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406 lines
11 KiB
C
406 lines
11 KiB
C
/* Intel 387 floating point stuff.
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Copyright 1988, 1989, 1991, 1992, 1993, 1994, 1998, 1999, 2000, 2001
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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., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "frame.h"
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#include "inferior.h"
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#include "language.h"
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#include "value.h"
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#include "gdbcore.h"
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#include "floatformat.h"
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#include "regcache.h"
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#include "gdb_assert.h"
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#include "doublest.h"
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#if GDB_MULTI_ARCH >0
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#include "i386-tdep.h"
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#endif
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/* FIXME: Eliminate the next two functions when we have the time to
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change all the callers. */
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void i387_to_double (char *from, char *to);
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void double_to_i387 (char *from, char *to);
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void
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i387_to_double (char *from, char *to)
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{
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floatformat_to_double (&floatformat_i387_ext, from, (double *) to);
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}
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void
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double_to_i387 (char *from, char *to)
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{
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floatformat_from_double (&floatformat_i387_ext, (double *) from, to);
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}
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/* FIXME: The functions on this page are used by the old `info float'
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implementations that a few of the i386 targets provide. These
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functions should be removed if all of these have been converted to
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use the generic implementation based on the new register file
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layout. */
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static void print_387_control_bits (unsigned int control);
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static void print_387_status_bits (unsigned int status);
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static void
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print_387_control_bits (unsigned int control)
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{
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switch ((control >> 8) & 3)
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{
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case 0:
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puts_unfiltered (" 24 bit; ");
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break;
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case 1:
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puts_unfiltered (" (bad); ");
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break;
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case 2:
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puts_unfiltered (" 53 bit; ");
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break;
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case 3:
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puts_unfiltered (" 64 bit; ");
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break;
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}
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switch ((control >> 10) & 3)
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{
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case 0:
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puts_unfiltered ("NEAR; ");
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break;
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case 1:
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puts_unfiltered ("DOWN; ");
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break;
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case 2:
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puts_unfiltered ("UP; ");
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break;
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case 3:
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puts_unfiltered ("CHOP; ");
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break;
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}
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if (control & 0x3f)
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{
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puts_unfiltered ("mask");
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if (control & 0x0001)
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puts_unfiltered (" INVAL");
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if (control & 0x0002)
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puts_unfiltered (" DENOR");
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if (control & 0x0004)
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puts_unfiltered (" DIVZ");
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if (control & 0x0008)
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puts_unfiltered (" OVERF");
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if (control & 0x0010)
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puts_unfiltered (" UNDER");
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if (control & 0x0020)
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puts_unfiltered (" LOS");
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puts_unfiltered (";");
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}
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if (control & 0xe080)
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warning ("\nreserved bits on: %s",
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local_hex_string (control & 0xe080));
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}
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void
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print_387_control_word (unsigned int control)
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{
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printf_filtered ("control %s:", local_hex_string(control & 0xffff));
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print_387_control_bits (control);
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puts_unfiltered ("\n");
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}
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static void
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print_387_status_bits (unsigned int status)
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{
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printf_unfiltered (" flags %d%d%d%d; ",
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(status & 0x4000) != 0,
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(status & 0x0400) != 0,
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(status & 0x0200) != 0,
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(status & 0x0100) != 0);
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printf_unfiltered ("top %d; ", (status >> 11) & 7);
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if (status & 0xff)
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{
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puts_unfiltered ("excep");
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if (status & 0x0001) puts_unfiltered (" INVAL");
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if (status & 0x0002) puts_unfiltered (" DENOR");
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if (status & 0x0004) puts_unfiltered (" DIVZ");
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if (status & 0x0008) puts_unfiltered (" OVERF");
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if (status & 0x0010) puts_unfiltered (" UNDER");
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if (status & 0x0020) puts_unfiltered (" LOS");
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if (status & 0x0040) puts_unfiltered (" STACK");
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}
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}
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void
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print_387_status_word (unsigned int status)
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{
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printf_filtered ("status %s:", local_hex_string (status & 0xffff));
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print_387_status_bits (status);
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puts_unfiltered ("\n");
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}
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/* Implement the `info float' layout based on the register definitions
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in `tm-i386.h'. */
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/* Print the floating point number specified by RAW. */
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static void
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print_i387_value (char *raw)
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{
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DOUBLEST value;
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int len = TARGET_LONG_DOUBLE_BIT / TARGET_CHAR_BIT;
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char *tmp = alloca (len);
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/* This code only works on targets where ... */
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gdb_assert (TARGET_LONG_DOUBLE_FORMAT == &floatformat_i387_ext);
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/* Take care of the padding. FP reg is 80 bits. The same value in
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memory is 96 bits. */
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gdb_assert (FPU_REG_RAW_SIZE < len);
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memcpy (tmp, raw, FPU_REG_RAW_SIZE);
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memset (tmp + FPU_REG_RAW_SIZE, 0, len - FPU_REG_RAW_SIZE);
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/* Extract the value as a DOUBLEST. */
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/* Use extract_floating() rather than floatformat_to_doublest().
