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-rw-r--r--gnu/usr.bin/binutils/libiberty/floatformat.c385
1 files changed, 385 insertions, 0 deletions
diff --git a/gnu/usr.bin/binutils/libiberty/floatformat.c b/gnu/usr.bin/binutils/libiberty/floatformat.c
new file mode 100644
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+++ b/gnu/usr.bin/binutils/libiberty/floatformat.c
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+/* IEEE floating point support routines, for GDB, the GNU Debugger.
+ Copyright (C) 1991, 1994 Free Software Foundation, Inc.
+
+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 "floatformat.h"
+#include <math.h> /* ldexp */
+#ifdef __STDC__
+#include <stddef.h>
+extern void *memcpy (void *s1, const void *s2, size_t n);
+extern void *memset (void *s, int c, size_t n);
+#else
+extern char *memcpy ();
+extern char *memset ();
+#endif
+
+/* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not
+ going to bother with trying to muck around with whether it is defined in
+ a system header, what we do if not, etc. */
+#define FLOATFORMAT_CHAR_BIT 8
+
+/* floatformats for IEEE single and double, big and little endian. */
+const struct floatformat floatformat_ieee_single_big =
+{
+ floatformat_big, 32, 0, 1, 8, 127, 255, 9, 23, floatformat_intbit_no
+};
+const struct floatformat floatformat_ieee_single_little =
+{
+ floatformat_little, 32, 0, 1, 8, 127, 255, 9, 23, floatformat_intbit_no
+};
+const struct floatformat floatformat_ieee_double_big =
+{
+ floatformat_big, 64, 0, 1, 11, 1023, 2047, 12, 52, floatformat_intbit_no
+};
+const struct floatformat floatformat_ieee_double_little =
+{
+ floatformat_little, 64, 0, 1, 11, 1023, 2047, 12, 52, floatformat_intbit_no
+};
+
+const struct floatformat floatformat_i387_ext =
+{
+ floatformat_little, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
+ floatformat_intbit_yes
+};
+const struct floatformat floatformat_m68881_ext =
+{
+ /* Note that the bits from 16 to 31 are unused. */
+ floatformat_big, 96, 0, 1, 15, 0x3fff, 0x7fff, 32, 64, floatformat_intbit_yes
+};
+const struct floatformat floatformat_i960_ext =
+{
+ /* Note that the bits from 0 to 15 are unused. */
+ floatformat_little, 96, 16, 17, 15, 0x3fff, 0x7fff, 32, 64,
+ floatformat_intbit_yes
+};
+const struct floatformat floatformat_m88110_ext =
+{
+#ifdef HARRIS_FLOAT_FORMAT
+ /* Harris uses raw format 128 bytes long, but the number is just an ieee
+ double, and the last 64 bits are wasted. */
+ floatformat_big,128, 0, 1, 11, 0x3ff, 0x7ff, 12, 52,
+ floatformat_intbit_no
+#else
+ floatformat_big, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
+ floatformat_intbit_yes
+#endif /* HARRIS_FLOAT_FORMAT */
+};
+const struct floatformat floatformat_arm_ext =
+{
+ /* Bits 1 to 16 are unused. */
+ floatformat_big, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64,
+ floatformat_intbit_yes
+};
+
+static unsigned long get_field PARAMS ((unsigned char *,
+ enum floatformat_byteorders,
+ unsigned int,
+ unsigned int,
+ unsigned int));
+
+/* Extract a field which starts at START and is LEN bytes long. DATA and
+ TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
+static unsigned long
+get_field (data, order, total_len, start, len)
+ unsigned char *data;
+ enum floatformat_byteorders order;
+ unsigned int total_len;
+ unsigned int start;
+ unsigned int len;
+{
+ unsigned long result;
+ unsigned int cur_byte;
+ int cur_bitshift;
+
+ /* Start at the least significant part of the field. */
+ cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little)
+ cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) - cur_byte - 1;
+ cur_bitshift =
+ ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
+ result = *(data + cur_byte) >> (-cur_bitshift);
+ cur_bitshift += FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little)
+ ++cur_byte;
+ else
+ --cur_byte;
+
+ /* Move towards the most significant part of the field. */
+ while (cur_bitshift < len)
+ {
+ if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT)
+ /* This is the last byte; zero out the bits which are not part of
+ this field. */
+ result |=
+ (*(data + cur_byte) & ((1 << (len - cur_bitshift)) - 1))
+ << cur_bitshift;
+ else
+ result |= *(data + cur_byte) << cur_bitshift;
+ cur_bitshift += FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little)
+ ++cur_byte;
+ else
+ --cur_byte;
+ }
+ return result;
+}
+
+/* Convert from FMT to a double.
