpreg >= 0; fpreg--)
{
int tag = (ftag >> (fpreg * 2)) & 3;
if (tag != 3)
val |= (1 << (fpreg * 2));
}
memcpy (FXSAVE_ADDR (fxsave, i), &val, 2);
}
else
memcpy (FXSAVE_ADDR (fxsave, i),
&registers[REGISTER_BYTE (i)], 2);
}
else
memcpy (FXSAVE_ADDR (fxsave, i), &registers[REGISTER_BYTE (i)],
REGISTER_RAW_SIZE (i));
}
}
/* Recreate the FTW (tag word) valid bits from the 80-bit FP data in
*RAW. */
static int
i387_tag (unsigned char *raw)
{
int integer;
unsigned int exponent;
unsigned long fraction[2];
integer = raw[7] & 0x80;
exponent = (((raw[9] & 0x7f) << 8) | raw[8]);
fraction[0] = ((raw[3] << 24) | (raw[2] << 16) | (raw[1] << 8) | raw[0]);
fraction[1] = (((raw[7] & 0x7f) << 24) | (raw[6] << 16)
| (raw[5] << 8) | raw[4]);
if (exponent == 0x7fff)
{
/* Special. */
return (2);
}
else if (exponent == 0x0000)
{
if (fraction[0] == 0x0000 && fraction[1] == 0x0000 && !integer)
{
/* Zero. */
return (1);
}
else
{
/* Special. */
return (2);
}
}
else
{
if (integer)
{
/* Valid. */
return (0);
}
else
{
/* Special. */
return (2);
}
}
}