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The latter is lossy in nature. Once GDB gets a host/target
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independent and non-lossy FP it will become possible to bypass
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extract_floating() and call floatformat*() directly. Note also
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the assumptions about TARGET_LONG_DOUBLE above. */
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value = extract_floating (tmp, len);
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/* We try to print 19 digits. The last digit may or may not contain
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garbage, but we'd better print one too many. We need enough room
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to print the value, 1 position for the sign, 1 for the decimal
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point, 19 for the digits and 6 for the exponent adds up to 27. */
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#ifdef PRINTF_HAS_LONG_DOUBLE
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printf_filtered (" %-+27.19Lg", (long double) value);
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#else
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printf_filtered (" %-+27.19g", (double) value);
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#endif
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}
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/* Print the classification for the register contents RAW. */
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static void
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print_i387_ext (unsigned char *raw)
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{
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int sign;
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int integer;
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unsigned int exponent;
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unsigned long fraction[2];
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sign = raw[9] & 0x80;
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integer = raw[7] & 0x80;
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exponent = (((raw[9] & 0x7f) << 8) | raw[8]);
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fraction[0] = ((raw[3] << 24) | (raw[2] << 16) | (raw[1] << 8) | raw[0]);
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fraction[1] = (((raw[7] & 0x7f) << 24) | (raw[6] << 16)
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| (raw[5] << 8) | raw[4]);
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if (exponent == 0x7fff && integer)
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{
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if (fraction[0] == 0x00000000 && fraction[1] == 0x00000000)
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/* Infinity. */
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printf_filtered (" %cInf", (sign ? '-' : '+'));
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else if (sign && fraction[0] == 0x00000000 && fraction[1] == 0x40000000)
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/* Real Indefinite (QNaN). */
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puts_unfiltered (" Real Indefinite (QNaN)");
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else if (fraction[1] & 0x40000000)
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/* QNaN. */
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puts_filtered (" QNaN");
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else
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/* SNaN. */
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puts_filtered (" SNaN");
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}
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else if (exponent < 0x7fff && exponent > 0x0000 && integer)
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/* Normal. */
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print_i387_value (raw);
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else if (exponent == 0x0000)
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{
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/* Denormal or zero. */
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print_i387_value (raw);
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if (integer)
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/* Pseudo-denormal. */
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puts_filtered (" Pseudo-denormal");
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else if (fraction[0] || fraction[1])
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/* Denormal. */
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puts_filtered (" Denormal");
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}
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else
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/* Unsupported. */
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puts_filtered (" Unsupported");
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}
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/* Print the status word STATUS. */
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static void
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print_i387_status_word (unsigned int status)
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{
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printf_filtered ("Status Word: %s",
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local_hex_string_custom (status, "04"));
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puts_filtered (" ");
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printf_filtered (" %s", (status & 0x0001) ? "IE" : " ");
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printf_filtered (" %s", (status & 0x0002) ? "DE" : " ");
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printf_filtered (" %s", (status & 0x0004) ? "ZE" : " ");
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printf_filtered (" %s", (status & 0x0008) ? "OE" : " ");
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printf_filtered (" %s", (status & 0x0010) ? "UE" : " ");
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printf_filtered (" %s", (status & 0x0020) ? "PE" : " ");
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puts_filtered (" ");
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printf_filtered (" %s", (status & 0x0080) ? "ES" : " ");
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puts_filtered (" ");
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printf_filtered (" %s", (status & 0x0040) ? "SF" : " ");
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puts_filtered (" ");
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printf_filtered (" %s", (status & 0x0100) ? "C0" : " ");
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printf_filtered (" %s", (status & 0x0200) ? "C1" : " ");
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printf_filtered (" %s", (status & 0x0400) ? "C2" : " ");
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printf_filtered (" %s", (status & 0x4000) ? "C3" : " ");
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puts_filtered ("\n");
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printf_filtered (" TOP: %d\n", ((status >> 11) & 7));
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}
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/* Print the control word CONTROL. */
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static void
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print_i387_control_word (unsigned int control)
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{
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printf_filtered ("Control Word: %s",
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local_hex_string_custom (control, "04"));
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puts_filtered (" ");
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printf_filtered (" %s", (control & 0x0001) ? "IM" : " ");