+ FROM is the address of the extended float.
+ Store the double in *TO. */
+
+void
+floatformat_to_double (fmt, from, to)
+ const struct floatformat *fmt;
+ char *from;
+ double *to;
+{
+ unsigned char *ufrom = (unsigned char *)from;
+ double dto;
+ long exponent;
+ unsigned long mant;
+ unsigned int mant_bits, mant_off;
+ int mant_bits_left;
+
+ exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize,
+ fmt->exp_start, fmt->exp_len);
+ /* Note that if exponent indicates a NaN, we can't really do anything useful
+ (not knowing if the host has NaN's, or how to build one). So it will
+ end up as an infinity or something close; that is OK. */
+
+ mant_bits_left = fmt->man_len;
+ mant_off = fmt->man_start;
+ dto = 0.0;
+ exponent -= fmt->exp_bias;
+
+ /* Build the result algebraically. Might go infinite, underflow, etc;
+ who cares. */
+ while (mant_bits_left > 0)
+ {
+ int exp_bits;
+ exp_bits = mant_bits_left < 32 ? mant_bits_left : 32;
+ if (mant_bits_left == fmt->man_len
+ && exp_bits == 32
+ && fmt->intbit == floatformat_intbit_no)
+ {
+ /* If there is no integer bit, we need to get only 31 bits
+ so we have room for an integer bit that we create. */
+ mant_bits = 31;
+ }
+ else
+ mant_bits = exp_bits;
+
+ mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
+ mant_off, mant_bits);
+ if (mant_bits_left == fmt->man_len)
+ mant |= 0x80000000;
+ dto += ldexp ((double)mant, exponent - (exp_bits - 1));
+ exponent -= exp_bits;
+ mant_off += mant_bits;
+ mant_bits_left -= mant_bits;
+ }
+
+ /* Negate it if negative. */
+ if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
+ dto = -dto;
+ memcpy (to, &dto, sizeof (dto));
+}
+
+static void put_field PARAMS ((unsigned char *, enum floatformat_byteorders,
+ unsigned int,
+ unsigned int,
+ unsigned int,
+ unsigned long));
+
+/* Set a field which starts at START and is LEN bytes long. DATA and
+ TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
+static void
+put_field (data, order, total_len, start, len, stuff_to_put)
+ unsigned char *data;
+ enum floatformat_byteorders order;
+ unsigned int total_len;
+ unsigned int start;
+ unsigned int len;
+ unsigned long stuff_to_put;
+{
+ unsigned int cur_byte;
+ int cur_bitshift;
+
+ /* Start at the least significant part of the field. */
+ cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little)
+ cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) - cur_byte - 1;
+ cur_bitshift =
+ ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
+ *(data + cur_byte) &=
+ ~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1) << (-cur_bitshift));
+ *(data + cur_byte) |=
+ (stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift);
+ cur_bitshift += FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little)
+ ++cur_byte;
+ else
+ --cur_byte;
+
+ /* Move towards the most significant part of the field. */
+ while (cur_bitshift < len)
+ {
+ if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT)
+ {
+ /* This is the last byte. */
+ *(data + cur_byte) &=
+ ~((1 << (len - cur_bitshift)) - 1);
+ *(data + cur_byte) |= (stuff_to_put >> cur_bitshift);
+ }
+ else
+ *(data + cur_byte) = ((stuff_to_put >> cur_bitshift)
+ & ((1 << FLOATFORMAT_CHAR_BIT) - 1));
+ cur_bitshift += FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little)
+ ++cur_byte;