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printf_filtered (" %s", (control & 0x0002) ? "DM" : " ");
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printf_filtered (" %s", (control & 0x0004) ? "ZM" : " ");
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printf_filtered (" %s", (control & 0x0008) ? "OM" : " ");
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printf_filtered (" %s", (control & 0x0010) ? "UM" : " ");
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printf_filtered (" %s", (control & 0x0020) ? "PM" : " ");
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puts_filtered ("\n");
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puts_filtered (" PC: ");
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switch ((control >> 8) & 3)
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{
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case 0:
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puts_filtered ("Single Precision (24-bits)\n");
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break;
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case 1:
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puts_filtered ("Reserved\n");
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break;
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case 2:
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puts_filtered ("Double Precision (53-bits)\n");
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break;
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case 3:
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puts_filtered ("Extended Precision (64-bits)\n");
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break;
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}
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puts_filtered (" RC: ");
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switch ((control >> 10) & 3)
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{
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case 0:
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puts_filtered ("Round to nearest\n");
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break;
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case 1:
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puts_filtered ("Round down\n");
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break;
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case 2:
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puts_filtered ("Round up\n");
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break;
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case 3:
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puts_filtered ("Round toward zero\n");
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break;
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}
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}
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/* Print out the i387 floating poin state. */
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void
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i387_float_info (void)
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{
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unsigned int fctrl;
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unsigned int fstat;
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unsigned int ftag;
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unsigned int fiseg;
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unsigned int fioff;
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unsigned int foseg;
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unsigned int fooff;
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unsigned int fop;
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int fpreg;
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int top;
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fctrl = read_register (FCTRL_REGNUM);
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fstat = read_register (FSTAT_REGNUM);
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ftag = read_register (FTAG_REGNUM);
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fiseg = read_register (FCS_REGNUM);
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fioff = read_register (FCOFF_REGNUM);
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foseg = read_register (FDS_REGNUM);
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fooff = read_register (FDOFF_REGNUM);
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fop = read_register (FOP_REGNUM);
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top = ((fstat >> 11) & 7);
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for (fpreg = 7; fpreg >= 0; fpreg--)
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{
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unsigned char raw[FPU_REG_RAW_SIZE];
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int tag = (ftag >> (fpreg * 2)) & 3;
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int i;
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printf_filtered ("%sR%d: ", fpreg == top ? "=>" : " ", fpreg);
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switch (tag)
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{
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case 0:
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puts_filtered ("Valid ");
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break;
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case 1:
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puts_filtered ("Zero ");
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break;
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case 2:
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puts_filtered ("Special ");
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break;
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case 3:
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puts_filtered ("Empty ");
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break;
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}
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read_register_gen ((fpreg + 8 - top) % 8 + FP0_REGNUM, raw);
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puts_filtered ("0x");
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for (i = 9; i >= 0; i--)
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printf_filtered ("%02x", raw[i]);
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if (tag != 3)
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print_i387_ext (raw);
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puts_filtered ("\n");
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}
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puts_filtered ("\n");
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print_i387_status_word (fstat);
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print_i387_control_word (fctrl);
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printf_filtered ("Tag Word: %s\n",
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local_hex_string_custom (ftag, "04"));
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printf_filtered ("Instruction Pointer: %s:",
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local_hex_string_custom (fiseg, "02"));
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printf_filtered ("%s\n", local_hex_string_custom (fioff, "08"));
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printf_filtered ("Operand Pointer: %s:",
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local_hex_string_custom (foseg, "02"));
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printf_filtered ("%s\n", local_hex_string_custom (fooff, "08"));
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printf_filtered ("Opcode: %s\n",
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local_hex_string_custom (fop ? (fop | 0xd800) : 0, "04"));
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}
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