+ else
+ --cur_byte;
+ }
+}
+
+/* The converse: convert the double *FROM to an extended float
+ and store where TO points. Neither FROM nor TO have any alignment
+ restrictions. */
+
+void
+floatformat_from_double (fmt, from, to)
+ CONST struct floatformat *fmt;
+ double *from;
+ char *to;
+{
+ double dfrom;
+ int exponent;
+ double mant;
+ unsigned int mant_bits, mant_off;
+ int mant_bits_left;
+ unsigned char *uto = (unsigned char *)to;
+
+ memcpy (&dfrom, from, sizeof (dfrom));
+ memset (uto, 0, fmt->totalsize / FLOATFORMAT_CHAR_BIT);
+ if (dfrom == 0)
+ return; /* Result is zero */
+ if (dfrom != dfrom)
+ {
+ /* From is NaN */
+ put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
+ fmt->exp_len, fmt->exp_nan);
+ /* Be sure it's not infinity, but NaN value is irrel */
+ put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start,
+ 32, 1);
+ return;
+ }
+
+ /* If negative, set the sign bit. */
+ if (dfrom < 0)
+ {
+ put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1);
+ dfrom = -dfrom;
+ }
+
+ /* How to tell an infinity from an ordinary number? FIXME-someday */
+
+ mant = frexp (dfrom, &exponent);
+ put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, fmt->exp_len,
+ exponent + fmt->exp_bias - 1);
+
+ mant_bits_left = fmt->man_len;
+ mant_off = fmt->man_start;
+ while (mant_bits_left > 0)
+ {
+ unsigned long mant_long;
+ mant_bits = mant_bits_left < 32 ? mant_bits_left : 32;
+
+ mant *= 4294967296.0;
+ mant_long = (unsigned long)mant;
+ mant -= mant_long;
+
+ /* If the integer bit is implicit, then we need to discard it.
+ If we are discarding a zero, we should be (but are not) creating
+ a denormalized number which means adjusting the exponent
+ (I think). */
+ if (mant_bits_left == fmt->man_len
+ && fmt->intbit == floatformat_intbit_no)
+ {
+ mant_long &= 0x7fffffff;
+ mant_bits -= 1;
+ }
+ else if (mant_bits < 32)
+ {
+ /* The bits we want are in the most significant MANT_BITS bits of
+ mant_long. Move them to the least significant. */
+ mant_long >>= 32 - mant_bits;
+ }
+
+ put_field (uto, fmt->byteorder, fmt->totalsize,
+ mant_off, mant_bits, mant_long);
+ mant_off += mant_bits;
+ mant_bits_left -= mant_bits;
+ }
+}
+
+
+#ifdef IEEE_DEBUG
+
+/* This is to be run on a host which uses IEEE floating point. */
+
+void
+ieee_test (n)
+ double n;
+{
+ double result;
+ char exten[16];
+
+ floatformat_to_double (&floatformat_ieee_double_big, &n, &result);
+ if (n != result)
+ printf ("Differ(to): %.20g -> %.20g\n", n, result);
+ floatformat_from_double (&floatformat_ieee_double_big, &n, &result);
+ if (n != result)
+ printf ("Differ(from): %.20g -> %.20g\n", n, result);
+
+ floatformat_from_double (&floatformat_m68881_ext, &n, exten);
+ floatformat_to_double (&floatformat_m68881_ext, exten, &result);
+ if (n != result)
+ printf ("Differ(to+from): %.20g -> %.20g\n", n, result);
+
+#if IEEE_DEBUG > 1
+ /* This is to be run on a host which uses 68881 format. */
+ {
+ long double ex = *(long double *)exten;
+ if (ex != n)
+ printf ("Differ(from vs. extended): %.20g\n", n);
+ }
+#endif
+}
+
+int
+main ()
+{
+ ieee_test (0.5);
+ ieee_test (256.0);
+ ieee_test (0.12345);
+ ieee_test (234235.78907234);
+ ieee_test (-512.0);
+ ieee_test (-0.004321);
+ return 0;
+}
+#endif
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